The Best Choice Products 4000L Pressure Bio Filter is the best koi pond filter you can buy for the value it provides.

Your koi pond is a thing of beauty.

You take great care of the fishes and are proud of it.

But looks like your pond is starting to collect muck and getting dirty. That’s not a good thing for the fishes.

It’s time for you to get a good koi pond filter to resolve this problem. So let’s take a look at the best koi pond filter you can purchase.

Product Rating Price
Best Choice Products 4000L Pressure Bio Filter 1
TotalPond Universal Pump Filter Box 2
Pond Boss Filter Kit with Pump 3
CNZ All-in One Pond Filter System 4
XtremepowerUS VD-21559EP 10000 Koi Pond Pressure Bio Filter 5

What is a koi pond filter?

When you have a pond, there’s a pond filtration system that you need. This consists of the pond pump, pond aerator, and a pond filter.

The filter is a small box that is attached to the pond pump. The water flows from the pump through the filter that cleans it up before pushing it to the pond.

What are the different types of koi pond filters?

The main types of filter you can get is based on whether you submerge it in water or not.

The best thing you can do is pick a filter suitable for your pond pump. So if your pump is submersible, your filter should be as well. But if your pond pump is inline then your pond filter should be as well.

Do you need a koi pond filter?

If you’ve a small pond with just a few small fishes, you could use plants to perform the filtration. Then you don’t need a pond filter.

But if you have a lot of koi fishes and need to feed them often, it’s best to use a pond pump and filter to keep it clean.

The pond filtration system also helps keep the pond clean from algae and dirt that collects over time.

How to choose the best koi pond filter

It’s important to pick the pond filter that works best for your pond. Let’s take a look at some factors that can help you with this.


The size of your pond is important to consider when buying the filter. If the filter is too small it’ll not work in cleaning your pond well. If it’s too large, you’re wasting your money.

Also consider the size of the pump. Because if the filter is too large for the pump, it’ll work harder and burn out. And if the filter is small for the pump, the filter won’t be able to cope up and fail to keep the pond clean.

You can figure out the size of the pond by measuring the length, width, and depth of your pond.

Amount of fishes

Another important factor for your koi pond filter is the fishes in your pond. This should include the number as well as size of the fishes.

You would ideally want to stay at or below five inches of fish per gallon of water in the pond.

Do remember that koi fish produce a lot of waste. Maybe 2-4 times that goldfish would produce. This means your pond filter should have double the capacity to filter the water.

UV clarifier

Some pond filter come with a UV clarifier that helps clean the water. If you can get a model with one, it’s good for an extra level of purification.

UV light has been well-proven to have some very positive effects on water and air. The science behind this is not yet fully understood, but it seems to work. Here is a patent for a dental apparatus that uses UV light to purify air and water for sterile use.

Ease of access

Your koi pond filter is going to get dirty over a period of time and you’ll need to clean it up.

There are filters that come with self-cleaning but even those require some cleaning after a while. Make sure it’s easy to access the filter canister so you can clean it without damaging the casing or the filter.

Indicator light

Some filters come with an indicator light to show when it’s time to change the filter. This is a useful feature as it’s convenient and time-saving.


Make sure the koi pond filter you pick is compatible with your pond pump. If you don’t have any filtration setup then this is not a concern as you can pick compatible components.

But if you already have a pond pump, make sure to pick a pond filter that is the right size and fit.

Precautions when using a koi pond filter

The main concern with a koi pond filter is that it’s an electrical system being used near water. If the pond pump and filter are submersible, you may be a bit worried.

But there’s no problem because these are usually powered by a small battery which does not create an electrical hazard.

If you’re still unsure, you can choose an inline pump and filter that are placed on the surface rather than in the pond.

The pond pump and filter you need depends on the number of fish in the pond. This number could multiply pretty fast, so you need to be aware. This means that you will end changing the filter more often than normal. To remedy this problem, just choose a pond filter with a higher capacity than required.

How to use a koi pond filter

The main thing to understand with a pond filter is the value for the intake and the output.

Unfiltered water goes into one value and comes out clean from the other. You just need to set up the right hose connections and you’re good to go.

Pro Tip: If your hose is just a tiny bit too big, you can get a hose clamp and tighten it down to seal the leak.

If you’re pond filter comes with a light indicator, make sure to install the battery so it’s turned on. You need to install the filter cartridge into the housing if it’s not already placed there.

If the filter comes in a plastic casing, you should take it out before you fit it inside the housing. Always check the instruction manual that comes with the filter to know how to install it.

Maintaining your koi pond filter

Your pond filter will be clogged with dirt and debris after a while. So it’s important to clean it up and get good use from it.

How often you need to clean it up depends on the size of the pond, the filter, amount of fishes in your pond, and the quality of the filter. The same applies for the case when you need to get your filter replaced.

In addition, you will need to occasionally change the battery for your indicator light if your unit includes such. The main indicator light will tell you when the battery needs to be changed. In some models, the device will alert you when the battery is low and needs changing.

