Finding good pond care advice is not always easy. On-line you will find wildly conflicting advice and advice that runs from incredibly good to unbelievably stupid. Even pond books will conflict with each other on occasions
Our advice is firstly geared to the Hampton Roads area. We assume if you are shopping with us that you live near us. If you live in Buffalo New York, some of our advice will not apply, same if you live in Tucson Arizona. (One of the many advantages of shopping local)
We know the local conditions and requirements and have a combined pond care experience of over 60 years. We’ve made many many mistakes in that time so that we can guide you and help you to not make them. We test every new product we carry before we sell it and we won’t carry any product that we won’t use outside, allowing us to knowledgeably answer your questions.
There is a good deal of overlap in the topics below, but we hope that you will find they are all worth reading and useful.
-Dawn Penman and Jeff Halvorson
Mechanical filtration is the primary type of filtration for swimming pools, but should be used only as supplementary filtration on a pond. Mechanical filtration physically stops debris so it can be removed. It does nothing to remove liquid or semi-liquid wastes. In a pond it is primarily used in skimmers or prefilters to keep debris out of the pumps. On its own it is insufficient to keep a pond healthy.
Chemical filtration is commonly used in aquariums but typically used in ponds only for special circumstances. Chemical filtration consists of running the pond water through a bed of media which removes undesirable chemicals and/or toxins by bonding them with the media. The most common types of chemical filtration are activated charcoal to remove chemicals, medicines or tannic acid discoloration of the water and zeolite (ammorocks) to remove ammonia. Chemical media needs frequent replacement or regeneration, as it “fills up”.
Ultraviolet filtration is highly recommended for both planktonic (microscopic floating) algae and disease prevention. As the water passes in front of a UV light, the light kills whatever is in the water. There are several key things to keep in mind with a UV installation. The first is that you should have at least 1 watt of light per 100 gallons. Next is flow rate. If the water passes the light too fast, the light does not have enough time to do its job. Some lights are marketed as clarifiers, some as sterilizers. A clarifier will kill algae but not disease organisms, where a sterilizer will do both. The only difference in reality is flow rate. Slow down the flow through a clarifier and it becomes a sterilizer, speed up the flow through a sterilizer and it becomes a clarifier.
Vegetative filtration is simply running the water through plants, either floating or planted. All plants will help pull the nitrates and phosphates from pond water. Nitrates and phosphates are fertilizers and can promote excess algae growth. The most efficient are floating plants, then bare root plants, then plants in mesh pots and least efficient are plants in hard pots. Bare root plants are most efficient when water is forced through the gravel they are in.
Biological filtration is the most important type of pond filtration. Water is run through a bed of media that nitrifying bacteria grow on. The bacteria break down and digest the organic wastes in the water, both liquid and semi-solid. The filter media can be mats, bioballs, lava rock or anything similar. The bacteria grow on all the available surfaces. With constant water flow, aerobic bacteria grow. Without constant water flow through the media, anaerobic bacteria replace the aerobic. Anaerobic are only about 10% as efficient as aerobic bacteria and generate hydrogen sulfites, which stink. A biological filter should ideally be cleaned no more than once a year, as cleaning will kill your bacteria and it takes three to six weeks to fully re-establish the bacteria colony. The bacteria colony, or culture, also has a tendency to weaken over time. Adding fresh bacteria with enzymes will constantly refortify the microbe culture.
Submerged filters- these typically come with small pond kits. We do not recommend them as they require a great deal of maintenance and aren’t particularly efficient. Typically need to be cleaned up to several times a week.
Pressurized filter- similar to a bead filter, but typically will have filter pads inside. Comes apart to clean the inside. Good for smaller ponds where a waterfall or bog is not practical. Usually need monthly maintenance
Bead filters- very efficient but also expensive. These look very much like swimming pool filters, with a bead type of media instead of sand. They are best for formal ponds or strict koi ponds (as opposed to water gardens). As they do not remove nitrates, partial water changes are recommended for ponds with beads filters as their primary filtration. Hard to hide unless a pump room or well is built and needs to be backwashed at least monthly. Also, not very efficient at controlling particulates.
Waterfall filters- our preferred type of filter. If large enough (that is, if it holds enough media) it can provide all of your filtration. With rocks and plants it can be hidden and so provides a very natural look. Should need to be cleaned only once a year.
Bog filter- the best. If you have room, it combines the best of biological and vegetative filtration. A bog equal to 20% of the surface of the pond will provide sufficient filtration for even a crowded pond. A bog filter should be shallow – it does not need to be more than 12” deep. It should have a grid network in the bottom so that water comes up evenly throughout the gravel in the bog, so as to prevent anaerobic bacterial growth.
Gravity filters- sort of a cross between a waterfall filter and a pressurized filter. Potentially very efficient, but hard to hide. Excellent for quarantine or holding tanks or ponds where a waterfall is not practical. Much less maintenance than a pressurized filter.
Aeration is not true filtration but an adjunct to your filtration. In a typical pond with a skimmer and waterfall, only the top 12” to 18” of water gets moved and filtered. The water in the bottom of the pond tends to stagnate and get de-oxygenated. Adding airstones to the pond bottom causes water from the bottom to constantly move up into the filter stream where it can get oxygen and be filtered, also bringing small particulate matter up with the bubbles to get picked up and removed.
Additionally, aeration may become critical in hot weather. The warmer water is the less oxygen it holds, while the fish’s metabolism speeds up and more oxygen is needed. Airstones help insure that the water is holding the maximum possible amount of oxygen. Anytime fish are seen at the surface gulping for air you should start worrying. Oxygen deprivation typically kills the biggest koi first.
Aeration also helps in the winter in keeping part of the surface ice free for gas exchange. Some books and on-line sources will tell you not to mix surface air/water with the deeper water during the winter, but that simply is not a concern in our area.
There are three main types of problem algae found in ornamental ponds. First and most common is green water algae, or planktonic algae. This appears as a green tint to the water, often so thick that the water looks like pea soup with visibility of no more than an inch or two. The other types are string algae, which looks like clumps of fur growing on everything in the pond and blanket algae, which forms a free floating mat in the water. A thin coating of algae on all underwater surfaces is normal and good for the pond’s health.
Green water algae is the most common algae problem, but is not harmful to the fish. It is actually the best environment for newly hatched fry to grow in, but a pond that is too green to see fish in is no pleasure to own.
There are several approaches to eliminating green water. Short term, chemical algaecides are effective, but they break down as they kill the algae, leaving nothing to prevent the algae from coming back a week later.
Additionally, killing large quantities of green water algae at once will cause oxygen deprivation problems as all of the dead algae starts breaking down at once and stripping oxygen from the water. For this reason using a chemical algaecide in hot weather is particularly dangerous and a frequent cause of fish kills. A better approach is an ultraviolet light in the pond’s filtration system. As the algae passes in front of the light, the ultraviolet radiation kills it. The biggest problems with this method are the use of either too small a light for the pond volume or too large a pump for the size of light. In general, at least 1 watt of light is needed per 100 gallons of pond volume, with the pump then sized to achieve the recommended flow rate for that light. The third method of algae control is the use of a barley product. Many years ago, Scottish farmers noticed that when there was rotting barley in their farm ponds, algae did not grow. Small barley bales came to be used in ornamental ponds to control algae, but they are only effective when rotting, and take several weeks to rot enough to start working. Barley pellets and liquid extract were developed to give faster results. Barley products typically last for four to six weeks per application. The last method of algae control is to use plants to out compete the algae for nutrients and so starve the algae to death. Higher plants are more efficient at pulling nutrients from the water and leave the algae with no food to grow on. Water hyacinths are the single best plant for this. Most natural ponds will have a spring algae bloom as algae begins to grow earlier in the season than other plants. Once the other plants really start growing, the algae dies back.
