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Best Koi Pond Filter System For Excellent Water Quality & Healthy Fish | Product Reviews

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Keeping your Koi healthy means you’re going to need to maintain their water. The type and size pond filter you use can make or break your maintenance schedule. If you choose the wrong one, you could spend most of your time maintaining the pond instead of enjoying it.

However, with one of the best koi pond filter systems, you can enjoy crisp, clear water, knowing that your fish are healthy and vibrant. Buying the right filtration system for Koi ponds can be difficult to do, though.

That’s why we’ve put together this guide for you. In it, you’re going to see some of the best, highest-rated Koi pond filters as well as useful tips on how to make the right choice for your specific Koi pond setup.

What’s The Best Koi Pond Filtration System?

To help you save time, money, and avoid the frustration of buying the wrong equipment, we have outlined some of the best pond filtration systems for Koi ponds below.
crystal clear water - helps maintain clean and healthy pond water
  • Long Lasting And Easy To Use Filter Available
  • Easy To Install And Clean
  • Great Construction And Convenient
advance features include the built-in cleaning indicator - highly recommended
  • Easy To Install And Clean
  • Crystal Clear Water
  • Easy To Maintain
strong filter - outstanding value
  • Easy To Install, Use And Clean
  • Converts Your Dirty Ponds Into Crystal Clear Water
  • Highly-Rated Filtration System
affordable - great value
  •  Provides A Clearer And Healthier Pond
  • Works Great And Easy To Install
  • Good Quality And Easy To Clean
quiet and energy efficient - eco friendly
  • Quiet Operation
  • Great Pump And Filter System
  • Keeps The Water Clear
  • Very Easy To Set-Up
creates waterfall - use with pumps 500 to 4500 GPH
  • Uses A Standard Filter Size
  • Easy To Use And Install
  • Energy-Efficient Design
Clean water - great equipment for a small pond
  • Easy Installation With Different Fountain Options
  • Adjustable Fountain
  • 3 Year Limited Warranty
keeps pond clean - prevents pump from clogging
  • Takes Less Time And Effort To Maintain
  • easy to install
  • sturdy


  • long lasting and easy to use filter available
  • easy to install and clean
  • great construction and convenient

TetraPond is one of the most reputable, well-known brands in the pond keeping and aquarium keeping industries. The Bio-Active system can provide both mechanical and biological filtration and works to kill bacteria by exposing them to ultraviolet light.

Pros & Cons 


  • The Bio-Active filter allows ample amounts of water to pass through.
  • The internal filter provides UV clarification.
  • TetraPond is one of the most well-known brands today.


  • Backwashing the system can be challenging to do.
  • You’ll need to backwash the filter each week.

Did You Know?

If your water quality consistently fluctuates, adding carbon charcoal to the system can help keep your water’s quality from swinging.

2. OASE Biosmart 5000 Pond FilterAdvance features include the built-in cleaning indicator


  • easy to install and clean
  • crystal clear water
  • easy to maintain

OASE is another great manufacturer that is well-known and well-received in the outdoor garden and pond keeping industries. The Biosmart 5000 pond filter is perfect for people who have smaller numbers of fish. The filtration system uses gravity to feed the biological and mechanical filters and contains an internal self-cleaning mechanism to reduce your maintenance schedule.

Pros & Cons 


  • The filter can flow up to 5,000 gallons of water.
  • A built-in temperature gauge lets you monitor your water’s temp.
  • The filter will alert you when it needs to be cleaned.


  • You may need to replace the outflow valve.

Did You Know?

A quality pre-filter can help your pressurized system operate even more efficiently.


  • easy to install, use and clean
  • converts your dirty ponds into crystal clear water
  • highly-rated filtration system

The Best Choice Products 4000L Pressurized Bio Filter is built to move 4,000 liters of water (or 2,500 gallons) and is made to work in ponds that have standard numbers of fish. The system uses an internal UV light clarifier to help promote healthy bacteria and combat harmful bacteria while including the hardware you need to get it up and running as quickly as possible.

Pros & Cons 


  • The system includes both biological filtration and UV clarification.
  • The pump flows up to 2,500 gallons of water.
  • This is a highly-rated filtration system.


  • Sludge may form at the backwash outlet.