Every once in a while, you should take your filter apart and give it a good deep cleaning. This doesn’t need to be done very often, two or three times a year would probably be enough. Over time, various deposits will build up in the device.

These filthy “leftovers” can eventually clog up the works and make the whole thing die if they build up to a sufficient level. You can greatly extend the life of your device by keeping it as clean as possible.


No products found.

The Best Choice Pressure Bio Filter can be used with ponds up to 4000 gallons of water. It can filter 2500 gallons of water with a normal fish load and 1500 gallons with a heavy fish load.

The UV clarifier is a useful feature that helps clean algae from your pond and prevent them from growing.

The Best Choice Products Boi Filter is easy to clean due to the backflush feature. This can be a little tricky to use though. This filter also comes with a flow indicator so you know when it’s time to clean the filter.

The Best Choice Pressure Bio Filter does not need to be cleaned as often.

Pros Cons
  • Handles up to 4000 gallons
  • UV clarifier
  • Backflush feature
  • Flow indicator
  • Does not need to be cleaned often
  • The backflush feature can be hard to use

No products found.

The TotalPond Universal Pump Filter can be used for small ponds that contain up to 500 gallons of water.

It can clean the water, promote growth of beneficial bacteria, and protect the pond from debris.

This is a kit that will work with nearly any pump, and to make it easier to use, there is a 16-foot power cord that many people will find useful. This long cord will allow you to keep the power going, no matter how much space you need to reach an outlet.

This filter is also designed to help keep the scum off of the top of the water, and even though it is not the easiest option when it comes to keeping koi ponds clean, there are ample features that you can use to keep it in good order.

The only drawback is that this filter is lightweight so it floats in the pond. You need to use rocks or heavy material to keep it from moving.

Pros Cons
  • Useful for small ponds up to 500 gallons
  • Promotes growth of beneficial bacteria
  • 16-foot power cord
  • Removes scum from top of the water
  • Comes with multiple bio balls
  • Lightweight so needs rocks to hold it in place

Pond Boss Filter Kit with Pump
  • Ecofriendly Filter kit
  • Energy efficient
  • Quiet operation

Last update on 2024-03-04 // Source: Amazon Affiliates

The Pond Boss Filter is eco-friendly and energy efficient. It has a quiet operation so you don’t need to worry about it creating noise.

It has a filter, pump, and nozzle. This makes it inexpensive compared to buying each of these components separately.

It comes with a UV filtration system that helps prevent algae from growing in the pond.

The fountain head that comes with this system sprays water out of the pond.

Pros Cons
  • Eco-friendly
  • Energy efficient
  • Quiet operation
  • Filter, pump, and nozzle included
  • UV filtration system
  • Fountain head sprays water out of the pond

CNZ All-in One Pond Filter System
  • Reduce algae, Clean Pond water
  • 3 Fountain Water Feature Attachments
  • Adjustment valve for regulating flow to fountain head and/or auxiliary water feature.

Last update on 2024-03-05 // Source: Amazon Affiliates

The CNZ pond filter system has a 13-watt UV sterilizer that can prevent algae from growing in your pond.

The adjustment valve can be used to control the flow of water to the fountainhead.

It has a large coarse filter foam that filters debris and bacteria from the water with the three biofilter media baskets.

This is a submersible filter which means it won’t be visible near the pond.

It’s easy to clean the filter because it’s easy to access the filter media areas by removing the clips on the opposite sides of the filter. The filter is thick so this does take a little bit of time for cleaning.

There are three fountain attachments that can be used for different displays in the pond.

Pros Cons
  • 13-watt UV sterilizer
  • Adjustment valve to regulate water flow
  • Large coarse filter
  • Three fountain attachments
  • Easy to access filter media
  • Takes time to clean due to thick filter

No products found.

The XtremepowerUS pond filter has a 13-watt UV clarifier that helps keep algae away from your pond.

It’s an external filter that is not submersible. But it can be half-buried in the ground so it’s easy to hide.

It can handle ponds that hold up to 4000 gallons of water.

This pond filter is easy to set up and has a cleaning indicator light so you know when it’s time to clean the filter.

It’s easy to take this filter apart and clean it up. It’s nice to have bio-filtration as well.

As a final note, this filter is made in such a way that it can be half-buried in the ground. This makes it easy to hide behind a bush.

Pros Cons
  • 13-watt UV sterilizer
  • Can handle up to 4000 gallons of water
  • Easy to set up
  • Cleaning indicator light
  • Doesn’t require cleaning often
  • Poor instruction manual
  • Canister is made with flimsy plastic

Our recommendation

We recommend the Best Choice Pressure Bio Filter as the best koi pond filter you can buy.

It can deal with ponds up to 2500 gallons of water with a normal fish load and 1500 gallons with a heavy fish load.

The UV clarifier is a useful touch that can keep your pond free from algae and unwanted bacteria.

You don’t need to clean it often and it’s easy to clean if you need to. You also know when it’s time to clean with it’s indicator light.

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