Fluval EVO/SPEC/FLEX BIOMAX Filter Media. BioMax provides effective biological filtration, which helps eliminate fish waste and results in a healthier overall aquarium environment. Key Features : Provides critical stage 3 biological filtration Large surface area provides optimal colonization of beneficial bacteria Enhances the elimination of fish wastes, resulting in a healthier aquarium environment BioMax is suitable for: SPEC 2.6 G (10 L) SPEC 5 G (19 L) EVO 5 G (19 L) EVO 13.5 G (52 L) aquarium FLEX 9G (34 L) FLEX 15G (57 L)