Does A Koi Pond Need A Bottom Drain?

If you own a koi pond, you already know that the most time-consuming aspect is keeping it clean. Although an increasing number of individuals understand the advantages of employing a bottom drainer in ponds, many wonder if it is genuinely required. In light of that, is it necessary to install a bottom drainer in your koi pond?

A koi pond can successfully operate without the use of a bottom drainer. However, not using a bottom drainer would require you to use alternative methods to clean your pond, such as vacuuming, as an example. On the other hand, installing a bottom drainer would have plenty of advantages.

In most ponds, bottom drains function in tandem with the filtration system to remove debris and maintain the water clean for the koi. Sediment accumulates at the bottom and is pushed down the drain by the force of the water. With that in mind, let’s take a closer look into why many individuals would get a bottom drainer for their koi pond.

Pro Tip: If you’re tired of wasting money and making costly mistakes on the koi-keeping hobby or are thinking about buying koi fish but don’t know where to start, I strongly suggest you check out this ebook. I recently read this ebook, and it contains SO much useful information, such as: 

  • 3 proven steps to identify koi fish diseases
  • WARNING: 3 things you should NEVER do when it comes to caring for koi
  • When to seek professional help when it comes to looking after your koi

Click Here Now To Check It Out

What Is A Bottom Drain, And Is It Required?

A bottom drain, often known as a bottom filter, is a drainage device capable of sucking up material such as leaves while vacuuming the pond. A pond or water garden is best compared to a holding tank or cage. While the fish are present, the last thing you want is muck to break down and accumulate within it.

A bottom drain keeps the water clean by adequately handling the muck. Bottom drains are particularly effective since they contribute to aeration while requiring less maintenance.

Many contractors clean ponds in the spring and autumn, and these drains, paired with an excellent external pump and pre-filter, make their duties much more accessible.

Gravity Fed Pump Return Filtration is the conventional name for this setup. Furthermore, it is a very efficient configuration, and there are several reasons why this strategy is superior to other options.

For starters, water is being drawn from the very bottom, where dirt would ordinarily build, preventing the formation of a sediment layer.

The water flow through the drain and piping is smooth, so the fine particles created by the fish are not broken apart. It indicates that the filter is eliminating larger materials rather than finer ones. On the other hand, large solids are simpler to settle or sift out of the filter.

The plumbing is buried using a bottom drain system, and no electric lines are running through the pond. As a result, it appears more professional, and there are no pipes or wires retaining silt to prevent you from vacuuming the bottom.

Bottom drains are also energy efficient since they may be pushed back into the pond using a low-wattage circulating pump.

Because there is no lifting of water, establishing the flow requires less energy. In addition, pumps have a longer lifespan and require less maintenance because the water going through them is clean and free of solids.

Overall, I can certainly declare that installing a bottom drain is the single most crucial step you can do while constructing your pond.

How Does A Bottom Drain Installation Work?

The majority of bottom drains may be used with a skimmer. The valve must be placed within the skimmers to control the flow rate. The optimum way is to connect the drain to the pre-filter to supply filtration and drain efficiency.

One thing to keep in mind during installation is that in most circumstances, an aeration unit with a sloped bottom will be preferable, as gravity will drive the pond muck downward.

They are particularly effective when the suitable sized drain is chosen and fitted with the proper equipment. Bottom drains will not only clear your pond of waste, but they will also help maintain the water cleanliness without requiring you or a pond contractor to perform any work. Again, your fish’s health and survival depend on it.

Why Don’t All Ponds Get Fitted With A Bottom Drainer?

When a pond is built, bottom drains and the associated plumbing are usually installed. Retrofitting a drain is occasionally achievable, but it might not be accessible depending on the conditions. In addition, people are often hesitant to install a drain because they are concerned about it being sealed into a liner.

On the other hand, sealing it on a liner is a relatively straightforward process, and most experienced Koi pond owners claim to have never had a problem with the issue. Furthermore, the drain features a silicone-covered flange screwed down to the pond liner to provide a watertight seal.

