Last Updated on April 23, 2023 by Coral Realm

The addition of a water feature or pond of some type to a garden, whether rural or urban, has always been a popular component. The calm and tranquility offered by a body of water is beyond question, and a water feature of any type will enhance any garden, large or small. 

The creation of a garden pond is a wonderful asset. Even a tiny body of water will attract wildlife and create a focal point. In an urban setting, small ponds can provide a vital lifeline to species of frogs and newts and give untold pleasure. 

A garden pond is the perfect way to begin or expand your fish keeping hobby; whether you’re an experienced aquarist wishing to explore new, hardier fish species able to withstand outdoor conditions, or whether you are new to the hobby and introducing added interest to your pond by introducing fish. When coupled with the stocking of either a single species or a combination of fish species suitable for an outside pond, there is simply no greater pleasure.

A garden fish pond is likely to be a man-made structure – unless you are lucky enough to have a natural pond, but they can still be wonderful additions to the garden providing peace and pleasure.

There will always be a fishpond size suitable for your garden, even if you only have a very small area available. From ready made patio ponds or tubs, or your own creation dug to size and carefully lined with a pond liner, there are many ways to create your garden pond.

Having decided on the best possible location within your garden and created or purchased your garden pond, there are still many things to consider before you purchase the fish and stock your pond.

You will need to consider an appropriate selection of aquatic and marginal plants suitable for the location of your pond, any gravel and/or sand substrate for your pond, the addition of rocks and wooden structures for added interest for your fish, aeration and some form of filter system to keep your pond water clear, clean and healthy. You may like to read the following articles:

  • How much sunlight does your fish pond need?
  • Can ponds thrive in shady conditions?

A murky, dirty pond full of debris from nearby trees will not support either wildlife visitors to your pond or your own selection of pond fish should you choose to keep them.

In this article therefore, we will be focusing on pond filtration systems and giving you our considered suggestions.

There is a huge choice when it comes to researching and purchasing a filter system for your pond, and the choice can be a bit overwhelming. We will be reviewing a range of different types of filter systems, and giving you our suggestions. 

Firstly, though, an introduction to the different methods of filtration within a pond is required. Armed with this knowledge and understanding, you will be in the best position to make an informed purchase that is right for your particular pond. This will avoid you making any costly mistakes with your purchase of a filter, and will ensure the best environment for your pond fish.


Garden Pond Filter Options to Facilitate Low Maintenance 

Not all ponds will require a filtration system; some natural, wildlife ponds can manage to sustain a healthy environment without one. Even in this case, though, you will need to ensure you remove fallen debris from the pond on a regular basis. This will prevent the buildup of sludge and harmful toxins which can affect the health of the wildlife that are attracted to your pond.

However, if you are keeping fish and their health is your priority, then some form of pond filter will make a big impact on keeping the pond water clean, clear and healthy for your fish.


There are three different types of pond filtration systems available on the market, and sometimes you may need more than one type to work in combination with each other to keep your pond water clean and clear.

Fundamentally, there are three main categories of filter system : mechanical, biological and chemical, and we will examine each of these below. 

Mechanical Filtration Systems

When considering the best filter for your garden pond, mechanical filtration is often considered the first stage in a garden pond filtration system. As the name suggests, it mechanically filters and removes particles and debris suspended in the body of water. 

This is an extremely important part of filtering a garden pond, because by physically removing these particles from the water, the subsequent phases of filtration are under less pressure. The most common type of mechanical pond filter will contain some type of media designed to physically trap debris within the pond water.

Large debris particles, if allowed to reach the biological filter, or biological section of a multi-layered filter, will simply clog up the filter media resulting in a reduction in effectiveness in breaking down the harmful waste products.

Biological Filters

Biological Filters rely on the use of bacteria to keep the water clean and healthy by breaking down waste products within the pond environment, and ultimately converting them into benign and useful substances that can even be used as feed and fertilizer for your aquatic planting; namely carbon dioxide.

The media used within the filter creates a very large surface area upon which beneficial bacteria can multiply, and these helpful bacteria are responsible for breaking down toxins within the pond.

By converting waste products into carbon dioxide in this way, the biological filter is assisting in a vital process for plants – photosynthesis. 

Photosynthesis is a chemical process by which green plants convert light energy into chemical energy. Energy from light is the energy source used by green plants to photosynthesize. Photosynthesis takes place in the leaves of a plant and this process requires carbon dioxide and water, and using the energy from the sun the process produces glucose and oxygen, with this by-product of oxygen being so vital to the health of the pond and fish.

