Exclusively designed for Fluval aquarium canister filters, Fluval Bio-Foam performs exceptional mechanical and biological filtration. Bio-Foam's dense structure is very effective at trapping small particles that are not captured in the first stage of foam filtration.In addition, its intricate network of pores provides a large surface area that encourages the growth of helpful nitrifying bacteria, which is crucial for efficient biological filtration and goes a long way in creating clear and healthy water for fish and plants to thrive. Key Features : Exclusively designed for Fluval aquarium canister filters Performs exceptional mechanical and biological filtration Dense structure is very effective at trapping small particles that are not captured in the first stage of foam filtration Intricate network of pores provides a large surface area that encourages the growth of helpful nitrifying bacteria Crucial for efficient biological filtration Helps create clear and healthy water for fish and plants to thrive For freshwater and marine environments