Did You Know?

Pressurized systems are more expensive upfront but can reduce your maintenance costs as time goes on.


  •  provides a Clearer and Healthier Pond
  • Works great and easy to install
  • good quality and easy to clean

The Jebao CF-10 Pressurized Pond Bio Filter w/ Clarifier is a pressurized system that is capable of moving up to 1,500 gallons in planted ponds and 1,000 gallons in fish ponds. For heavily stocked ponds, the filter is capable of handling up to 500 gallons. The internal UV lamp helps combat harmful bacteria.

Pros & Cons 


  • The filter includes both biological filtration and UV clarification.
  • The pump is capable of moving up to 2,500 gallons of water.
  • The built-in indicator lets you know when it’s time to clean the filter.


  • Sludge has been known to build up near the backwash outlet.

Did You Know?

The quickest way to determine the size pump you need to use is to determine how many gallons of water are in your pond and purchase a pump that flows the same amount per hour.

5. POND BOSS Filter Kit w/ Pumpquiet and energy efficient


  • quiet operation
  • great pump and filter system
  • keeps the water clear
  • very easy to set-up

The POND BOSS Filter Kit w/ Pump is known for being economical and energy-efficient. It is a submersible system that combines your biological and mechanical filtration that is good for up to 500 gallons of water. The lid design keeps debris from causing the system to back up, and the kit includes a pump for your fountain with a nozzle head.

Pros & Cons 


  • The filtration system filters biological and UV clarification.
  • The pump can flow up to 2,500 gallons of water.
  • The filter alerts you when it needs to be cleaned.


  • Backwashing the pump can be a dirty job.

Did You Know?

Maintaining your water’s quality is easier to do when you spend time understanding your filtration system.

6. TetraPond 26595 Waterfall Filtercreates waterfall


  • uses a standard filter size
  • easy to use and install
  • energy-efficient design

The TetraPond 26595 Waterfall Filter is explicitly built for waterfalls and attaches to your pump to create a beautiful 12” waterfall. The filter is designed to work with ponds as large as 1,000 gallons. You can use both lava rock and activated charcoal inside of the filter to cultivate helpful bacteria and give them a place to grow.

Pros & Cons 


  • This kit includes both mechanical and biological filtration.
  • The design works to capture both large and small particles.
  • This is an energy-efficient design that’s easy on your electric bill.


  • The kit may float around your pump if you don’t anchor it down.

Did You Know?

Stack your mechanical filtration media from coarse to medium-density, to fine-density so your system can efficiently remove debris.


  • Easy installation with different fountain options
  • adjustable fountain
  • 3 year limited warranty

The TetraPond Filtration Fountain is another kit that works with a submersible pump and uses dual-layer pads to filter out larger debris. The fountainhead assembly comes with three different heads to create a unique pattern in your pond. You also get a diverter valve and an adjustment knob to help control the amount of water flowing through the fountain.

Pros & Cons 


  • The kit includes everything you need for a small fountain in your pond.
  • You get a variety of three different fountain heads.
  • This fountain kit lets you create smaller container ponds.


  • The floating filter box will need to be anchored to the bottom.
  • Some customers complained their pump didn’t operate.

Did You Know?

If your pond is located near trees or shrubs that create large amounts of debris, you might consider installing a pond net to keep the debris out of the water.


  • takes less time and effort to maintain
  • easy to install
  • sturdy

Another great filtration system from TetraPond is the submersible Flat Box Filter that is designed specifically with Koi ponds in mind. It is designed to work with up to 500 gallons of water.

Customers have reported that the box contains space for you to install activated carbon charcoal filters to increase the amount of filtration you are getting.

Pros & Cons 


  • The kit includes all the fittings you need to get started.
  • The system flows up to 2,000 gallons of water.
  • You can install biological filtration into the system.


  • The system does not include biological filtration.
  • Disconnecting the tubing can be difficult to do.

Did You Know?

Maintaining crystal clear water and keeping your fish healthy is easy to do when you install an adequately-sized filtration system.

Koi Pond Filtration System Buyer’s Guide

When you are looking at different filters, there are three primary considerations you will need to make to ensure you are getting the best for your setup.

