Skip to main content

Koi Pond Filter

These filtration systems are suitable for Koi ponds

Koi are fascinating. They are often beautifully coloured and can be distinguished individually. Thus, they enhance your garden pond noticeably and can even represent a value investment as they grow in size. To keep them successfully, however, you have to ensure a particularly high water quality. A Koi pond filter helps you to do this. With it, you can remove all waste and create clear and oxygen-rich water.

Koi Pond Filter

Which pond filter is suitable for koi ponds is presented below. You will also learn what you should bear in mind in this context. We hope that this guide will help you to make your decision.

Koi Pond Filter – 3 recommendable models

Oase BioSmart Set 14000

Filtration System Set

The Oase company stands for very high quality, which is why it has an excellent reputation worldwide. The Oase BioSmart 14000 is a high-quality Koi pond filter. According to the manufacturer, it is suitable for a water volume of up to 7,000 litres. Conveniently, the matching pump is included in the scope of delivery, which pumps 3400 litres/hour. All individual parts are perfectly matched, so you don’t have to worry about compatibility.

The pump can be used flexibly at depths of up to 2.8 metres. Thanks to the 10-metre long power cable, there is no need for a power socket in the immediate vicinity, which contributes to a high level of convenience. However, since the connecting hose is only 3 metres long, the filter unit must be set up nearby. This requires approx. 56 cm of space on the longest side. Because it can be buried 1/3 of the way in, it is hardly noticeable in the surroundings and is also absolutely immune to storms.

Various filter media are used, which promise effective results. The sponge material can, for example, trap ammonia, nitrate, nitrite and ammonium, which are toxic to fish. In addition, there is a UV-C clarifier which can destroy small suspended particles. In addition, the water is enriched with oxygen through a special guide, which is very advantageous, especially in summer.

In summary, the Oase BioSmart 14000 is a recommendable Koi pond filter. The set also includes the matching pump as well as cable and hose. This means you can quickly put the device into operation. The degree of contamination and temperature display provide a quick overview of the important key figures. The combination of UV clarifier and classic filter elements ensures great results. Oase also gives a “clear water guarantee” for koi ponds with a filling volume of up to 3500 litres.

SunSun CBF-350C


SunSun is a private brand of the WilTec company. This is a family-run company from North Rhine-Westphalia. The SunSun CBF-350C is an extremely powerful Koi pond filter. It is also suitable for densely populated waters with a volume of up to 20,000 litres.

The scope of delivery also includes a UV-C clarifier through which 6000 litres/hour can flow, which is why you can also use a very powerful pump. With a power consumption of 72 watts, the unit is certainly not exactly energy-saving, but it destroys floating algae and other floating particles all the more reliably for it.

Furthermore, a 5-metre suction hose is included, with the help of which you can reliably transport even very coarse particles to the filter system. The filter is divided into 3 chambers and requires a footprint of 1.3 x 0.54 metres. It works with sponge filters, which can be easily washed out. Due to its large volume, it can also be combined with an extremely powerful pump.

All in all, the SunSun CBF-350C is a powerful Koi pond filter. These can have a volume of up to 20,000 litres. The device is robust and durable. Therefore, you definitely need a certain amount of space. If this is given, you can enjoy great results. However, a pump must still be purchased separately. Customers are sometimes very convinced of this filter.

Pontec PondoPress 15000

Koi Pump and Filter

The German company Pontec is an expert in the field of pond pumps and filters. Depending on the model, warranty periods of between 2 and 15 years are granted. The Pontec PondoPress 15000 is an inexpensive Koi pond filter. For it to work reliably, it should hold a maximum of 7500 litres of water.

Conveniently, all components are included in the scope of delivery so that the system can be put into operation directly. They fit together perfectly so that commissioning is uncomplicated. The pump transports particles up to a diameter of 4 mm and a total of 2500 litres/hour. The water is brought to the pressure filter via a 5-metre cable.

Inside the filter container are various bio-filter media, which separate the waste from the water in an environmentally friendly way. Beforehand, the water is also irradiated by a UV clarifier. During this process, suspended algae and particles are killed. Because it is a pressure filter, the water can also be led up to a height of 1 metre, so that you can also use this system for streams or waterfalls at the same time.

Overall, the Pontec PondoPress 15000 is a solid filter system for koi ponds up to 7,500 litres. The set is complete so that you can use the system directly. It doesn’t transport quite as coarse particles, but still works reliably overall. You can bury the pressure filter almost completely and thus hide it optimally. It only takes up about 34 cm of space in diameter, which makes it much easier to handle. The clean water can also flow out as a stream, which increases the oxygen content in the water. In addition, movements ensure that algae growth is reduced.

Koi Pond Filter – What to look for when choosing a filter

Pond size and fish population

Even very good pond filters cannot be recommended across the board to every pond owner. You should always weigh up the system against its purpose and the size of your pond. The larger your pond, the more powerful and robust the filter system must be.

To keep koi ponds clean, you tend to need a particularly powerful system. The fish produce an excessive amount of waste through droppings and constantly withdraw oxygen from the water, which also promotes faster siltation. In addition, food remains can negatively enrich the sediment. If the manufacturer recommends the system for 30,000 litres, it is therefore by no means exaggerated to use it in a 15,000 litre pond.