We generally use a multipart approach to algae control – algaecide to kill what is there and plants with barley or ultraviolet light to keep it from coming back.
String and blanket algae will not be affected by an ultraviolet light as they won’t pass in front of the light to be irradiated. Powdered algaecides with oxygen releasing chemicals work very well to kill the algae, with plants and supplemental doses of a tablet algaecide to prevent its return. It is common to have string algae present in waterfalls and bogs, as this is where the highest concentrations of nutrients are. The bacteria in the falls or bog have just released the nutrients and the plants haven’t had a chance to remove them yet. Best solution? Plant plants to hide the algae in these locations.
Koi are cold blooded animals and so their metabolism is very dependent on water temperature. Ideal water temperature for koi is 62 degrees through 84 degrees. At 70, food will pass through a koi’s system in about 2 hours, at 60 it takes about a day. Below 45 degrees, digestion stops and over 90 degrees food passes through so fast that the koi get no benefit from it and it only fouls your water.
As water temperatures go up in the spring you can feed your koi more often. Our recommendation on feeding is to start feeding once a week when the water temperature is between 45 and 55 degrees, twice a week for temperatures between 55 and 60 degrees, three times a week for water temperatures of 60 to 65. From 65 to 70 degree temperatures we recommend daily feeding, up to twice daily for 70 to 75 degree temperatures and up to four times daily for temperatures of 75 to 85 degrees. At 85 to 90 degree temperatures, drop back to no more than one feeding daily and when the water temperature goes above 90, stop feeding altogether. Floating thermometers are available for ponds, as are wireless digital ones that can give you a pond temperature readout inside your house.
When going on vacation, if you are going to be gone for less than a month, the best thing to do about feeding your fish is nothing. The worst thing to do is get someone unfamiliar with your pond to feed your fish. Overfeeding will cloud your water, overload your filter and potentially harm your fish. Your fish will find algae, plants and insects and insect larvae to eat while you are gone, and can easily go for weeks without eating fish food. Vacation feeding blocks are available, but even the manufacturers of these admit they are just to make the fish owner feel good. Auto feeders are available for people who will be gone more frequently or otherwise cannot feed their fish on a regular schedule.
Because you should not feed when temperatures go below 45 degrees, for this area we recommend stopping feeding at Thanksgiving and restarting around St. Patrick’s Day. Temperatures may be high enough to feed a week or so either side of these dates, but it will do no harm to start and stop on these dates anyway, and they are easy to remember. To prepare the fish for not eating all winter, you should feed a high carbohydrate or wheat germ food for at least six weeks in the fall to build up their fat reserves. You will want to feed them this again for about two weeks in the spring to replenish their fat layer before switching to a high protein summer diet to build muscle mass and help the koi grow. When switching foods, the transition is helped by mixing the two foods together for about a week or so. Keep in mind that your fish need at least two weeks for their metabolism to speed back up to the point where they can safely eat. Two or three days of warm weather in the winter does NOT mean that you can feed your fish, even if they beg for food and “well, the book says I can feed them if the temperature is over 55”. Remember, your kids want to eat the whole bag of candy at Halloween, but if you let them, they will get sick.
There are two basic food additives to brighten fish colors. Most color enhancing foods contain a combination of spirulina algae and ground up shrimp, lobster or other crustacean shells, which tremendously brighten the yellows and oranges on your koi. Koi clay as a food additive contains micronutrients that deepen and brighten darker colors like the reds, browns, blues and blacks. Koi clay also helps the digestibility of food. Some of the better foods add microbes to help the digestibility of their food. The better the digestibility, the less waste for your filter to have to clean up.
In general, the higher the protein content of a food, the better it helps build muscle and helps with growth. The higher the corn or filler content, the more it just turns a fish fat.
Foods typically are available as pellets, sticks or flakes and floating or sinking. Our recommendation is for pellet or stick foods, as flake foods for koi or pond goldfish are harder to eat in the volume they should have. Koi and goldfish are both natural bottom feeders and so a sinking food is a more natural diet, but a floating food does them no harm, is just as healthy for them and much more fun for you as the owner to watch them eat.
Without addressing individual diseases there are many things you can do to help keep your fish healthy. The first thing we are going to recommend to you is to use an adequate style ultraviolet light in your system year-round. You don’t need it in the winter for algae control, but it is still very useful for disease control, especially in this area where we may have two or three seventy-degree days in a row in the middle of winter. It needs to be sized to your pump at the lower end of the light’s recommended flow rate, so as to act as a sterilizer and not just a clarifier. This is going to help disease transmission by killing off most disease organisms in their free-swimming state.
Next, we want you to keep a trace amount of salt in your water. Using aquarium or pond salt at low levels helps your fish three ways. It helps their gills function better and easier by raising the osmotic pressure in the water. It stimulates the fish to produce a heavier slime coat, which helps to protect against cuts and scrapes. Thirdly, it kills off the free-swimming state of ich, or white spot disease, costia and chilonadela among others. At a level of .014 % it will not hurt your plants or any other fish. This equates to approximately one and a quarter cups of salt per hundred gallons.
Even if you never introduce new fish or plants to your pond, birds are constantly using your pond as a giant birdbath, along with every other pond in the wild, and they bring you disease organisms on their feet and in their feces. To help with this we recommend doing a twice yearly prophylactic treatment, early spring and late fall, with Broad Spectrum Disease Treatment (a malachite green / formalin combination medicine) to eliminate any parasites that have found their way in.
What type of food, how much and when is also an important aspect of your koi health. Early spring and fall you want to feed a high carb food to help with the fish’s fat reserves. Summer is for feeding a high protein food to help them grow. No food in the winter. Keep in mind that your fish need at least two weeks for their metabolism to speed back up to the point where they can safely eat. Two or three days of warm weather in the winter does NOT mean that you can feed your fish, even if they beg for food and “well, the book says I can feed them if the temperature is over 55”. Remember, your kids want to eat the whole bag of candy at Halloween, but if you let them, they will get sick. The lower the temperature, the less food you feed. As with all pets, the better quality food, the healthier the fish.
Spring is the most dangerous time for your fish. As the water warms, it takes your fish several weeks to adjust to the higher temperatures and their immune system is at its lowest effectiveness. Bacteria and parasites on the other hand need only a day of warm weather to get themselves up to speed. They are the biggest cause of spring fish deaths. All you can do is watch carefully this time of year, keep your salt up, do your spring parasite treatment and change your uv bulb early, before it gets too warm, so it is working at it’s peak efficiency just when you need it the most.
MOST IMPORTANTLY, be careful where you get your fish and plants! New fish and plants are the most common way disease gets into your pond. Plants from the wild should be soaked in an anti-parasite solution before being introduced into your pond. Fish from private individuals or questionable sources should be quarantined for a minimum of 21 days before being introduced into your pond. We hear a dozen or more horror stories every season from people who added fish from a friend’s pond or a big box pet store and are now losing fish left and right to some ailment. If you aren’t sure, ask the place you get your fish or plants from about their quarantine protocol. We get our fish from one breeder only, and direct from the breeder, not through a distributor. We do not take fish from a private individual except in the most rare situation, and if we do, we quarantine them for at least 30 days. The breeder we use quarantines their fish for two to three weeks before they ship them and we keep them in tanks with uv lights and high salt (.025-.030) while they are here.
You need catfish to clean your pond. Catfish really do little to clean a pond, koi and goldfish are actually better scavengers than most catfish. The typical catfish sold for ponds grow very big very fast and eat all of your little fish.
Snails help you control algae. An adult Trapdoor snail of the kind typically sold for ponds can keep an area about two square feet clean of algae. That means you need lots and lots of them to eat all of your algae. Most of what they eat is the thin film of algae that grows on your rocks and liner, which is actually very beneficial and you would be better off to keep it. Also, big koi (say, 12” and larger) find your snails to be a very tasty though expensive snack.