Koi Pond Building Basics

Koi are thought to bring success and good fortune. Whether this is true or not, koi will provide a burst of whirling color and a soothing presence to your yard. Furthermore, because koi are incredibly resilient, they require very little care.

With a koi pond, you’re creating a home for live animals as well as a garden pond. Therefore, the koi’s demands determine many parts of the pond. That said, to get a better understanding of all the requirements towards building a successful koi pond, let’s jump straight into the basics.

Pond Depth Is A Requirement

While categorized as a coldwater fish, koi do not always prefer cold water. They also don’t perform well in really hot water. Therefore, maintain a moderate water temperature of 59°F to 77°F.

Koi can control their temperature at the proper pond depth. For the koi to descend and keep cool in the summer, the pond should be at least 3 feet deep. Lastly, your koi will be safer from predators in a pond that is deep enough.

The Dimensions of a Pond

A large pond is required for large fish. Your pond should be as least 1,000 to 1,500 gallons for five koi. If you have ten or more koi, you’ll need more than 3,000 gallons of water.

Consider a 3,000-gallon pond to be an 18-by-24-foot size with a 3-foot depth. Even if you scale down to a 1,000-gallon koi pond, the 3-foot depth is required because koi require deep water. Therefore, the pond’s dimensions would be 6 feet by 8 feet at that depth.

The Location Of The Pond

Putting your pond in the right spot affects the koi’s health, the quality of the water, and your enjoyment of it.

Keep the pond close enough to the home so you can use the hose from the house’s exterior faucet to fill it. An outside electrical outlet is also accessible from the side of the home. The closer the pond is, the more likely it will be maintained regularly.

Consider how much sun and shade there is throughout the day. Algae grow quicker in full sun ponds than in shaded ponds. It’s also beneficial to the koi to maintain the water temperature reasonably.

Tools Required To Build your Koi Pond

Now that you have the location, dimensions, and depth in mind, it’s time to get to work. First and foremost, you’ll need to ensure you have all the necessary tools.

That Equipment And Tools Required

  • Tape measure
  • Shovel
  • Marking paint
  • Backhoe (optional)
  • You can use either a garden hose, rope, or spray paint to map out your pond.

The Materials Required

  • Mechanical surface skimmer
  • Settling chamber
  • 45 mil EPDM liner
  • 4-inch drain
  • 4-inch flexible hose pipe
  • Biological filters
  • Decorative stones

Guide To Building Your Own Koi Pond

Now that you have all the tools, equipment, and materials on board, you can take it to the next level by taking the following steps.

Step One: Lay Out Your Pond

Trace the primary edges of the pond with a garden hose or rope on the ground, or you could even use spray paint. In general, as the fish develop, you’ll want to scale the pond up to accommodate them.

But, of course, it also creates extra space if you want to add more koi. Again, however, play around with different forms to best suit the style you want.

Step Two: Begin Digging

To reach the needed depth, dig the pond by hand or using rented heavy equipment. Instead of building lofty sides, terrace them by 5 to 7 inches every step. Due to the size of the koi pond, it’s strongly advised that you employ someone or a company to dig the hole using a backhoe or mini-excavator.

Step Three: Add A Drain

Create a drain at the pond’s lowest point by trenching it out. It is where you should run the flexible hose pipe. Furthermore, bottom drains are optional, but they have a considerable advantage in maintaining your pond as they remove a lot of extra work out of the way in the long term.

Step Four: It Is Time To Add The Pond Liner

Unfold the EPDM liner with the assistance of a friend and fit it closely to the pond’s contours. It’s easier to do this on a hot day since the EPDM is more malleable. The liner should reach at least a foot beyond the pond’s edge.

Step Five: Add Your Decorative Stones

Install smooth stones along the pond’s bottom. Place bigger flat stones on the bank to keep the liner’s edges in place. Because EPDM deteriorates more quickly when exposed to sunlight, make sure all exposed areas are covered.

Step Six: Install The Setting Chamber

The pond’s drain pipe travels across the settling chamber and up into it. Therefore, the settling chamber should be visible and concealed behind plants, rocks, or enclosures.

