Maintenance and Troubleshooting
The great thing about a natural pond is that regular maintenance is almost nonexistent. Top up the pond when it needs water. Add a bubbler in winter if you have fish. Spend an hour a year taking out some organic matter. Sit and enjoy the pond.
If you read other pond instructional books or search the internet, you’ll find all kinds of things you need to do to keep a pond healthy. That advice might be right for the pond design they use, but it is not applicable for the natural pond design described in this book. You can skip most of that advice.
This section describes routine maintenance tasks for other pond systems that are not required for natural ponds. They are included with explanations for why you don’t have to do them.
Because fish and plants have a preferred range of pH that they need in order to live, it makes sense to check that its level is right. The problem is, what do you do if it is wrong? As different biological processes become more dominant, pH fluctuates. Warm days will have a different pH than cold days. Early in the season will be different from late in the season. How often are you going to try to control this?
The only way to control pH is to use chemicals. Once you start adding chemicals to control pH, you will need to continually check it and keep adding chemicals—a never-ending process. Each time it rains or you add more water, you need to check the pH and adjust it. I strongly believe that continually changing the pH level is worse for life in the pond than leaving it alone.
It is very unlikely that your drinking water has such an extreme pH that it will not support fish and plants. It may not be ideal, but it will be satisfactory. If you drink the water, the fish and plants will be fine.
Regular pond care requires that you add bacteria to keep the filters charged. In spring you add them to get the filters going. In fall you are supposed to add special bacteria for cold weather. If the pump is turned off for a while, the bacteria in the filter die and you need to add more when you restart it. Many people add bacteria twice a week—just to be sure.
Some of this might be beneficial if you have a complex filter system or have too many fish. Otherwise, adding bacteria makes no sense. They find the pond on their own, and they don’t die off that quickly. If environmental conditions turn against them, they go into a type of hibernation until the conditions are favorable again. A natural pond is full of many different types of bacteria. Some grow better in warm weather and some in cold weather. You don’t need to add more.
Fish waste contains a lot of ammonium (same as ammonia). If the levels get too high, the fish can die. So some pond owners are constantly checking to make sure they are safe. If levels get too high, they add a handful of bacteria to solve the problem.
The alternative is to keep fish levels lower and don’t add food, so you never have this problem. High ammonium levels are the result of too much fish poop. If you control the poop levels, you will not have ammonium problems.
Ammonium is also converted to nitrite and nitrate by bacteria (see figure 2). A natural pond design has plenty of microbes to take care of any ammonium produced by fish. It does not need to be checked.
Fish breathe oxygen, and if the levels get too low, they can suffocate. This will not happen in a pond with a normal number of fish, but some people cram a lot of fish into a small pond for a better display. They artificially create a situation where it is very easy to run out of oxygen. In this case, you need to keep monitoring the oxygen levels. If they get low, you turn on auxiliary pumps and fountains to increase the gas exchange between water and air. An alternate solution is to have fewer fish.
After a few months or a year, all of the surfaces in the pond become covered in slime. To the uninformed, this is a bad thing, and they want to clean it out. Many maintenance schedules call for you to empty the pond water once a year in order to scrub the sides of the liner and remove the slime. Once the pond is crystal clear, you refill it and dump in some purchased bacteria.
What these people don’t understand is that the slime layer is made up of microbes, including bacteria. They need to add bacteria to the water because the cleaning process just removed them all. This makes no sense. Just leave the beneficial slime in place and go have a beer.
Natural ponds do not need to be cleaned on a regular basis. Instead, you do everything you can to grow as much slime as possible. In our ponds, the slime is our natural water filter and pond cleaner. My pond is almost ten years old and has never been cleaned. The water is crystal clear.
Algae growth is a big problem with pond owners since they don’t like the look of it. The simple solution is to add algaecides that will kill the growth. This works—to a certain point. The dead then settle on the bottom and start to decompose, which releases nutrients into the water that feeds more algae growth. No problem, add more chemicals.
