Fish Filters and Media

A small, focused set of eight products: aquarium filters for nano and small tanks, two pond multi filters, and the chemical media that goes inside a canister. Hydor internal filters, an AquaClear power filter, Blagdon Inpond pond units and API filter media make up the range, covering freshwater, marine and turtle setups.

Mechanical, biological and chemical filtration

Every filter does up to three jobs. Mechanical filtration traps solids on sponge or floss, and that is the part you rinse regularly — in old tank water, never under the tap, so the bacteria living on it survive. Biological filtration is those bacteria: they colonise sponge and ceramic surfaces and convert ammonia to nitrite and then nitrate, which is why a filter should never be stripped and replaced all at once. Chemical filtration is the optional third stage, where a medium such as API Activated Carbon or the API Bio Chem Zorb pouch adsorbs dissolved organics, discolouration and odour. Carbon is also the thing to remove before you dose a water treatment, because it will pull the treatment straight back out again.

Matching a filter to the tank

Internal filters mount inside the tank and suit nano and small setups, or anything shallow. The Hydor Pico is rated for aquariums and turtle tanks, where a low water line rules out a hang-on unit, and the Hydor Crystal runs a two-stage cartridge for slightly larger volumes. A power filter such as the AquaClear CycleGuard hangs on the rim instead, holds more media and is easier to service without putting an arm in the tank. Marine tanks add a fourth option: a protein skimmer like the Hydor Slim Skim Nano lifts dissolved protein out as foam before it breaks down into nitrate, a job no mechanical medium does. Ponds are a different scale again, and the Blagdon Inpond 5 in 1 and Inpond 6 in 1 9000 combine pump, filtration, UV clarifier and fountain in one submerged unit. Size any filter by turnover — several times the tank volume per hour is the usual starting point — and remember that stocking level and feeding matter more than the litre rating on the box.

Brands stocked

Hydor covers the internal filters and the nano skimmer, AquaClear the hang-on power filter, Blagdon the two Inpond pond multi filters, and API the loose chemical media in activated carbon and Bio Chem Zorb pouch form. Chemical media is the part of a filter replaced on a schedule rather than rinsed, so a spare pouch is worth keeping.

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