Fluval Bio Max Media 11.1 (Fluval A-1456) for all Hagen Fluval filtersMiddle or Bottom Media BasketsFor freshwater and marine environmentsFluval BioMax ceramic rings have a complex pore system where beneficial bacteria can thrive. With more capacity than most biological filter media, BioMax helps reduce ammonia and nitrite. Plus, the rings allow ideal water movement throughout the media, to ensure optimal contact time for efficient biological filtration.