Aqua One 402s Black Sponge Pads – For Advance 550/750 Canister Filters – 2 pack

A new 402s twin pack of black fine Aqua One Sponge for the Aqua One Advance 550 and Aqua One Advance 750 external Canister filters. Open cell foam makes superb water filtration material because it both traps debris and acts as a good home for nitrifying filtration bacteria. Rinse the foam in your filter in some aquarium water only. It is not desirable to get the foam absolutely clean but rather to remove the majority of the waste matter so that water can flow through it easily. After a few months of use and washing the cell structure of the foam starts to collapse and it needs more and more cleaning. This is the time to replace the foam with new pieces.