  1. The size of your pond, in gallons of water, and how many water features or fountains you have in the pond.

  2. The number of fish that you’re keeping in the pond.

  3. The type of filtration that works best for your pond type and water features.

The number of fish and the size of your pond are going to be the most significant factors to consider.

The filtration system you choose significantly depends on whether you intend to hide it within your pond or if you’re going to keep it outside of the pond. You will also want to consider whether you prefer water passing through the filter before it reaches the pump, or after.

If you have water features, such as a waterfall or fountain, you will need to purchase a pump and filter system that is capable of moving enough water to keep your features flowing.

The first step is choosing the proper size.

What Size Filter System Do I Need For My Koi Pond?

This equation starts by figuring out how many gallons of water are in your pond. If you have a rectangular or square pond, the equation is relatively simple. Multiply the length by the width by the depth and then multiply that number by 7.5.

That will tell you (approximately) how many gallons of water you have.

For ponds that are round or circular, you’re going to need to use a different formula. You can multiply the radius by the radius and then by the depth. Multiply that figure by 3.14 and then 7.5.

The equation will tell you how many gallons of water are in your round pond.

If your pond doesn’t have any water features and you’re not keeping fish, but you have different levels of depth, you’re going to need to break the formula into sections, taking into account each different depth.

It does get a bit more complicated when you have an irregular shaped pond. You’ll want to break the formula down into sections and add the measurements together to determine how many gallons of water are inside the pond.

Your main goal is to purchase a pump that flows the same amount of gallons per hour that your pond contains. If your pond holds 500 gallons of water, a pump that is capable of flowing 500 gallons of water per hour is going to be required.

What If Your Pond Has Water Features?

Water features are going to require you to add to the equations you just figured out. If you have waterfalls or fountains, you will need to take the amount of tubing or pipes into consideration.

You also want to determine how much plumbing you have as well as the height of the waterfall, fountain, or water feature. This information is needed to determine how much flow your water features are going to require.

The amount of pressure that your fountain or water feature requires will come down to being provided by your pump. This is called the “head height” of your water feature.

The amount of water that is contained inside of your water feature will need to be added to your pump’s total gallon-per-hour rating to ensure you have enough power available.

What If Your Pond Contains Fish?

Your filtration system will need to take into account the extra load on the system. You will want to ensure that your pump can flow enough water to keep pressure moving through the added layers of filtration.

For Koi ponds, you are typically going to have three types of filters: mechanical, biological, and chemical. Each type of filter will put additional strain on your pump.

While the formulas above are usually enough for your Koi pond to stay healthy and vibrant, if you have more than the average number of fish, you will want a pump that is capable of flowing a higher amount of water.

As you add more filtration into the system, the pump will work harder to keep water flowing through it. A pump that has flow rate adjustability can be a lifesaver for dialing in the exact amount of flow you need.

Types Of Filtration For Koi Ponds

If there’s one thing you’re going to learn about your Koi fish is that they can be incredibly dirty fish. That means you’re going to need to layer your filtration system if you want to keep your water clean.

With the right type of filtration, your pump will work to keep your water clean and ensure you never realize how dirty the fish can be. With the wrong system, though, you’re going to be continuously dealing with water quality issues, algae blooms, and harmful bacteria that make your fish sick and stressed out.
  1. Biological filtration

  2. Biological filtration refers to using helpful bacteria to break down the harmful bacteria inside of your pond. Useful bacteria can grow when you provide them with a large surface area.

    You will want to look for a filtration system that comes optimized with biological filter media and provides excellent water flow through the rest of your system. As the media begins doing its job, you will have fewer issues with algae blooms and harmful bacteria.

  3. mechanical filtration

  4. Mechanical filtration refers to your system’s ability to remove large debris, such as fish waste, leaves, twigs, and other objects that make their way into your pond. Most mechanical filtration is layered foam or sponges of different coarseness and thickness.

    The multi-step process starts by layering coarse media over medium-density medium and then backing it with a layer of fine-density media. This lets you capture large objects first, then medium-sized objects, and then the fine-density media usually acts as your biological filtration.

    This process of layering helps ensure your pump can maintain proper flow while knocking out the waste in your water.

