Fluval FX Series Bio-Foam For FX4/FX5/FX6 Canister Filters

Replacement foam filter pads sized for the FX4, FX5, and FX6 canister filter series, handling the mechanical filtration stage that traps debris before water reaches the biological and chemical media. Foam filtration media should be replaced periodically as it becomes compacted with debris, since a clogged foam stage reduces flow rate and filter efficiency across the whole canister.