Plants are so important within a pond as they provide oxygen as a by-product of photosynthesis; naturally vital to the health of your fish. The production of carbon dioxide as a by-product of biological filtration is therefore an asset in the ecology of your garden pond. 

Chemical Filters

The idea behind chemical pond filter systems is that certain substances have the ability to bind with the pollutants found in ponds and effectively remove them from the water. Chlorine, nitrates and ammonia are just some of the pond pollutants that can be removed by a chemical filtration system.

One of the most readily used substances in a chemical filtration system is Activated Carbon. It has the capacity to remove waste products produced by your fish stock, and other pollutant substances.

Chemical filtration is generally considered to be more appropriate within the aquarium environment rather than for garden ponds. With efficient mechanical filtration and a good biological filter, the chemical filtration may not be necessary. 

UV Clarifiers

UV Clarifiers and UV Sterilizers use special high output ultra violet bulbs housed within a protective sleeve or cover, which emit ultra violet light. These filters work using the premise that algae and harmful bacteria within the pond are sensitive to ultra violet light. Exposure to UV light, even briefly, can therefore kill the algae and bacteria and prevent an unhealthy build up within the pond.

Ultraviolet clarifiers are available as standalone units, but very often are combined with biological filters.

Pond water is pumped through the path of the ultra violet light, exposing and destroying the algae, rendering the water clear.

Although advice varies, a good reckoner is to allow 10 watts of ultra violet light per 1,000 gallons of water for clarification, increasing to 30 watts of UV light for 1,000 gallons if aiming for sterilization. 

9 Best Pond Filter Reviews

9 Best Pond Filter Reviews

1) Aquascape UltraKlean Biological Pressure Filter

The Aquascape UltraKlean Biological Pressure Filter is a brilliant filter for larger ponds. There are two models available; the smaller has a capacity of 2000 gallons with a flow rate of 2700 GPH, and the larger has a capacity of 3500 gallons with a flow rate of 5200 GPH.

The Aquascape UltraKlean Biological Pressure Filter features a high output ultraviolet sterilizer and an integrated electronic bulb-saver option, which provides you with increased filtration power for optimum water conditions and crystal clear pond water.

A unique sponge free design maximizes mechanical and biological filtration while decreasing maintenance requirements. The UltraKlean BioBalls pack together in the filter, creating small channels through which the water flows and leaves behind debris.

It is very simple to clean and backwash; a simple to use feature enables it to be backwashed in under 5 minutes without getting your hands dirty!

2) TetraPond Submersible Flat Box Filter

TetraPond Submersible Flat Box Filter, For 250 To 500 Gallon Ponds
  • SUBMERSIBLE FILTER: Flat box filter prevents pump from clogging and keeps pond water clear and clean.
  • PARTS INCLUDED: Coarse and fine foam pads, tubing and three hose fittings.
  • CONVENIENT: Attach to various pump inlets – easy to detach for cleaning.
  • WARRANTY: Includes a 1-year limited warranty – see product packaging for details.
  • USAGE: Ideal for use with ponds up to 500 gallons.

Suitable for ponds up to 500 gallons, this submersible filter by Tetra Pond is ideal for the smaller pond. It fits pumps ranging from 200 to 2000 GPH so if you are using a strong pump to power a water feature it should still work fine!

The TetraPond Submersible Flat Box Filter is good for pre-filtering the water before it enters the pump. It will prevent the pump from becoming clogged with debris by trapping the detritus and only enabling clear filtered water through to the pump stage.

You will need to buy your pump separately, as this is just the pre-filter system.

3) Danner Mechanical Pond Filter

Danner Mechanical Pond Filter
  • Innovative Low Profile Filters are designed to be unobtrusive in the bottom of the pond and its large surface area means less frequent cleaning. More than one filter can be connected to a pump using a tee fitting and offer filtration.
  • The filter media is easily rinsed or changed and less time consuming than many similar filters of its kind.
  • For Use with Pumps Up To 1000 GPH
  • 12" x 12" Filter Box with Locking Handle
  • Complete with 3/4" I.D. Tubing and Fittings

Suitable for small to medium sized outdoor ponds, this Danner mechanical pond filter measures 12” by 12” and comes complete with a coarse filter pad and activated carbon filter pad. 

This filter has advantages over the type that ‘skims’ over the pond surface, insofar as it avoids the potential problem of inadvertently sucking up any smaller fish or tadpoles from any fish or newts that inhabit your pond.

By filtering the water before it goes through your pump, this filter will aid the longevity and smooth running of your pump.

This filter is easy to keep clean, by simply disconnecting from the pump and careful separating the various layers. It comes apart easily to remove the filters for cleaning. The handle on the top of the pump ensures easy removal from the pond for cleaning.  It is then a simple process to reassemble and connect back up to your pump.

