Sunsun filters include the starter 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 Sunsun's activated carbon, ceramic rings or bio-balls and are also included to achieve excellent mechanical, chemical and biological filtration. The HW series of filters all have a convenient self-priming pump that eliminates the need for manual siphoning. HW302 (264gph, up to 75 gallon) HW303 (370gph, up to 100 gallons) HW304 (525gph, up to 150 gallons)