Biological Pond Filters

Biological Pond Filters, Moving Beds and Bakki Showers

Biological capacity should follow fish and feeding, not pond litres alone

A biological pond filter gives beneficial bacteria the oxygenated surface they need to process ammonia and nitrite. The difficult part is that two ponds with the same volume can place completely different demands on the filter. A lightly stocked wildlife pond and a koi pond fed several times a day are not comparable, so we size biological filtration around fish mass, feeding and water quality as well as litres.

This category includes complete Burtons biological chambers, open Bakki shower systems, moving-bed modules and the media used inside them. The Burtons FB 600 and larger FB chambers provide dedicated biological stages; the Burtons Bio Tank 1200 forms part of a modular filtration installation; and a three-tier Burtons Bakki Shower exposes water and media to a high-oxygen trickle flow.

Moving bed, static bed or shower?

A moving bed keeps suitable buoyant media in constant motion with air. It is compact, well oxygenated and forgiving when correctly designed. Static or fixed media can combine biological surface with some particle capture, but it needs a cleaning plan. A shower filter provides strong gas exchange and oxygenation, but it returns water above pond level and is visually and acoustically more noticeable.

Mechanical filtration protects the biology

We rarely look at a biological chamber in isolation. A drum, sieve, settlement or other mechanical stage should remove as much solid waste as practical before the bio-media. Otherwise the biological stage collects dirt, consumes oxygen and becomes harder to maintain. The right answer is a balanced chain of equipment, not the largest tub of media available.

The Biological Filter Products in This Category

Burtons bio chambers and Bio Tanks

Burtons FB chambers and Bio Tanks are intended for larger koi and pond systems where biological volume needs to be installed as a proper stage rather than squeezed into a small all-in-one filter. Compare chamber dimensions, connections, media allowance, required aeration and the space needed to isolate and service the unit.

Burtons Bakki showers

Plastic and stainless steel three-tier showers are available in several widths. Water is distributed over shower media and exposed to air as it falls through the tiers. They can provide excellent biological performance, but the pump must deliver the required flow at the raised inlet and the return needs to be planned for splash and noise.

Oase ProfiClear moving-bed modules

The ProfiClear Premium XL Hel-X Moving Bed Module and PondPads version integrate with the Oase ProfiClear XL system. These are not generic tubs: the module, media, air and upstream drum stage are designed to work as a matched commercial-scale filtration line.

Biological media choices

Evolution Aqua K+, Aqua Source BIOFLO and Biopipe+ are moving-bed carrier options, while block, tube and shower media suit different chambers and flow patterns. Surface-area figures are useful only when the media is used in the way it was designed.

Our advice before upgrading the biological stage

Test ammonia, nitrite, pH and alkalinity and look honestly at the mechanical pre-filter. If the present bio-stage is full of sludge, adding more media may not solve the underlying problem. We can help work out whether the missing piece is biological volume, oxygen, flow or solids removal.

Keep exploring: Pond filters · Pond filter media · Drum filters · Pond air pumps · Water testing

Biological Pond Filters FAQs

What does a biological pond filter remove?

It processes dissolved ammonia and nitrite through established bacteria. It does not physically remove all solid waste or suspended algae.

What is a moving-bed filter?

It is an aerated chamber containing buoyant media that tumbles continuously, maintaining oxygen and exposing the biofilm to passing water.

What is a Bakki shower?

It is an open trickle filter where water passes over shower media through stacked tiers, providing strong oxygenation and gas exchange.

Do I need mechanical filtration before a bio chamber?

Yes, in most koi and high-load systems. Good solids removal stops the biological stage becoming a dirty settlement chamber.

How much moving-bed media can I put in a chamber?

Use the chamber and media manufacturer’s permitted fill. Overfilling prevents proper movement and reduces effective oxygenation.

Why does a moving bed need an air pump?

Air keeps the media circulating and supplies oxygen for the nitrifying bacteria.

Can I add new media to an established filter?

Usually yes when the chamber has capacity, but new media still needs time to develop mature biofilm.

Should I use the maximum pond-size rating?

Treat it as a best-case reference. Fish load, feeding, sunlight, depth and maintenance all affect the sensible working size.

What is the difference between mechanical and biological filtration?

Mechanical stages remove solids. Biological stages provide oxygenated surfaces for bacteria that process ammonia and nitrite. A good pond system normally needs both.

How long does a new biological filter take to mature?

There is no single date. Temperature, pH, oxygen and food load all matter, so test ammonia and nitrite while the system settles.

Will a bigger filter cure green water?

Not necessarily. Green water is usually dealt with by a correctly sized and maintained UVC working with suitable filtration and flow.

How often should pond filters be cleaned?

Clean according to restriction and waste load rather than a rigid calendar. Mechanical stages need attention before they choke; biological media should be handled more gently.

Can I wash biological media with tap water?

Avoid heavily chlorinated water on established biological media. Use the cleaning method recommended for the exact filter and media.

Does the filter need to run continuously?

For a stocked pond, biological filtration and circulation are normally continuous during the active season. Follow the equipment and winter-management instructions.

Can you check whether a filter will suit my pond?

Yes. We will want the real pond volume, fish stock, feeding, existing pipework, pump position and preferred maintenance routine.