If you let your water sit overnight you don’t need to dechlorinate. This was true when cities actually used chlorine in the water. They don’t anymore. Now they all use chloramines, which take up to six weeks to break down on their own.
If you just add a little water, you don’t need to dechlorinate. We hear this one a lot and see it on the internet. “I’ve been adding water for years without dechlorinating and my fish are just fine”. Well, they aren’t. Adding just 5% or even 10% chlorinated water to your pond may not immediately kill your fish, but it burns their gills a little bit each time and it takes them months and months to heal from it. It is equivalent of making them smoke a couple of packs of cigarettes each day. It might not kill them immediately, but it sure affects their health and lifespan.
You need to move all of your plants to the bottom deepest part of the pond for the winter. Maybe if you live in Buffalo New York, but not here. Take out your floating plants at the first frost and toss them, then leave the rest of your plants right where they are for the winter.
You need to heat the pond in the winter or take your fish inside. Koi and goldfish both do not mind cold temperatures at all. You can even freeze them in a solid block of ice and they will be fine if allowed to thaw out naturally. The danger is if the entire surface freezes but the deeper parts of the pond don’t. Even dormant the fish are breathing very slowly and other organic processes are taking place. CO² builds up in the water and can’t release into the air and becomes toxic. Your pond needs a small ice free area, but doesn’t need the whole pond heated.
You need to clean your filter every week or every month. Cleaning your filter too often is counter productive. Completely cleaning a filter will kill all of the beneficial bacteria growing in it and it will take up to a month to fully re-establish itself and cycle, leaving your fish vulnerable to ammonia poisoning during that time and to particulate build-up.
You need to change 10%/15%/20% of your pond water every month. This one does have some small basis, but not much. A pond with no plants will build up nitrates and phosphates to annoying but not dangerous levels over time. Plants in a pond will take care of this for you. Water hardness will also build up for you over time, but it takes a long time in our area for it to become a problem. We would recommend a 50% water change once a year as sufficient to deal with these issues. If you have no plants and high phosphate you might want to do a change every six months, but not monthly.
You can’t mix koi and goldfish in a pond. Common as this belief is, it’s just plain silly. They are both just different species of fancy carp. They are fine together.
You can’t keep plants with koi. Anyone who has been here and looked at our display pond in the summer knows that this one is wrong. The trouble arises when you don’t have enough plants. One or two water lilies with twenty koi and the plants have no chance. You have to have enough plants that they can grow faster than the koi eat them. Lots of plants. I mean lots and lots of plants.
You need to clean the green slime off the sides and bottom of your pond. This one isn’t so much a misconception as a desire for some people. The answer is Don’t. The green slime growing on everything in your pond is highly beneficial to your ponds health. Called your biofilm or pond patina it is a collection of algae, bryozoans, bacteria and even microscopic crustaceans and is critical to the long term health of your pond.
If I have a pond, I’ll have a mosquito problem. Actually, with a pond you usually have fewer mosquitoes. Koi and goldfish will eat any mosquito larvae that show up in your pond, and ponds attract dragonflies. A dragonfly (known in much of the world as a mosquito hawk) will eat near it’s weight in mosquitoes daily. Your pond will also attract frogs and toads who will eat mosquitoes as fast as they can.
I can save on my electric bill with a timer to turn my pump off at night. Unfortunately, pond filtration depends on bacteria that needs constant water flow to stay alive. Four hours of no water flow and half of your bacteria has died, ten hours and 90% of it has died and it can take weeks to recover.
I can put gravel in the bottom of my pond for appearance. Gravel in the bottom of a pond traps fine debris which rots there creating issues with your water quality. Rocks on the bottom should be at least the size of eggs so you can get water flow between them and should be smooth rather than sharp so they don’t puncture your liner. You are perfectly fine putting nothing in the bottom.
Neighborhood cats will eat my fish. We have four cats at the shop. I have two at home. None have ever bothered the ponds. As a general rule, cats don’t like getting wet. They will drink out of the ponds and watch the fish, but that’s all. When someone comes in and says “My neighbor’s cat ate my fish” our reply is “No it didn’t. It was a possum or a racoon or a heron, but it was not your neighbor’s cat.”
I can’t have a pond, I have too many trees / I have too much sun. You can have a pond almost anywhere. If it’s in lots of shade, put a net up in the fall to keep most of the leaves out. If it’s in full sun, an ultraviolet light becomes even more important. We have pond plants for both full sun and for full shade, and many that will do both. Your fish won’t care.
Having a pond will greatly increase my water / electric bill. Fortunately for us, water in Hampton Roads is relatively inexpensive. You will only completely fill your pond once, then top it off as water evaporates. Our display pond is 3300 gallons and it costs a little over $10 for the water to fill it, and probably $30 to $40 over the course of the whole year to keep it filled. Our display pond costs about $60 in electric per month to run, but we have a lot going on with it. Our smaller goldfish pond runs about $20 a month to operate.
As long as my UV bulb comes on and glows blue, it’s working. Sorry, not true. UV bulbs have a useful life of about 9,000 to 10,000 hours. Note we said useful. UV bulbs are a type of fluorescent bulb and all fluorescent bulbs get dimmer as they age. After about 9,000 to 10,000 hours your bulb has dimmed enough that it is no longer strong enough to kill what it needs to. It may come on and glow blue for another two years or more, but after that first 10,000 hours, it’s just a very expensive nightlight.
There are at least six different types of cloudiness of your pond water, and they each have a different cause and solution.
Let’s address the last one of these first. #6. This cloudiness is typical of a brand new pond and just means that no matter how well you think you washed those rocks, you didn’t get all of the mud and silt off of them. What to do? Nothing. Wait anywhere from a few days to a few weeks and the filter will trap all of this. Don’t waste your time / money trying to speed it up with chemicals, this is inorganic sediment and those “clear the pond fast” chemicals are for organics. Sit, have a drink and wait. Or do a bunch of water changes.
Next, #1. Green Water. Green water is microscopic algae floating in your water, making it look like the water has been dyed green, or in bad cases, like pea soup. The absolute best fix is to install an Ultraviolet light in your system. The light must be correctly sized to both your pond and your pump. If you have a UV light and your water is still green, either your light is too small for the pond, too small for the pump, your bulb is too old (the bulbs are only effective for one year – they will come on and glow for much longer, but after about twelve months they are no longer strong enough to kill the algae) or you got a cheap Chinese made bulb, most of which are very ineffective. Lacking a UV light, the next best solution is to use either barley liquid or pellets combined with lots of plants. The barley products inhibit algae growth and the plants outcompete the algae for nutrients and starve it to death. Third and fourth solutions would be either barley products or plants by themselves. Last, and highly discouraged solution is a liquid algaecide. Liquid algaecides kill quickly but do not remain in the water. Killing too much algae too quickly can result in a lack of oxygen in the water that can kill your fish. Additionally, new algae spores land from the air and start growing the next day, and algae can double in volume every six hours.
#2. Brown Particulate Cloudiness. Particulate cloudiness is caused by insufficient, inefficient, or overloaded filtration systems. Keep in mind that most manufacturers seriously over-rate their systems. Assuming an adequate system, temporary overloads can be caused by overfeeding (you must cut back on feeding at both very high and very low temperatures), cleaning your filter at the wrong time (early spring and late fall ONLY) as cleaning sets your filter back by several weeks, not adding beneficial bacteria to the system regularly or inefficient water flow not taking debris to the filter. This last can usually be remedied by adding airstones / aeration and / or relocating the pump.
