Penn Plax Cascade 400 Internal Bio Filter for Aquariums, 1-Pack
Bio-Sponge filter media works to keep your aquarium water clean & clear. Specially designed to fit your Cascade Canister Filter Pump, Bio-Sponge filter media optimizes the colonization of beneficial aerobic bacteria and removes ammonia and nitrites keeping your aquarium clean and healthy. Bio-Sponge filter media comes in various sizes made to fit your exact Cascade Internal Filter Pump.