Pond Filters & Filtration Systems

Pond filtration explained

Clear, healthy pond water depends on three stages working together:

Mechanical filtration traps leaves, fish waste and debris.
Biological filtration grows bacteria that turn toxic ammonia and nitrite from fish waste into less harmful nitrate.
UVC clarification clumps free-floating algae so the filter can catch it, clearing green water.

Choosing a pond filter

Pressure filters: sealed units that can be partly buried and still pump water up to a waterfall.
Flow-through / waterfall filters: gravity filters placed above the pond, returning water as a cascade.
Underwater filters: sit inside the pond, suited to small ponds and features.
Drum filters: self-cleaning mechanical filtration for koi and large ponds.
UVC clarifiers: add UV to an existing filter.

Sizing a filter

Filter ratings usually assume a pond with few or no fish. If you keep koi or a lot of goldfish, choose a filter rated for at least double your pond volume. A new filter takes several weeks to build up bacteria. Add beneficial bacteria to speed this up.

Brands we stock

We carry OASE filtration (including FiltoClear, BioPress, Vitronic and Bitron) and PondMAX PF UV pressure filters sized for 2,500 to 30,000 litre ponds. Match your filter with a filter & watercourse pump and keep spare filter media on hand.