#3. Brown Iced Tea like Tint. Iced tea water is the result of tannic acid discoloring the water. It is caused by leaves and similar debris in the water breaking down. Any leaves, sticks and branches should be kept out of the pond or removed as soon as possible. All woody plant leaves are bad, but green leaves are worse than dried leaves, pine needles and oak leaves are particularly bad and acorns are the worst. This condition will go away on its own, but it may take months to do so. Activated charcoal in the filter stream will remove it, or a water change.
#4. White Cloudiness. White cloudiness is usually caused by a bacterial bloom in the water and as such seldom lasts long and is frequently self-correcting. Adding a mild anti-bacterial such as Melafix will help.
#5. Grey Cloudiness. Grey cloudiness is generally from an elevated phosphate level in the water and can be corrected with either a water change or a chemical to lower the phosphate level. Always test the phosphate level first to confirm before treating though. Elevated phosphates can come from overfeeding, overcrowding, inefficient filtering or simply be present in your source water.
Basic water testing can tell you many things about your pond, but many things can not be practically tested for. Typical pond testing will not show the presence of most chemical or organic poisons, nor will it show the presence of disease organisms.
Usually pond water is tested for pH (a measure of the acidity or alkalinity of the water), ammonia level, nitrite level, nitrate level, phosphate level and salt level. Additionally, hardness testing, both general and carbonate, may be informative and for some problems copper or iron testing may be indicated. All of these tests are readily available to the pond hobbyist. More advanced testing or testing for poisons or disease organisms are usually done by a specialty lab.
We use and recommend liquid drop type test kits rather than test strips. Test strips, particularly multitest ones, are very difficult to distinguish fine gradations with and only have about a 12 month shelf life, frequently making them out of date shortly after or even sometimes before you buy them.
What do these tests tell you? Let’s start with pH. pH is a measure of the acidity or alkalinity of your water. The scale ranges from 0 to 14, with 7.0 being neutral. Koi will thrive with the water anywhere between 6.5 and 8.0 and if your water is in that range you need to do nothing to it. Below 6.0 your fish are in immediate danger and a pH increasing chemical should be added or a major water change begun. Above 9.0 your plants will usually start to suffer first, but your koi will eventually also be affected. Many commercial products are available to adjust your pH up or down, with various effectiveness. It is best to use a buffer to help stabilize the pH after you have it in the correct range. A buffer helps keep the pH from fluctuating up or down.
Ammonia and nitrite are both toxic byproducts of the breakdown of organic wastes in the pond. Additionally, ammonia is exuded directly from the fish’s gills. In any new set-up or any time the biological filter is cleaned and restarted the ammonia level will climb for the first 14 days or so until the bacteria in the filter catch up on processing it. After the ammonia spikes, the next week to ten days will see an increase in nitrite until it spikes and starts back down. There are commercial products to help lower both of these until they level out. In a mature pond they should both read zero to negligible.
Nitrate is the final stage of the pond’s biological filtration cycle. High nitrate levels are not usually toxic to your fish unless extreme. Nitrate is a plant fertilizer and sufficient plants will remove the nitrate. High levels of nitrate and phosphate will feed algae blooms and without enough plants, water changes may need to be done to keep these levels under control.
Salt is used to help with the fish health. At levels of 0.10 to 0.14 percent it will not hurt plants and at levels of 0.20 to 0.30 is therapeutic in non planted ponds. Levels of 0.40 to 0.50 are suitable for hospital / quarantine tanks. Liquid drop test kits are no longer available to the hobbyist. Digital salt testers are available but expensive. Salt water aquarium salt level testers don’t read finely enough for the small levels used in ponds. This leaves you with bringing a sample to someone to be tested, but, as salt does not evaporate out and is only lost when you have an overflow, leak or do a water change, it is sufficient to test your salt level two or three times a year.
Chlorine / chloramines testing should not be necessary as chloramines remover should be used any time tap water is added to a pond. For practical purposes you can not overdose on dechlorinator, as even 100 times the recommended dose will not hurt your fish or plants.
In review, we recommend testing your pH at least monthly. Test your ammonia monthly unless you have a new set-up or have cleaned your filter. If either of those is the case, test both ammonia and nitrite daily until they level out at close to zero and chemically adjust as needed. Test your salt, phosphate and nitrate about once every four months.
Koi will live to be over 200 years old in exceptional circumstances, however, average lifespan tends to be around 25 to 35 years.
Maximum length is a little over 3 feet. Koi can reach 18” to 20” inches in 3 to 4 years under the right conditions. They will usually only grow to the size of their pond.
Koi can be fed four or five times a day in midsummer, tapering down to once a week by early winter. They can easily go 10 days or more without being fed anytime of the year. They do not need to be fed at all during the winter.
For healthy koi and a healthy pond, the water should be constantly filtered and aerated. We recommend the complete volume of the pond be run through the filter at least once per hour.
The selling price of koi is determined not just by size, but by origin (Japanese or domestic) and by body shape, color, and pattern.
Koi can withstand a wide range of temperatures, but sudden temperature changes are not good for them. They can easily survive under ice in a frozen pond, but care should be taken not to break the ice in such a way that it transmits the shock to the koi. Koi will go dormant at low temperatures and stay almost motionless at the bottom of the pond.
Some fish will just inexplicably die, but overall, koi are remarkably hardy and healthy fish; much more so than goldfish or tropical fish. Chlorine or chloramines in city water or windblown insecticides are the biggest dangers to koi, along with predators. Smaller koi have a much higher mortality rate than larger ones, and are more susceptible to disease and changes in the environment.
Koi get along well with most other pond fish, especially goldfish, golden orfes and mosquito fish. Large catfish (12” to 18”) will eat small koi (3” to 5”).
Koi must be at least 3 to 4 years old and about 10” or longer to spawn. A single female may lay thousands of eggs at a time. The eggs hatch in about 3 to 7 days and can be removed to a different location so they won’t get eaten. The survival rate is usually much less than 50%. At two inches or so they can usually go back into a large pond.
Koi are the most common pond fish. They are originally bottom feeders bred from an Asiatic carp by Japanese rice farmers. They will for the most part be limited in size by the size of the pond they are in, though there will be some sports who do outgrow their environment. Under ideal conditions they can grow to about three and a half feet long. Most of their growth will be in their first three years. If they are kept exclusively in a small pond when young, they will never reach their potential full size. They will start spawning when about two to three years old. They usually spawn in spring, typically in March, April or May. Koi and goldfish can interbreed, though they do so infrequently.
Goldfish were bred from European carp and do very well in an ornamental pond. They can attain a length of up to two feet in a large enough pond. They are prolific breeders and will spawn their first summer if large enough, and spawn in spring, summer and fall. Though not as colorful as koi, they have much more variety in body shapes. Not all of the very fancy types do well outside, particularly in the winter. Comets, Sarasa comets, Veiltails, Fantails, Calicoes and Shubunkins are all goldfish varieties that make excellent pond inhabitants.
Golden Orfes are a top feeding schooling fish. They are completely unrelated to goldfish and koi. They are native to Europe and exist there in both golden and silver versions. The silver version is seldom available in the U. S. They should be kept in schools of at least 4 to 6 fish and will typically get a foot to a foot and a half in length. The are incredibly hyper and are always flitting about the pond. They particularly enjoy leaping up into waterfalls and leaping after gnats and other insects.
Due to their constant activity and jumping, they should be kept in a pond of at least 1000 gallons; with surface area being more important than volume (a very shallow 800 gallon pond is better than a deep 1200 gallon one.)
Mosquito fish (Gambusia sp.) grow to about two inches for females and one inch for males. They are livebearers and breed prolifically. They are excellent for container gardens or small bodies of water where bigger fish cannot get, as koi and goldfish will also eat mosquito larva. They are fun in a large pond anyway, as they are entertaining to watch as they eat. They will easily winter over in an outside pond in this area.
