The Sun HW-303a external 3 stage canister filter is ideal for tanks up to 90 gallon It handles up to 370 gallons per hour 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 (each sold separately) to achieve excellent mechanical, chemical and biological filtration The HW-303B canister filter also has a convenient self-priming pump that eliminates the need for manual siphoning