Keep your tank water clear and comfy with the Zoo Med Nano External Canister Filter. This powerful filter employs three highly effective stages of filtration to help keep your water clean and your fish happy. The biological stage offers an ideal surface for beneficial bacteria to grow. In the chemical stage， activated carbon works to remove discoloration， heavy metals， odors and organic waste. Last but not least， the mechanical stage traps harmful debris like uneaten food and waste—then returns clear water back to your tank. The Zoo Med Nano External Canister Filter is designed for easy installation， operation and maintenance. It comes with everything you need to get started and features an easy-open filter head to make cleanups a breeze. Plus， anti-vibration bushings ensure near-silent operation for a truly serene tank.