Cermedia Marinepure 1.5-Inch Sphere Bio-Filter Media For Marine And Freshwater Aquariums, 1-Gallon

Ceramic Bio-Filter Media with Vast Surface Area & Open-Flow Porosity. For ammonia & nitrite removal in fresh & marine aquariums. One MarinePure Sphere has the same surface area as 1350 plastic bio-balls. Use in wet/dry filters sumps or canister filters.