In these types of ponds, the algae problem is never solved. It recurs several times a summer, year after year. A bigger pump and better filtration system might help. In a natural pond, you will get some algae especially in the first couple of years while the plants are getting settled. The first summer after putting in my pond, the water was a solid pea green color due to algae. I lived with it. It did not harm any life-forms in the pond and gave the fish lots to eat. As plants got established, the algae stopped growing. Three years after putting in the pond, it had almost no algae, and it has been clear ever since. If your algae problem persists, add more plants or reduce the number of fish. Algae will not grow without sun and nutrients.
Water will evaporate from your pond, and the level will go down. How fast does this happen? It depends on many things. Warmer days evaporate water faster than cold days, so the drop in level is very much dependent on climate and time of year. Plants give off water as they photosynthesize. More plants will evaporate more water. The amount of daily precipitation has a big effect on water levels as does any source of inflow.
Keep in mind that spring and fall rains usually top up ponds that then dry down during the summer. If you add water, don’t do it before the spring rains are finished, or you might add too much.
The design of the natural pond is such that the pond can lose several inches of water without any problem. It still looks natural at lower water levels. Once the roots of your plants get too exposed, you could add some more water. My zone 5 pond usually gets topped up once in late summer, and I don’t add too much water because we get fall rains. It has no natural sources of water except for rain and snow.
If your tap water is highly chlorinated, consider adding smaller amounts so that chlorine can evaporate. Too much is harmful to plants and animals. Spraying the water in a mist from the end of a hose will also help dissipate chlorine.
Although all water contains some salts, hard water can contain a lot. As water evaporates, the salts are left behind. This is why your kettle gets a white hard layer in the bottom—these are the salts left behind after water boils off. The same thing happens in a pond. Over time the amount of salt in the pond increases as more and more water evaporates. These salts are mostly made up of calcium and magnesium, which plants use to grow but only small amounts are needed. If you have hard water, partially empty the pond every few years and replace it with fresh water. The frequency of doing this depends on the hardness of your water. Because mine is fairly hard, I replace half every five years. You could get more scientific than this and measure the conductivity of your water, but it is not really necessary, since calcium and magnesium are not very toxic to plants or animals.
Organic matter in the pond comes from falling leaves, dead material from pond plants, and even dead microbes. This all collects at the bottom. You will find that the water in your pond is quite clear and has no real odor. If you disturb the muck at the bottom, the water will get cloudy and stink like rotten eggs. The smell is due to the anaerobic decomposition taking place in the bottom of the pond.
A natural pond can handle a certain amount of organic muck. As it accumulates, it is decomposed, and the nutrients produced are absorbed by growing plants. It is, however, a good idea to limit the amount of organic material collecting in the pond. Having less muck is always a good thing.
If you have a lot of muck, remove it once or twice a year. Fall is a good time so that you can also remove the newly fallen leaves. Just use a pond net and take out most of the stuff—you are not trying to get every last bit. The muck you remove makes excellent mulch for the garden. In eight years, I have never cleaned out my larger pond, but I do clean out the smaller one annually. It has fewer plants so it can’t handle as many nutrients, and it collects a lot of leaves from surrounding trees.
What about the rotten egg smell? Does this not harm fish or microbes? It will harm them if there is too much of it, but it is normally not a problem. It does become more of a problem in winter when the ice prevents exchange of gases with the air. Keep in mind that anaerobic decomposition is a natural process that occurs at the bottom of all native ponds, where no one removes the leaves and muck.
As plants grow, they take up nutrients from water. Many of these plants are perennial, which die back in fall, and all of their leaves drop into the water. For some plants like cattails, the old leaves stay standing all winter. It is best to cut off this material and keep it out of the water, reducing the amount of nutrients in the water for next year.
Ponds in zone 7 or warmer rarely freeze over to any extent, and winter care is the same as summer care—you have nothing to worry about. There are special considerations for areas where the weather is cold enough to freeze the surface solid for two weeks at a time. Provided you select hardy plants, they will survive the winter with no extra care. Special winter care instructions for non-hardy plants are described in the chapter about plants.
