Aqua Care Internal Bio Clear Power Filter BC450Aqua Care Internal Bio Clear Power Filter BC450 Aqua Care Bio Clear Filter For Aquariums Four layers of filtration helping to maintain a healthy environment for your fish! Mechanical Filtration by filter sponge and fine pad of the cartridge Chemical Filtration by the activated carbon trapping particles and removing odour. Biological Filtration by the ceramic rings providing large surface area for beneficial bacteria to grow. Replaceable cartridges