Interpet CF2 Aquarium Filter Replacement Media - 3 Month Service Kit Includes 3 Floss/Carbon Pads and 3 AlgaepadsThree month service pack includes:3 floss pads which contains carbon in the middle for both biological and chemical filtration3 algae pads to reduce unsightly algae.The Interpet Internal Cartridge Filters are a new and exciting range from Interpet, allowing you to change filter media with a simple click in cartridge.Suitable for coldwater or tropical aquariums, the CF range is an easy care filter, which effectively keeps your tank clear, clean and healthy.Aquariums are a closed system and any waste or dirt produced by fish and plants remains in the water. A filter is thererfore essential for trapping this dirt, breaking down toxic fish waste and removing algae, and for circulating and oxygenating the water.