Superfish Aqua-Flow 200 & 300 Easy Click Cartridge Specifically designed for the Superfish Aqua-Flow internal filter the Superfish Aqua Flow Filter Cartridge is an Easy Clean Click system making filter cleaning easy, replacing the cartridges in a flash. A dual-action cartridge, the Superfish Aqua flow Filter Cartridge consists of filter foam with a fully open-structure for perfect filtering, and Activated Carbon to remove organic contamination, chemicals and dyes from the water. It is recommended you replace your cartridge once a month. Remove the cartridge before administering medicines or chemicals, otherwise they will be absorbed as well.