  5. Chemical filtration

  6. Chemical filtration is the third type of filtration that your system will require. You can use products such as water treatments and clarifiers to keep the chemicals in your water to a minimum.

    Products, such as activated charcoal carbon filters, can help remove chemicals such as chlorine, ammonia, nitrites, and nitrates. These chemicals can cause your fish to become sick if you leave them unchecked.

  7. water quality and clarity

  8. When you have a quality filtration system in place, your water’s quality and clarity will be easy to maintain. The best way to maintain your water, though, is to maintain your filtration system.

    The system that you put together should be easy to maintain and clean, while also ensuring that you are getting adequate water flow. If the system is hard to clean and maintain, you are going to be less likely to maintain it -- and your fish & pond will suffer.

Two Types Of Koi Pond Filters

There are two main types of pond filters and pumps you’re going to encounter. The type you choose depends mainly on your setup.

The first is pressurized koi pond filters, and the second is non-pressurized koi pond filters.
  1. Pressurized koi pond filters

  2. Pressurized pond filters, or bead filters, are going to be the most popular option for many people. With pressurized pumps, you can install them below your pond’s water level while still maintaining proper pressure.

    This gives you quite a few different installation options while keeping your filtration system out of sight. Pressurized systems do provide slower water movement, which can be a downside to some people, but this also comes with advantages.

    When your water moves slower, the filtration media inside of the system has more time to remove waste, debris, and harmful bacteria. However, slower-moving water also means that your biological filtration media may have to work harder to remove harmful bacteria.

    Helpful bacteria need large amounts of water flowing over them to process out the harmful bacteria in your water. 

    If you have large numbers of fish, you are going to notice the slower moving water causing problems. However, for smaller amounts of fish, you likely won’t see the difference in a pressurized system.

    To maintain your water quality, you will likely need to add extra steps to help your filtration system function at its peak. The additional steps could include activated carbon charcoal and supplementing healthy bacteria.

  3. non-Pressurized koi pond filters

  4. Non-pressurized koi pond filters, while not nearly as common as pressurized systems, are still a viable option for some people. They offer excellent mechanical and biological filtration without causing your water pressure to drop.

    However, non-pressurized systems offer fewer installation options. You do not have the same issues that pressurized filters provide, but non-pressurized systems give your helpful bacteria more room to thrive.

    If you want to obtain the best of both types, you can use a non-pressurized filter as a pre-filter in your pressurized system. This will give you increased biological filtration while also ensuring your mechanical filtration has enough flow to function properly.

Do You Need A Pre-Filter In Your System?

In many cases, you’re going to benefit significantly from filtering the water before it enters into your pressurized filtration system.

When you have large numbers of fish in your pond, a pre-filter can dramatically reduce your maintenance schedule. Pre-filtering functions by putting a secondary filter in the front of your larger system.

This secondary filter collects debris and gives your helpful bacteria a chance to begin cleaning the water with ample amounts of water flowing over them. Most pre-filters are nothing more than a skimmer box or leaf basket.

Determining whether or not you need one comes down to the type of pond you’re keeping and how much debris you are dealing with. You will also want to consider the type of pump you are using and how well it can flow water through the system.

Use Activated Carbon Charcoal

If you want to achieve optimal efficiency in your filtration system, you can add activated carbon charcoal along with a pre-filter. Activated carbon acts as a chemical filter and lets the helpful bacteria inside your system work even harder.

When you are monitoring the water in your pond, if you notice ammonia, nitrites, and nitrates rising, adding carbon charcoal can help reduce the numbers. This should be your first line of defense for most people.

Swapping out the charcoal every few months is significantly easier than battling the quality in your water weekly. Many people underestimate how powerful simply adding charcoal to their system can be, but the result proves itself time and time again.

While adding activated carbon charcoal and a pre-filter system can be a more significant investment upfront, having these included in your system can save you significant amounts of money as you own the pond for months and years.

What’s The Best Filtration For Koi Ponds?

After extensive research, comparing dozens of different filter systems, and reading through other customer reviews, we have found that the best Koi pond filter system in 2019 is the TetraPond Bio-Active. It provides both mechanical and biological filtration and makes it easy for you to add activated charcoal for chemical filtration.

Affiliate links & Images from Amazon Product Advertising API. Last update on 2022-09-11.

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