Channel catfish are typically available in either blue (natural) or gold (albino) versions. Either will do fine in an ornamental pond, provided that it is understood that they are not necessary, as, contrary to common belief they do little or nothing to clean your pond. Koi are better scavengers than catfish. Large catfish can be ornamental, but will usually eat anything that will fit in their mouths, including small fish. Small catfish become large ones in a year or two at most. They do an excellent job of controlling goldfish overpopulation.
European Dace are a large surface fish, very similar to a silver Orfe. These are seldom available in the U. S. American Dace are a much smaller minnow type fish. Dace, killifish and other small minnow type fish will frequently show up in ponds from eggs that come in on plants, notably Water Hyacinths, Water Lettuce, Anacharis and Cabomba. They are harmless and add to your biodiversity, but are seldom available commercially.
Many varieties of snails are available for your pond. Small snails, both pond snails (long pointy shells) and ramshorn snails (flat round shells) will show up in your pond without you doing anything. They arrive as eggs on plants and as eggs or babies on birds’ feet. They will do very little to clean your pond and will eat your plants, but adult koi and goldfish will eat these snails. You will notice them most in skimmers and filters where your fish cannot get at them. A mid sized snail for ponds is the Columbian Ramshorn snail. They typically don’t bother plants and add a little color with their striped shell. Larger snails for a pond are Japanese Trapdoor snails, Mystery Snails and Apple snails. These three varieties all look very similar. Apple snails are the largest and also the most voracious plant eaters. Mystery snails do some plant eating and some algae while Japanese Trapdoor snails are almost exclusively algae eaters. Japanese Trapdoor snails also breed slowly enough not to overpopulate a pond.
Freshwater clams were common years ago to help keep ponds clean, as they filter a tremendous volume of water through their bodies. However, to keep them you need a bed of relatively clean sand on the bottom of the pond. With the advent of modern reliable pumps, clams are now seldom kept in the backyard pond.
Crayfish and freshwater shrimp are frequently introduced to ponds and will help clean your pond, but are also eaten and / or picked on by the larger fish and so don’t really do well in the typical backyard pond.
Tadpoles are a frequent addition to backyard ponds. Those usually available for sale are bullfrog tadpoles, which stay tadpoles for about two years. After becoming frogs, they will grow very rapidly to a large size. On occasion frogs may eat smaller fish like mosquito fish and young goldfish or koi.
Frogs of all types may show up in your pond on their own. Toad tadpoles, which are small (about ½” long) and black frequently show up in ornamental ponds, but only remain tadpoles for about three weeks before becoming toads. Tree frog tadpoles also frequently show up in ponds, taking several months to grow into frogs.
Turtles, such as red-eared sliders or painted turtles, are a fun addition to your pond. They are entertaining to watch, though they will munch on your plants and eat very small fish, making them a better addition to a large pond than a small one. They are also more likely to stick around in a large pond. They need to have someplace to get out of the water to sun themselves to prevent shell rot.
Many tropicals can be placed in your pond during the warm summer months. The most commonly placed in a backyard pond are plecostomus catfish, used as algae eaters. They may grow up to two feet long in an outdoor pond. They must go back inside by late September. Swordtails and mollies are also frequently put outside for the summer.
Native fish can be put in ornamental ponds but it not usually recommended. Wild stocks are frequent carriers of disease, many wild fish are voracious predators and in many states relocating live wild fish is illegal. If native fish are to be introduced to the pond, it is recommended that they come from a hatchery.
Hi-fin sharks are a cold water hardy algae eater in the catfish family that will do well in an outdoor pond. In a large enough pond they can easily reach a foot and a half in length, but even at that size won’t bother other fish, even little ones. As they are not yet bred commercially, but are all wild caught in China and imported they tend to be somewhat pricey, but they are fun to watch. The intensity of their coloration and stripes seems to vary considerably with mood, temperature, time of day or other unknown factor.
Unfortunately there is a long list of predators in Hampton Roads who would be interested in your fish. Fortunately, most can be dealt with without too much trouble.
Predators who will try to get your fish: Kingfishers, Herons and Egrets, including Green Herons, Night Herons, White Egrets, and Great Blue Herons, Barred Owls, Ospreys, Bald Eagles, Cormorants, Possums, Racoons, Otters, Minks and Bears. We can tell you what to do for all of these except the bear. You got bear problems, you are on your own. Many people think neighborhood cats are an issue, but this is extremely rare. Cats will watch the fish and drink out of the ponds but don’t like getting wet. Between Dawn and Jeff and the shop we have seven cats. Not one has ever bothered a fish.
The most common way of dealing with predators is to net your pond. This works well for all of the birds, somewhat for possums and raccoons, but not very well for otters or minks. When netting your pond you have several types of netting available. Bird netting is available at many garden centers and big box stores. It is a thin extruded plastic which tears fairly easily, lasting about a year or two. Bird netting usually has ¾” mesh. We carry the same type netting but as pond netting it has a finer 3/8” mesh. We also have available a heavier duty, longer lasting 5/8” mesh woven netting.
Netting should never, despite pictures on some packaging, be floated on the surface of the pond. As your fish eat they can injure their mouth on floating netting. Simply pulling the netting tight will raise it out of the water, though when leaves get on it they can sag it back into the water. We recommend either making an arched support or buying a premade one to lift the net up. This also keeps the net from interfering with your plants.
Two solutions for herons and egrets are monofilament fishing line, either strung as a fence about 18” off of the ground on the very edge of the pond or strung back and forth over the pond to form a grid of about 15” squares. Herons and egrets tend to land outside a pond and walk in. Even though they have very long legs, they can’t bend them well enough to step over something tall. However, if they are given even a tiny area inside the barrier to land on then they are in your pond. Stringing the monofilament in a grid prevents them from moving around in the pond even if they are able to get in in one spot. A monofilament grid will also keep ospreys, eagles and owls out. Unfortunately these solutions do nothing for raccoons, possums or otters.
For those customers who live on one of the local rivers otters can be a problem, and for some of our customers on the Elizabeth River minks are an issue. A small low voltage electric fence will take care of these, usually a single strand about 6” off of the ground. You can get these at Southern States, Tractor Supply or order through Lowes or Home Depot. Depending on the whims of our suppliers we will sometimes have them in stock ourselves.
For herons, egrets, possums, raccoons and neighbor kids we have had very good results with the motion activated sprinklers. They are one of the least obtrusive solutions, but have the disadvantages of needing their batteries replaced about every six weeks and cannot be used in winter when it is below freezing.
You can also use a professional wildlife control company, but mostly they are going to do what we have just recommended, though they can trap and relocate some predators, which you can’t do.
Lotus and water lilies need to be fertilized all growing season, April 15 through September. If you choose to use fertilizer tablets, 3 tablets in a two gallon pot or a lotus pot every 4 to 6 weeks will be enough. The tablet must be pushed down into the roots. Another option is fertilizer spikes. One large spike per lily and two per lotus will feed the plant all season as they are time released.
Lilies do best in 2 to 3 feet of water, but will tolerate anywhere from 1 to 4 feet of water depth. However, splashing water from a waterfall, spitter or fountain should not fall on water lily leaves. Before putting your lilies in the pond you should consider using large rocks as a top dressing. Fish will take smaller rocks off, so using large rocks will protect the plants roots and planting media. Rocks about the size of a small egg will do. You can find this size rock by the bag at your local huge hardware store.
When choosing a spot for your lotus, consider a place where the water level is just above the rim of the pot. Your lotus should never go dry. This insures that water will always be in the pot (and the fish will be out!) If you need to elevate the pot, cinder blocks are NOT an option. Uncured concrete of any kind releases lime into the water and will raise your pH to potentially dangerous levels. We have terra cotta flue pipes or milk crates that are ideal for elevating plants of any kind. They will also serve as a hiding place for your fish if a predator comes calling!