Step Seven: Install The Water Pump

Purchase a pump that can pump half or more of your pond’s water volume per hour (GPH). The water will recirculate every few hours as a result of this. It’s best if the pump is immersed. Water is pumped to the settling chamber by the unit.

Step Eight: Time To Fill Up With Water

Fill the pond with water using the garden hose. Keep a watch on the pond to prevent it from overflowing.

Step Nine: Apply The Mechanical Surface And Skimmers

Surface skimmers, which are powered by electricity, mechanically remove tiny bits of detritus from the water. Some skimmers float on the water’s surface, while others are placed off to the side.

Step Ten: Install The Biological Filtration

Biological filtration methods bring the aquatic system back into equilibrium by breaking down or inhibiting undesired biological development. Roots in submersible tubs, lily pads, water lettuce, waterweed, snails, frogs, birds, and other plants and animals are among the biological filtering solutions available.

After that, you may finally introduce your koi to your pond. To begin, place the koi in pond water-filled bags. Allow for a 15-minute acclimatization period. Then, allow the fish to swim out of the bags into the pond water.

Only a few fish, no more than five or six in the 5- to 6-inch range, should be added to the pond at a time. Your biological filters will adjust to the koi due to this. Keep a watchful eye on the koi for parasites or other biological issues in the first week or two.

Annual Cleaning Guide For Koi Ponds

The spring season is a time of revitalization, and your koi pond environment is no exception. With all of the winter debris gone, the pond looks more sociable, and a clean pond offers a fresh habitat for the bacteria in the biological filter and fresh water for the fish.

The quantity of pond cleaning required is determined by the size and location of the pond. In light of that, here’s what to do when it’s time to do some annual cleaning.

The Pond Must Be Drained

You won’t need to remove all of the water from your pond if you have a biological filter, and you won’t need to remove the fish. However, if you must entirely drain the pond, you must place the fish in large containers to accommodate them. Fill the containers with enough pond water to cover the fish and put them in a shady area.

If the containers are overfilled, the fish may spill out. While you clean the pond, a little aerator placed in the fish container supplies oxygen to the fish. Once the fish have been captured, drain most of the water from the pond. If there isn’t a drain on the pond, a submersible sump pump can swiftly drain the water.

You Should Remove The Plants

To make access to the pond’s walls easier, place the potted water plants outside the pond. Place the pots in the temporary fish container to keep the roots moist. If you need to separate the plants before reintroducing them to your clean pond, you can do it now.

If a plant has expanded its pot and grows through the liner, it can be repotted or left on the liner. However, leaving the roots intact makes cleaning the liner more difficult.

Walls Need To Be Cleaned

You can clean the pond’s walls with a power washer or a garden hose with a spray nozzle attachment. It’s also an excellent idea to clean any waterfalls, streams, or other water features that pour into the pond.

Pull out and dispose of any algae that have grown in the pond. Once the walls are clear, vacuum the dirt and debris off the pond’s bottom with a wet-dry vacuum. If one person vacuums at the bottom of the pool while another empties the vacuum as soon as it fills, the task will go much faster.

It would be best if you Cleaned Pumps And Filters

It’s a good idea to replace any filters on your pond’s pump in the spring. If you have a recyclable filter, you may need to use a garden hose to clean it. Follow the manufacturer’s instructions for other filters.

Each pump has its unique set of maintenance needs, so consult your owner’s handbook for details on what you should do. The skimmer basket may have gathered junk; open it and clean it out.

Time To Refill The Pond

Add new water and a chlorinator to the pond once it has been cleaned. Remove part of the water in the fish holding tank and replace it with fresh. Rep the process as needed to assist the fish in acclimating to the new water temperature and chlorine level.

The fish can return to the pond once the pond water is ready. Report any plants that require it and place them back in the pond.


Installing a drain requires some extra effort during the building process, and I would never go so far as to declare that they are vital for every pond’s success. However, as mentioned before, there are some significant advantages to getting a bottom drainer for your koi pond.

Recent Posts

Verified by MonsterInsights