We must stress, though, that this is for the smaller capacity garden pond, up to a 10 foot square pond created using a rubber pond liner

4) Pondmaster DNR02200 Extra-Capacity Mechanical Filter

Pondmaster DNR02200 Extra-Capacity Mechanical Filter
  • For Use with Pumps Up To 2000 GPH
  • 12" x 24" Filter Box with Carrying Handle
  • Polyester and Biological Foam Inserts,
  • Connects to Intake Side of Pump
  • Complete with 1" I. D. Tubing and Fittings

For ponds up to 1000 gallons with a relatively light fish population, this 12” by 24” mechanical filter represents a sound option.

This traps debris from the pond as it is drawn into the filter using carbon and polyester filter media pads.

This filter also has different filter zones which promotes the beneficial bacteria in your pond responsible for phases of the nitrogen cycle. This action increases the conversion of the harmful ammonia in the garden pond.

5) OASE BioSmart Pond Filter

The following BioSmart pond filters provide both mechanical and biological filtration to ensure adequate oxygenation within the pond. There are two sizes available. The BioSmart 5000 Pond Filter is aimed towards 5000 gallon ponds, and the BioSmart 10000 Pond Filter is designed for 10,000 gallon ponds.

The filter foams provide efficient biological filtration due to their high surface area.

These models come with built-in cleaning indicators to alert you to when the filter requires cleaning. It also has a water temperature display, which is really useful.

These filters are quite pricey, but worth the expenditure.

OASE BioSmart 5000 Pond Filter

This 5,000 gallon pond filter provides for all stages of filtration for your pond. Not only does it complete the mechanical removal of debris, it then provides the biological filtration process to give maximum oxygenation. 

As the name suggests, this filter has been designed to service ponds of approximately 5,000 gallon capacity.

OASE BioSmart 10000 Pond Filter

As previously mentioned, this 10,000 gallon pond filter provides for all stages of filtration for your pond. Not only does it complete the mechanical removal of debris, it then provides the biological filtration process to give maximum oxygenation. 

As the name suggests, this filter has been designed to service ponds of approximately 10,000 gallon capacity. 

6) Aquascape Submersible Pond Water Filter 

Aquascape Submersible Pond Water Filter
  • Can be added to the intake of almost any submersible water pump resulting in crystal clear water and maintenance-free pumps
  • Contains ceramic filtration rings, providing substantial surface area for beneficial bacteria to colonize. The threaded intake and included multi-hose adapter ensure the filter is ready to Adapt to most pond pumps with a small piece of pipe or ¾” Threaded fitting.
  • Pre-filters pumps for reduced maintenance
  • Removable cage for easy cleaning
  • 3-year Limited Manufacturer

This filter contains ceramic filtration rings which provide a significant surface area to allow the beneficial bacteria to colonise.

It has a removable cage for ease of cleaning.

This filter can be added to the intake of most submersible water pumps, reducing the maintenance required. It comes inclusive of a multi-hose adapter and a threaded intake to ensure that the filter is readily adaptable to the majority of pond pumps.

7) Jebao UFP-2000 Submersible Pond UV Filter

Jebao UFP-2000 Submersible Pond UV Filter
  • EPA Establishment Number:97745-CHN-1; 13-watt Sterilizer
  • 4 Fountain Water Feature Attachments
  • Adjustment valve for regulating flow to fountain head and/or auxiliary water feature.
  • Includes a large coarse filter foam that water must pass through first and also three Bio filter media baskets
  • The unit is designed to run submerged so you do not have to worry about disguising it as you would with external filtration systems - a real bonus for smaller pond landscaping.

This filter is an ultraviolet sterilizer which kills algae, bacteria and parasites within your garden pond.

However, it also mechanically and biologically filters your pond too. It features a large coarse filter foam through which the water passes in order to mechanically filter the water before it enters the three Bio filter media baskets.

This filter is ideal for the smaller pond as it is designed to run submerged and is therefore inconspicuous and does not need to be disguised with planting.

8) Jebao CBF-4000 Bio Pressurized Filter with 13-Watt UV

Jebao CBF-4000 Bio Pressurized Filter with 13-Watt UV, 1000 gal
  • Ideal for powering streams and cascades and designed for a pond of up to 1000 gallons
  • Easy clean technology without opening the filter
  • Uv power: 13-watt 110-120v 60hz, one uv lamp was per-installed
  • Dimension: 9. 5" x 16. 5 inch tall hose adapter: 1", 3/4", 1/2"
  • Water pump and pond tubing sold separately

This is a medium-priced biological filter combined with ultraviolet technology for complete pond filtration. The UV sterilizer will bombard the water with UV light which will kill and bacteria or viruses in the water column. Bacteria and viruses are too small to be captured by the mechanical media, so will otherwise remain in the water unless treated.