As our season winds down, all plants should be cut back. Decaying plant matter or leaves from trees can in a sense poison your pond water. All pond plant material should be composted if possible.
You will need to cut back the lotus leaves during the season or certainly at the end of the season. Because the stems are hollow, cutting the stem below the water level can be harmful, as bacteria can easily enter the tuber. Be sure to make any cuts above the water.
If you are like us and want to wait until the last minute to cut back your water lily (we have seen them bloom on Christmas Day), no problem. When you do, try to get all of the stems you can.
Wait until after April 15 to fertilize anything, including your water lilies. Your lotus will begin waking up with leaves that float on the water’s surface. The plant is not ready for fertilizer until it has at least one leaf in the air.
Our advice for pond plants will cover topics such as depths for different varieties, fertilizers, and what kinds of potting media to use. Marginals or Shallow Water plants need to be placed in 2”-8” of water. Lilies need to be placed at a depth of about 2’-3’ and Lotus at 18” to 2’. Also, small Lily-like plants such as snowflake or water poppy do well at 12”-16” of depth.
Pot up plants in plastic pots such as the hard mesh pots we use and use clay media. Do not bother buying the expensive aquatic soil you see online and absolutely DO NOT use regular potting soil, or even dirt!!!! They may contain additives or bad things you do not want in your pond water. Using clay is best. The best clay is just plain, unscented, non-clumping NATURAL CLAY cat litter. It’s all clay!
For Marginals, if placing them in the pond as ‘bare root’ plants (meaning in the rocks on the edge of pond) do not place them in more than 2” of water. Keep in mind that “most” marginal plants do better in a bog filter ‘bare root’ OR in small pots with clay and a thin layer of rock on top. Potted marginal plants should be placed in a manner that the roots are under the water line and the stem is growing above the water line (Do not submerge marginals). If you buy our plants already potted up, the depth to place them will be 6” to 8”.
For lily-like plants such as Snowflake and Water Poppy, pot them up in a hard mesh pot with clay and put a thin layer of rock on top. Then submerge the pot in 12”-16” of water. The leaves will find their way to the surface within a few days. For large lilies, pot up the same way in a larger mesh pot that is at least 10” diameter. Submerge the large lily in 2’-3’ of water.
Use aquatic safe fertilizer during the growing season. Pond tablet fertilizer works well for marginals and lily-like plants. Press one or two tablets down into the clay of the pot. Fertilizer spikes work best for large lilies and lotus. Push the fertilizer spike all the way down into the clay. Pond tablets last about 2 months. The fertilizer spikes will last the entire growing season.
There are some plants we carry that do not require potting. They are floating plants such as Hyacinth, Water Lettuce, Parrots Feather, and Fairy moss or Duckweed. Also, there are plants such as Anacharis, Hornwort, and Cabomba that are completely submerged plants you will put in pond without potting.
Remove the hyacinth and water lettuce at or before the first frost. They will die once the first frost hits and it’s best not to let them decay in the pond. Most of the perennial plants will die off and come back in April. A few of the plants have the potential to stay green all winter such as the Rain Lily and Creeping Jenny. As the plants begin to die off you can give them a “haircut”. For taller plants, it’s best to cut above the water line. Otherwise, leave the perennial plants where they are, no need to sink them to the bottom of the pond or bring them indoors.
The selection of plants can vary slightly from season to season based on the availability from our nursery
MARGINALS:
LOTUS, LILIES & LILY-LIKE:
FLOATING PLANTS:
SUBMERGED PLANTS:
How often your pond should be cleaned depends on many factors. The better your circulation and filtration, the less often your pond should need a “full” cleaning. Filtering the pond three or more times an hour, lots of aeration to keep debris from settling on the bottom, lack of dead zones, no gravel to trap debris, and oversized filters or bogs all help keep the pond clean as it goes along, lessening the need for annual cleanings. Your filters should be cleaned at least yearly, but a well-designed pond should easily be able to go three to five years or more without a “full” cleaning.
You can easily clean your pond yourself, however, if time or energy leads you to have a professional do it, here are some things to look for in choosing someone to do your pond cleaning.
A typical pond cleaning should consist of, pumping half or more of the water out of the pond and then catching the fish to put in their holding tubs. Pump the rest of the water out. Use a high pressure hose nozzle or a pressure washer to wash down the side and get any loose debris to the bottom.
Vacuum the debris / muck out of the bottom. Do not try to get the rocks or the liner completely bare, some “slime” on them is beneficial. Completely clean your filter/s at this time. Waterfall filters should be completely emptied and all parts cleaned. Bog filters should be vacuumed out through the standpipes and water even run in from the top to force muck out of the gravel and back into the pipes to be sucked out. Pressurized filters are all different, follow the owner’s manual for them. This is the time to change the bulb in your UltraViolet light, as they are only really effective for about twelve months. Refill your pond, putting plenty of dechlorinator in and be sure to reseed your filter with fresh bacteria / enzymes.
Pond cleaning is usually done in the spring when it is needed, but may just as well be done in the fall. It should NOT be done in the summer. For our area, we do not recommend cleaning be done after the first week in May or before the last week of September, as during that period doing a cleaning puts too much stress on both your fish and your plants, and cleaning your filter when the fish are fully active puts too much load on it as it tries to re-establish itself.
There is much confusion on the internet concerning bogs for your yard and most authors do little to try to explain the differences, resulting in many people building the wrong thing for their situation.
A bog garden is NOT a bog filter. A bog garden is just that, a garden for bog plants and will not act as a filter. It is typically built about 18 to 24” deep, filled with a peat / soil mix, may have drainage in the bottom and may or may not have running water across the top. Great for plants, beautiful but of limited utility for a pond.
A marsh filter is a bad compromise. In a marsh filter you have a liner or tray arrangement filled with gravel or planting medium in which water flows in one end at the surface and then across the top, winding through the plants before discharging at the other end through a pipe or spillway. This does do some filtering, but you get anaerobic bacterial growth in the gravel / planting medium which in turn generates hydrogen sulfide and methane, causing a smell anytime the gravel / medium is disturbed.
A vegetative filter (for lack of a better name) is what we will call a filter in which water runs through a bed of floating plants with no substrate, this might typically be a shallow tank or trough with water coming in at one end, flowing out at the other, through either spillways or pipes with the tank filled with something like water hyacinths. With sufficient flow and plants this makes a very effective filter during the growing season. Unfortunately, here in Hampton Roads, as all of the floating plants will either die back or just die at the start of cold weather, this filter is not a year round filter.
A true bog filter is the best pond filtration you can have, the least maintenance and the prettiest filter. A bog filter with a surface area equal to about 20% of the surface area of the pond and with a flow through rate of at least one and one-half times the pond volume is usually sufficient to filter the entire pond adequately. You should also be sure to have a flow rate of 100 gph per square foot of bog surface. The key element is your water flow. Water should enter at the bottom through a grid plate or a grid of pipes. You want aerobic bacterial growth in your bog filter rather than anaerobic, so you want to avoid dead spots in the gravel where there is no water flow to support aerobic growth.
