Canister lids ensures water tight seal. The polishing filter pad acts as a water polisher removing fine debris. The bio-filter balls and ceramic rings provide a large, multifaceted surface area for the growth of bio spires. Black Diamond Carbon Removes odors, discoloration and water impurities. Filter Foam pads screen out dirt and debris. The Magniflow Canister Filter 220 uses a powerful, three stage filtration that is ideal for both fresh and saltwater aquariums. This multistage filtration ensures a clean and healthy aquatic environment.