The Sun HW-303B external 4 stage canister filter is ideal for tanks up to 100 gallon. It handles up to 370 gallons per hour. The Sun HW-303B includes filter pads, hoses and all the parts you need to get started. The three flexible media trays allow you to add other filtration media such as Sun Sun's activated carbons, ceramic rings or bio-balls to achieve excellent mechanical, chemical and biological filtration. A built in 9 Watt UV sterilizer helps control algae spores/bacteria and promotes clear water. The HW-303B canister filter also has a convenient self-priming pump that eliminates the need for manual siphoning.