Updated: Jun 19
If you’ve clicked on this article, you either purchased a home with a koi pond, just had one installed, or you’re thinking about getting one. For the purposes of this article, I’ll be discussing the basic maintenance of ecosystem ponds. Though similar, this is not meant for ponds that are considered natural or “mud-bottom”, or ponds that are considered “koi museums”.
Your new pond is considered an ecosystem pond if it has the following 5 components: a mechanical filter (called a skimmer) where it holds the pump for circulation, a biological filter (usually a waterfalls), rocks and gravel (these hold down the liner), plants (waterlilies and marginals in the water), and fish such as koi or goldfish. In the past few years I’ve seen many variations following these same 5 components; however, you likely have an ecosystem pond. Whether or not it needs upgrades or was built properly in the first place is another story.
The first questions you should ask yourself are: Does the pond pump work? Do I have any fish in my pond? How do I add water to my pond? How do I keep my pond clean?
As for the first question, that is relatively simple. Your pump should be located in a skimmer box. Look along the edge of the pond (ideally opposite the waterfall), you may find a plastic box that is buried into the ground. The pump should be in there. If it is, find the cord and plug it in. If the pump works, you should hear the waterfall running in about a minute or so. If the pump doesn’t work, you either won’t hear anything, or you may hear a loud grinding noise. If the pump sounds like it is gurgling water, look inside the skimmer box. If it looks like the water is going down to the pump it is likely sucking air. This means you have to add water to your pond.
Adding water to your new koi pond is pretty simple. You find a hose, connect it to your hose spigot, and turn on the water! If you are on city water (tap water) you’ll need to add a detoxifier, or dechlorinator. These products (usually a liquid in a bottle) neutralize the chlorine in the tap water, they will often detoxify heavy metals also present in the water. If you are on well water, it is typically recommended to add an ammonia neutralizer (a dechlorinator isn’t needed because your well water isn’t treated by the city - usually). Well water might have ammonia in it, so this helps make the water cleaner for the pond. Both of these products can be purchased online, or at a local store dedicated to ponds. Some aquarium stores carry pond products; however, they usually don’t have large enough quantities for my own personal satisfaction so I hesitate to recommend them. The individual reader will need to learn their local stores to get a feel for his or her own satisfaction. You may also be in luck and have a contractor near you who can provide these products for you (*hint* they might have a retail store, or retail capabilities)!
This brings me to my next topic, understanding what the nitrogen cycle is and why that is important for your plants. To put it simply, I will mention this: decaying organic matter (leaves, sticks, fish waste) gives off ammonia. In high amounts this is toxic for your pond inhabitants. You’ll need beneficial bacteria to eventually convert this ammonia to nitrite (also toxic) which then is converted to nitrate. Nitrate is the least toxic part of this nitrogen cycle. Fortunately, nitrates are taken up by the pond plants as a natural fertilizer. For a more in-depth discussion of the nitrogen cycle, subscribe below as I will be coming out with a dedicated article in the future.
This is where the importance of the beneficial bacteria comes to play. Many different products are available, they are found in a liquid form, or in a dry, dormant, form. I’ve even met people who let their pond get bacteria naturally and haven’t had serious problems. I definitely don’t recommend this as you need to be well-versed in water chemistry and understand how the fish population impacts your water quality. My favorite way to dose the beneficial bacteria is throughout the pond. I will put most of it into the skimmer box to be pumped into the bio filter. In the waterfall filter are usually mats on a rack, and on top of those are usually some sort of media for bacteria to colonize onto. This media is usually lava rock, gravel, or plastic bioballs; some other concepts use ceramic media. The rest of the beneficial bacteria I like to place where the waterfall enters the pond. This will help disperse it amongst your boulders and your gravel. These boulders and gravel are important as they also provide surface area for bacteria to live on, and they provide shelves and pockets for aquatic plants to grow within. I once heard it said, koi and goldfish living in ecosystem ponds are living well because the pond is the filter!
The next question the beginner, new pond owner should be asking is, do I even have fish!? If your pond is super brand new, I certainly hope you don’t have fish. It can easily take 4 to 6 weeks for a biofilter to get established, even more if you plan on having a lot of fish (this is known as a bioload). If your pond is brand new and you do have fish, just know that dosing the beneficial bacteria more often than recommended is a good place to start. In these instances, I usually recommend to dose it twice as much as recommended by the manufacturer.
If your water is too dirty or murky to see whether you have fish, it definitely needs to be cleaned. Your local pond contractor may offer a service known as an exploratory pond cleanout. These are cleanouts that are specially suited for ponds that are already existing when the new homeowner moves in, and when the pond is unknown to the contractor. The thorough contractor will perform not only a deluxe pond cleanout, they will also inspect your pond and inform you what brand of products you have (biological filter, mechanical filter, pump, lights, etc.), and take approximate measurements (length, width, depth) which will provide an estimated water volume (typically anywhere from 800 to 2,000 gallons). We at Good Steward Ecoscapes will happily perform this service for you, if you have no idea where to start and are not willing to do it yourself!
The water volume is one of the most important things to know about your new pond because it drives how much water treatment to use. The biological filter is first established by appropriately dosing the beneficial bacteria to the size of your pond. Water treatments of various kinds (algae control, fish health, water clarity, sludge control, etc.) are all based on the water volume in gallons or liters. Only larger systems such as retention ponds or mud-bottom ponds will use measurements based on surface area!
The last and arguably the absolute most important thing to know about your new ecosystem pond is it uses natural filtration methods, meaning it is safe. The water treatments used in ecosystem ponds are environmentally friendly. Unlike a swimming pool, the water is naturally filtered with the beneficial bacteria and the plants. The eco friendly treatments and the lack of harmful chemicals means the wildlife in your backyard have an oasis to thrive in. This is a concept we refer to as Living Water, or Aqua Logos. The clean water will mean you will find a new hobby in bird watching as the birds dive down to drink along the pond’s edge. You will have frogs and toads, it will attract dragonflies, and thankfully, you will have fewer mosquitoes! This is another concept we refer to as “Backyard Conservation”.
These ponds are safe for your dogs, and they are safe for your children or grandchildren. You will spend hours and hours enjoying making memories with this new part of your life. Welcome to the pond hobby, it is one of the most relaxing and rewarding hobbies one can find. I might be a little biased; but, I do love my pond.