Most fish can survive in a pond provided it does not freeze solid. Water cannot get any colder than 32°F without freezing. So even in subzero temperatures, the fish are at 32°F or warmer. But fish can suffer when the pond is covered with a solid piece of ice because it prevents the exchange of oxygen and CO2 at the surface of the water. With an ice cap on the water, the oxygen level decreases while the CO2 level increases, and the fish can suffocate. Most fish deaths in a pond are due to a lack of oxygen, not cold temperatures.
The easiest solution is to keep the surface of the water from freezing solid. The goal is to have at least a small opening in the ice for the gases to exchange with air. This can be done in two ways. Moving water does not freeze as easily as standing water. One way to keep it moving is to add an air pump and bubbling stone. These common supplies are sold at pet stores. Just place the air line into the water and anchor the air stone so it is below the surface of the water. Run the pump continuously during the cold parts of winter. The air pump works fine in zone 5, unless we get really cold temperatures for two consecutive weeks. Even with a bubbler going, the surface can freeze over.
A second option is to get a pond deicer or heater from pond supply houses, or you can make your own. (Some DIY solutions are included in the References section.) They float and keep the water around the heater warm enough so that it does not freeze. As long as the ice is not frozen solid, CO2 and oxygen will exchange with the air and keep oxygen levels in the pond high enough for your fish.
The bubbler and heater can be combined to give even more protection. They don’t need to be in the pond all winter, only when very low temperatures last for several days or a week. In zone 5, that is normally a six-week period.
Even if you don’t have fish, you might think about keeping the surface of the pond open all winter. Frogs, who overwinter in your pond, have the same breathing problems as the fish.
The pond owner’s worst fear is getting a leak in the liner. The good news is that if you use the recommended rubber pond liner and you followed the construction recommendations in this book, this is very unlikely. Most so-called leaks in a lined pond are due to water flowing over the edge of the liner, not holes in the liner. This is a bigger problem with streams and waterfalls because water runs near the top of the liner. Ponds are normally designed so the excess water only flows out the spillway and never gets near the edge of the liner except at the spillway.
How do you know you have a leak? It may not be obvious if the leak is small. The water level will drop a bit faster than normal. But what is normal? If you get a week of hot, windy weather, evaporation will be higher and the level will drop faster than normal. It always drops faster in mid-summer. So there really is no normal. It is something you will get a feel for over time.
Before a leak occurs, you can measure your evaporation rate. Put a mark on a stone or on a dock post. Make another mark a week later and measure the difference between the lines. You then know how fast the water level drops at that time of year. Record that number for future use.
If you think there’s a leak, you should first go around the perimeter of the pond and make sure the edge of the liner has not slipped down below the water level. If it has, pull it back in place and support it with rocks or soil. You have solved the problem.
If that did not help, drop the water level so it is definitely below the spillway. If water is no longer leaking out, then you have a problem at the spillway or somewhere around the outside of the pond above the current waterline. Since the leak stopped when you dropped the waterline, you know the leak is now above that. Check to see that water is not running under the liner at the spillway. If the spillway is OK, then check around the outside of the pond for a leak above the current waterline.
If you still have not found the problem, there are two ways to proceed: a slow way and a fast way. The slow process is easier, but slower. You just wait until the water level starts dropping at the normal speed. When it reaches this point, you know that the leak is just above the current water level. Check all the way around the pond right at the water level. You are looking for a hole. A larger one made by animals will be easy to see; a smaller one can be difficult to find.
A quicker way to find the hole is to drop the water level one foot and see if you are losing water. If you are, drop the level another foot. Keep repeating this until you stop losing water. At that point, you know that the hole is somewhere in the foot above the current waterline. Check all the way around the pond until you find the hole.
In order to see a hole in the liner, you will have to remove any stones or protective material hiding the liner. That is a lot of work, and it is why I recommend adding a protective layer both above and below the liner and why you should only use the best rubber liner for the job. A well-constructed pond is not likely to have a hole.
Finding the hole in a pond liner is the hard part. Fixing it is easy and can be done without removing the liner from the pond. Obtain a pond liner repair kit and follow the instructions, similar to repairing a punctured bicycle tire. Once it is dry and sealed, you can refill the pond. The patch should outlive the rest of the liner.