Towards this end you want your pipe grid to be on 12” to 18” centers with either slots on ¼” to ½” spacing about one third of the way through the pipe, or holes. We prefer the slots facing down, though not all bog installers agree on this point. You can also drill holes instead of slots. Holes should be about three eighths of an inch diameter and no more than an inch apart and on both sides of the pipe. Our recommendation is to then have 10” to 14” of gravel on top of the pipes. If your gravel bed is too shallow, plant roots get down in and plug up your pipes. Too much gravel makes your pump work too hard and adds un-necessary expense. Gravel should average nickel to quarter diameter size, usually referred to as river gravel or #57 gravel (NOT #57 stone). Pea gravel is a little too fine and sometimes plugs up and bigger gravel is harder to plant your plants in. The bog can be done as either a wet bog, that is, a bog with the top two inches or so being free flowing water, or a dry bog, that is a bog where the gravel comes up above the water level by an inch or so. Most people do a combination, with either an area in front of the spillway wet and the rest dry, or a wet meandering stream like area through the bog ending at the spillway and the rest being dry. We also like to put a clean out arm and cap at the end of each of the grid laterals. These clean-outs should be used once a year at least to clean the bog, simply by uncapping and sticking the hose from a pond or wet/dry shop vacuum in and sucking all of the built-up muck and snail shells out.
Plants in the bog should be planted bare root in the gravel for maximum benefit. We like to plant a mix of perennial marginals and evergreen marginals so that you still get some advantage from the plants in the winter. We will add an occasional annual for fun and appearance. We caution against putting some plants that may get too large and restrict flow and crowd everything else out, such as giant papyrus.
As a bog filter is in effect an aquaponics set-up (hydroponics with fish) you can grow almost anything that will grow with wet roots. We have seen success with tomatoes, peppers, and okra. We regularly grow watercress. The flood and drain regimen used for many aquaponic / hydroponic set-ups should not be tried with a bog filter, nor is it necessary for any but a very few leafy vegetable plants. Rhubarb can also be grown in a bog. Rhubarb makes excellent pies. I really like rhubarb pies. Hint, hint.
The better set up your pond is initially, the less you should have to do to maintain it. However, there are certain basics for all ponds, no pond is “maintenance-free”.
That said, here are our recommendations for a properly built and set up pond.
Feed your fish regularly. How much and how often will depend on time of year, temperature, number and size of fish and type of food, but establishing a regular feeding pattern will train your fish on when to expect food and make watching your pond more enjoyable.
Check your skimmer regularly. Ours need to be emptied daily in the spring, about twice weekly in summer and fall, though if you have a lot of trees, count on near daily in the fall, and once every week or two in the winter. Regular checking here will make your pump live much longer.
Add your beneficial bacteria monthly, year-round. Yes, it really makes a difference, even in the winter, and then you aren’t trying to play catch-up in the spring. Adding bacteria to your system just once at start-up helps, but your beneficial bacteria culture in the filters degenerates over time and refreshing it monthly keeps your filter at top efficiency.
Keep an eye on your filter, but don’t try to keep it pristine or clean it too often. Dirty looking is good, it means it’s doing its job. Every time you clean a filter completely you destroy the beneficial bacteria culture and it takes weeks to get back up to speed. This is why we recommend doing filter cleaning in early spring or late fall when your pond is near dormancy and can handle a filter slow down.
Be sure to keep your water level up. It is perfectly normal to lose ½” or so of water a day to evaporation. The more water movement, the more waterfall, fountain or spitter splash and the more plants you have, the more water loss you will see. A cold dry windy day will suck as much water out of your pond as a hot summer day. You don’t need to replace the water daily, but once each week or ten days is probably going to be normal. When adding water, if it is not from a well, be SURE to add dechlorinator to your pond first. I don’t care what your brother-in-law said, he’s wrong, it will too injure your fish! Even a small amount of chlorine / chloramine in the water will chemically burn your fish’s gills and affect their long-term health. Always add the dechlorinator first, before you add the water. Removal is virtually instant, so you can put the hose directly into the pond after the dechlorinator has been added.
Test your water monthly. The pH is the most important test to do regularly. We frequently hear “I haven’t tested mine in years and it’s been fine.” Used to be, but in the last several years the acid rain has gotten so bad that on average we now get at least one customer each WEEK coming in with sick, dying or dead fish and when we check the pH it has crashed from the acid rain. It’s simple to keep an eye on it. Test your salt level at least three or four times a year also. Ammonia testing is important mostly with a new pond, one that has just been cleaned or had its filter cleaned, or one that is overcrowded in hot weather.
Trim your plants as needed. Most pond plants are constantly sending out new leaves during the growing season as old leaves die off. Removing the old leaves helps the skimmer, the filter and the general appearance of the pond. Don’t panic or go overboard on this one though. Your pond can handle some dead leaves without it becoming a crisis.
Twice a year, early spring and late fall you should dose your pond with a broad spectrum disease treatment for the general health of your fish and pond.
Be sure to change your ultraviolet bulb EVERY year, early spring is the best time for this.
If your pond is set up properly with lots of water flow, lots of filtration and aeration and you take care to keep leaves out in the fall, it should not need to be cleaned every year. Every third or fourth year is fine, and we go ten years or more. The key deciding factor will be debris build up on the bottom. If you have debris build up, clean your pond. Then redesign the pond so it doesn’t happen again.
Pond care books tend to be written so that they can be used from Maine to California. Much of what they say in the way of seasonal advice does not apply to us here in Hampton Roads.
Lotus and water lilies need to be fertilized all growing season, April 15 through September. If you choose to use fertilizer tablets, 3 tablets in a two gallon pot or a lotus pot every 4 to 6 weeks will be enough. The tablet must be pushed down into the roots. Another option is fertilizer spikes. One large spike per lily and two per lotus will feed the plant all season as they are time released.
Start feeding your fish with fall food (wheat germ) in late September. This will allow your fish to build up their fat reserves for the winter. As the temperature drops, slow down their feeding schedule. Stop feeding your fish entirely at Thanksgiving and start feeding again at St. Patrick’s Day. Use our feeding chart and the water temperature to determine how often to feed until Thanksgiving. Keep in mind that your fish need at least two weeks for their metabolism to speed back up to the point where they can safely eat. Two or three days of warm weather in the winter does NOT mean that you can feed your fish, even if they beg for food and “well, the book says I can feed them if the temperature is over 55”. Remember, your kids want to eat the whole bag of candy at Halloween, but if you let them, they will get sick.
We strongly recommend a fall (and spring) parasite treatment for your pond. Parasites can enter your system on plants and from birds using your pond for bathing/ drinking. Treating twice yearly to prevent infestations will help keep your fish healthy for years to come. Continue to add beneficial bacteria to your pond monthly all winter. Take advantage of this time to check your salt level and adjust it for the winter. (About .1% to .15 % for a pond with plants.)
As the temperature drops and your plants start to die back, cut all dead leaves off. Some plants will stay green all winter in our area, so only cutback leaves as they turn brown. Do not pull out and remove the root masses in your waterfalls or stream beds, as these will come back next year. At the first frost, throw out all Water Hyacinths and Water Lettuce. With our mild winters, it is not necessary to move plants to the deepest part of the pond. Inspect their pots so that you can plan what plants to separate come spring. Repot into mesh planting baskets. We carry many different sizes.
If your pond is located under or near trees, we recommend putting netting over it to catch the leaves, as this is easier than scooping them out daily. Leaving leaves in the pond will add tannic acid to the water and give your water a dark iced-tea appearance. They will overload your bio filter as they break down. Fall is also the second most likely time to have visits from herons, spring being the first, so the netting will protect your fish. Put your netting up in such a way that it is supported in the middle and does not sag into the water. Even though some netting advertises itself as “floating” it should not be in contact with the water. Leaves on it will still release their tannic acid into the water and your koi can cut their mouths on floating netting.
Make sure your pumps and filters are operating properly, but with a waterfall filter or other large bio-media filter, wait for January or February to clean the bio-media. Leave your pumps running all winter, except for days where your pond is actually frozen over. Our more northern customers (Williamsburg, Gloucester, Mathews, New Kent) or those with small ponds of 400 gallons or less may want to use a pond deicer. Most ponds in Hampton Roads proper won’t need one for a normal winter. When ice forms on your pond, leave it alone unless it looks like it will stay for more than a day or so. If it stays, use very hot water to melt a hole in the ice. Do not break the ice, as the shock can harm your fish. If you don’t have one, consider adding an aeration system to keep a small area of your pond ice free even if you should have to turn off your main pump.
