Aqueon QuietFlow Bio Balls Filter Media is biological filtration that improves the overall water quality for fish. The geometric surface area is ideal for beneficial bacteria growth for a healthier aquatic environment. Safe for use with freshwater or saltwater applications this filter media can be used with various fish tank filters including hang-on-the-back, internal, canister and sump. For use with freshwater or saltwater applications Improves overall water quality for fish Ideal for beneficial bacteria growth Permanently bonded hose ends Can be used with various fish tank filters