This CNZ HW-304B 525 GPH 4+1 filtration system is ideal for fresh and saltwater aquariums up to 150 gal.. The integrated 9 watt Sterilizer helps keep your aquarium healthy and crystal clear. The HW-304B defies its low price because it comes equipped not only with a built-in Sterilizer but all the necessary plumbing for installation and includes four large filtration media compartments allowing you to add the filtration media of your choice. The filtration media trays offer a fully customizable filtration system to suit your specific aquatic needs. The HW-304B includes four fine filter pads (white) and a single coarse filter sponge (blue) for enhanced Mechanical Filtration. with the addition of Premium Activated Carbon, Ceramic Rings, or Bio-Balls , you'll achieve superior filtration and crystal clear aquarium water. The HW-304B Canister Filter has a convenient Prime Pump that eliminates the need for manual siphoning! Say goodbye to a mouth full of aquarium water!!!