Though any time is fine for adding fish, fall, as the fish begin to go dormant, is actually the absolute best time to add new fish, causing them the least stress.
If you opt to clean your pond or have it cleaned, it can be done in either late fall or early spring, while the plants and fish are both dormant. We can rent you a pond vacuum and holding tanks if you want to do it yourself.
There are at least three basic types of pond, the natural in ground pond, the formal / semi-formal in ground pond and the raised pond, which by it’s very nature tends to be formal or semi-formal.
Most of our planning recommendations will apply to all three styles. Our very first recommendation is: Make it bigger. We have yet to hear from a customer telling us that they wish they had made their pond smaller. Almost everyone comes in sometime in the first year or two and tells us they wish they had made it bigger. Remember, doubling the size does not double the price. Also the larger the pond, provided it is done correctly, the LESS work it is to maintain. The bigger a pond is, the more it acts like a self-sustaining ecosystem.
Next, after you decide on the type of pond and rough size that you want, you need to decide on location and orientation. Ask yourself, when sitting outside enjoying the pond, just where you will be sitting. Put the waterfall opposite from there so that you look at the falls. If you are going to be sitting on a deck, don’t back the falls up to the deck.
Now, where is your electric service for the pond? It should be at the other end from the falls. If running new or upgrading, you should have your electrician give you at least eight outlets for any pond over 1000 gallons, and this is absolutely necessary for any pond over 3000 gallons. Ideally, this would be two 15 or 20 amp circuits with four outlets on each circuit. You won’t have a lot of power consumption on the circuits, as most of what you will be plugging in is very low draw. Why eight? With a 3000-gallon pond you have at least one, possibly two main pumps. You have two ultraviolet lights. You should have an air pump. You will probably add underwater lights at some point and maybe a spitter or fountain. Wow. We just used up seven of our eight outlets.
You will automatically have this with the raised or formal pond, but with the natural pond it is of critical importance to have the edge slightly raised above ground level. You can feather this berm so it is not noticeable, but you do not want runoff from the yard to go into the pond bringing with it pesticides or fertilizers that have been put down by you or any of your neighbors.
On the natural pond we also recommend you dig a shelf about 12” deep and about 15” to 18” wide all the way around the pond. This gives you a base to stack rocks on to hide the liner on the edge of the pond. Plants can also then be planted bare root in these rocks.
Now to the materials. We will only sell and only recommend 45 mil U.S. made EDPM rubber liner.
Hard plastic shells don’t last and are too hard to install correctly. PVC liners only last 7 to 10 years. 20 mil liners cut or puncture too easily. The Chinese made EDPM doesn’t hold up over time. (Yes, I tried it once. Had to replace it three years later. Learn from my mistakes!) To size your liner, start with your widest width. Add the deepest depth. Add the depth again. Add 1½’ for the overlap on the side.
Add 1½’ for overlap on the other side. This is the width of the liner you need. Now do the same for the length and this is the size liner for your pond. We recommend a maximum depth for this area of 3’ to 3½’. You may read books or articles saying a pond should be deeper, but that applies to much further north than we are. For winter weather here, 12” is deep enough, but we recommend the 3’ depth for predator protection and coolness in the summer. We do recommend use of an underlayment. We sell it by the foot off of a roll but many people just use old carpet instead. We have seen sellers say not to use carpet, that it will rot, but we have worked on and pulled up 20 year old ponds where the underlying carpet was still there. Many books will tell you to use sand under your liner to level and pad. We vehemently disagree with that. Sand is abrasive. Use peat moss. It’s soft and fluffy and compresses well and won’t wear a hole in anything.
Pumps. Once you know how big your pond will be you can size your pump. Absolute, absolute minimum is to filter your water at least once an hour. Keep in mind that pump ratings are before figuring head pressure, so a 1500-gallon pond should have at least a 2000 gallon per hour pump.
More is better. We filter our display pond and most of our holding tanks six times an hour. We will try to talk you into a pump or pumps that will filter your pond two or three times an hour. The two big differences between good pumps and cheap pumps is, one, how long they last (We have many pumps here that have been running for ten years and more) and, two, how much power they draw. If you save a hundred bucks buying a pump that costs you an extra 10 bucks a month in electric to run, you haven’t saved anything. Years ago, external pumps were more reliable and efficient, but over the last fifteen years or more, submersible pumps are now both more reliable and more efficient. For larger ponds we recommend two medium pumps rather than one big one. Two 5200 gph pumps use less electricity combined than one 8000 gph pump by itself, give you more total flow AND give you some redundancy so you still have filtration even if one pump goes out.
Again, depending on which type of pond you have decided to go with, you should plan for either a waterfall filter, a bog filter or a pressurized filter. What is most important is that it is big enough for your pond. Realize that all manufacturers over-rate their products. (Ford says my truck gets 23 mpg. Yeah, right.) We generally say start at about two-thirds of the rating as being more realistic, and again, you can never have too much filter. We have a nice separate write-up on filtration for you to refer to.
We strongly urge you to use a skimmer. It will make pond maintenance easier and thus pond ownership more enjoyable and will help your pump last years longer by better protecting it. Skimmers come in all prices and qualities. We recommend the Savio as far and away the best designed and best made available. It is easily many times better than any others on the market. If you want a cheap piece of crap, go on-line and buy it, we won’t sell it to you. The Savio skimmer also has the advantage of allowing you to install uv lights directly in the skimmer, saving plumbing hassles, making for a more elegant and better looking installation and making changing the bulbs easier.
We cannot emphasize too much how much we strongly, strongly urge you to install an ultraviolet light on your pond. We have no tank or pond at our shop containing fish that we don’t run a uv light on. If sized and installed correctly, they not only help control green water algae but help to cut down on any disease organisms in your pond.
With a typical medium to large pond you will have a skimmer at one end pulling water off of the surface and your waterfall / bog / pressurized filter putting water back in at the surface at the other end, filtering the top foot or less of water over and over as the bottom becomes gradually dead, de-oxygenated and collects debris. By adding an air pump and airstones you create a series of currents pulling water and debris off of the bottom and up to the surface where it gets aerated and filtered. This can also be accomplished with bottom drains, but we do not recommend them as they are more expensive, the plumbing to install them far more complex and because you are penetrating your liner in the bottom of the pond you have a serious danger of an eventual leak.
When designing your plumbing remember not to use sharp 90° turns. Best is flexible hose that can do a wide sweeping curve, next best would be to use what is called a sweep 90° fitting or use two 45° fittings in a row. Every hard 90° fitting in your plumbing will cut your flow rate by 5%. Measure your estimated piping for both total length and height of rise. This will give you your head pressure to use in sizing your pump. Every foot of height difference between the surface of the water and the height of the spillway (not where the water enters but where it leaves) is one foot, then every ten feet of pipe length equals another foot of head pressure. Get this total, then check it against your pump manual to see how much water to expect at this head pressure. Then subtract 5% of that figure for each 90° fitting and 2% for each sweep 90° or double 45° to get your actual pump volume. For pumps up to about 2000 gph you need at least 1¼” hose / pipe, for up to 3500 gph you need at least 1½” hose / pipe and for over that you need at least 2” hose / pipe. Too small a hose / pipe will put excessive back pressure on your pump and seriously reduce your achievable flow.
We will be happy to go over your design and materials list with you before or during construction and give you our advice on it. Our goal is for your pond to work well and be as easy as possible to take care of so you spend your time enjoying it instead of fighting with it.