It is anyway the case that more power is needed for filtering, for example, than for water features and visual enhancements. Only for creating a powerful stream louse does the associated pump perhaps need to be even better.

As a rule, manufacturers base their recommended water volume on empty water. Therefore, you should apply at least a factor of 1.5 or 2. However, reputable suppliers now also provide information for fish ponds.

Pump delivery rate

The flow rate is a decisive criterion. It provides information on how much water is circulated within a certain period of time. For this reason, the information is given in either m³/hour or litres/hour.

A high flow rate tends to provide better cleaning results. The water is circulated more often and thus passed through the filter more regularly. For example, if your pond holds 24,000 litres, the entire water is circulated twice a day at a flow rate of 2,000 litres per hour. If, on the other hand, it is 12,000 litres per hour, the pond is circulated 16 times a day.

Nevertheless, you cannot rely on gigantic flow rates across the board. They must also be suitable for the filter. If the filter is overloaded with the amount of water, it will simply be pushed through together with the debris and end up back in the water. Due to turbulence, the result can be even worse than working completely without a filter. You should listen to the manufacturer’s recommendations and only exceed them moderately. In any case, you should know what you are doing.

Head of the pump

You should also pay attention to the delivery height. While it doesn’t matter for water features, a pump for filtering should be placed at the lowest possible point in the pond. There, of course, it has to use a lot of energy to move the water up the hose. If this is not successful, the purchase was completely wasted.

Common filter pumps manage a delivery height of between 2 and 3 metres. It is definitely worth considering a small buffer in this context. If you have a very steeply sloping pond, you may have to be able to guarantee much better delivery heights.

Furthermore, you have to make sure that the connections fit together. Common diameters are between 25 and 50 mm. With the help of a grommet, the diameter can be adjusted to some extent. Of course, the hose and the mains cable must be long enough to allow a flexible choice of location.

Filter medium

To achieve the best possible results, many manufacturers use multi-chamber systems. Different filter media are used here. Sponges, Japanese mats and bio-filter balls are frequently used. Often, the water is first cleaned of coarse debris. Then it becomes more specific.

Depending on the porosity, sponges can remove toxic substances such as ammonia, nitrate and nitrite from the water. Japanese mats and filter balls can also encourage bacteria and pathogens to settle on them.

A separate UV-C clarifier is also useful. This works with UV rays, which can remove even the smallest suspended particles. The UV light changes the protein structure of floating algae and co., whereupon they die.

Sometimes the water is then specially aerated and enriched with oxygen. This is certainly a very useful function in a Koi pond filter.

In a standard flow-through filter, the cleaned water leaves the filter system via a PVC pipe about 50 mm thick. If this is positioned at a certain height, additional oxygen is created here. In addition, movements in the water reduce the growth of certain substances.

Maintenance costs

One must be aware that every pond filter requires a certain amount of maintenance. The filter media become dirtier and dirtier over time and at some point can no longer provide filter performance. In this case, you should switch off the pump and remove the filter elements. They should be rinsed out 1-2 times per season with the garden hose and then wrung out several times.

The larger your filter system is, the less often you will have to clean it. When cleaning, you should avoid using hot water and washing-up liquid. At some point, however, it will be necessary to dispose of the entire filter media and replace it with new ones.

Another expense is incurred before winter. The filter system is usually not frost-resistant and should therefore be dismantled in good time. The situation is different with the pump. If it has been placed deep enough, without the potential for freezing, it can remain in the water over the winter.

Power consumption

Power consumption is not an insignificant factor either. It is expressed in watts and is also referred to as power consumption in professional circles. If you want to circulate a koi pond reliably, you tend to need a high power consumption.

High-quality devices can be recognised by an optimal ratio between power consumption (as low as possible) and flow rate (as high as possible). Basically, however, the power consumption is already an indication of the potential. You should therefore not deliberately aim for minimum energy costs. If you do, the system may not work properly and not build up enough pressure.

There is the possibility of using solar pumps. These do not produce any running electricity costs because they draw their energy from the sun. However, they are too weak for filtering koi ponds.


Of course, the price also influences the choice. A Koi pond filter is rather expensive. If your own fish are important to you and you also expect a high water quality in summer, you should plan on at least 200 Pounds.

To look after large koi ponds and particularly expensive Japanese koi, on the other hand, you should be prepared to invest a four-figure sum. For this you get very efficient and durable filter systems.

Koi pond filter – Requirements are particularly high

Koi fish are sensitive. They have high expectations of the water quality, but deteriorate it themselves quite vehemently through excretions. Accordingly, you need a very efficient and high-quality filter system. If the fish die, a four-digit loss can quickly occur. Japanese koi in particular need to be properly cared for. A Koi pond filter should therefore have the following features:

  • High flow rate and filter capacity (even in small ponds it should be at least 2000 litres/hour).
  • Remove potentially toxic substances such as ammonia, nitrate and nitrite.
  • Encourage bacteria to settle in the filter material
  • Destroy fine suspended algae (UV clarifier advisable)
  • Large particles, from 8 mm, should also be able to be absorbed by the hose and the filter system.
  • Should produce additional oxygen through certain water flow and drainage (especially important in summer)
  • Vigorous circulation of the water, so that oxygen gets into all layers
  • Chemical cleaners should not be necessary

Video of a Koi Pond DIY Filtration System

Related Posts