The Jebao CBF-4000 is reasonably small and easy to conceal. It is designed for ponds with a capacity of up to 1,000 gallons, and is ideal for powering streams and cascades.

The water pump and pond tubing are not included, but are sold separately.

9) Jebao CF-10 Pressured Pond Bio Filter with 13W UVC Clarifier

Jebao 1000 Gallon Pressured Pond Bio Filter w/ 13W UVC Clarifier
  • Dual Filtration System to provide a Clearer and Healthier Pond or Water Garden
  • Cleans Ponds up to 1000 Gallons
  • Recommend for use with Pond Pumps Capable of Pumping between 850 to 1250 Gallons of Water per Hour
  • Inlet/Outlet Size:: 1/2", 3/4", 1" (recommend use 1" hose)
  • Backwash Feature

The Jebao CF-10 provides a dual filtration system designed to service ponds up to 1,000 gallons in capacity. It is recommended for use with pumps with the capacity to pump between 850 and 1,250 gallons of pond water per hour.

This pond filter offers three stage filtration. The first up is mechanical media which captures floating debris, then biological filtration which removes toxic chemicals such as ammonia and nitrate. Finally is the UV sterilizer, which kills and bacteria and viruses present in the water column.

Some users, however, have reported problems with leakage with this filter.

How to Determine the Required Size of Pond Filter

The pond filter you choose for your garden pond will play a vital role in the maintenance of a healthy and sustainable ecosystem within your pond environment.

A filter of the correct size and type will promote the healthy bacteria essential for pond and fish health, keeping the water clear and providing vital carbon dioxide for your plants to facilitate photosynthesis which, in turn, provides essential oxygen for your fish and other pond life.

In order to assess the size of pond filter you will need, the first thing to ascertain is the size of your garden pond, in terms of the volume of water.

This is very simple to calculate. Usually, the volume of any regular shape is calculated by measuring Length X Width X Depth so start by measuring these in feet. Once you have multiplied them all together, simply multiply this answer by 6.25 to give you the approximate number of gallons of water in your pond.

By way of example then – if your pond is 8 feet long by 5 feet wide and 2 feet in depth, then your pond is 8 x 5 x 2 = 80 cubic feet in volume.

The number of gallons in your pond is therefore 80 x 6.25 which =  500 gallons. As stated earlier, this is an approximation because home made garden ponds are often irregular shaped with variable depths, so it’s not an exact calculation.

Ready made garden pond filters have a flow rate that is measured in Gallons Per Hour (GPH). To calculate the filtration rate of a filter suitable for your pond, multiply the number of gallons in your pond by 1.5. In other words, you need a filter that is capable of filtering one and a half times the number of gallons in your pond per hour. In our example above, there are 500 gallons in your pond so you will need a filter rated at 500 x 1.5 = 750 Gallons Per Hour.

(You may want to convert your gallon calculation to litres in which case simply multiply the final gallon calculation by 4.5, so in the above example it would be 500 x 4.5 = 2250 litres.)

Cleaning Garden Pond Filters

We’re huge fans of garden ponds due to the environmental advantages they offer to amphibious and other wildlife, providing a rich and sustaining habitat to a variety of creatures. 

Although the addition of carefully selected pumps and filtration systems can greatly decrease the level of maintenance required, your garden pond will still need to be kept maintained to prevent it becoming overgrown with plants and weeds, and to avoid the water becoming clogged up with fallen debris which creates a very unhealthy environment for fish and wildlife.

When it comes to keeping your filter clean, your chosen product should come with specific instructions in this regard, as the cleaning requirements do vary between makes and products. That said, the increased bacterial activity during the warmer seasons means that cleaning will need to be more frequent during the warmer temperatures.

Regular cleaning and maintenance of your pond filter will ensure that your pond remains healthy and clean, and ensure the longevity of your filtration system. A little effort now will save time and money in the future.


Not all garden ponds will need a filtration system. If your aim is to create a wildlife pond and are intending to stock it well with aquatic plants, then you should be able to create a healthy balance naturally within the pond.

If you wish to stock your garden pond with fish, then you will need a good pond filter. We hope our suggestions above provide you with some ideas and clarity on the type of filter you need. It’s worth investing in an appropriate filter for the size and purpose of your pond – it will ensure the health and sustainability of your pond and the habitat it provides for your fish and the wildlife that make it home.

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Coral Realm

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