Reef Octopus MF-2000 Media Filter (OCT-MF2000) 4" diameter, 21.75" high & 5.5" x 5.5" footprint Requires: Your choice of media, a feed pump & hoses Recommended Tank Size: 375 gallons marine / 750 gallons freshwater Capacity: Holds approx. 1 gallon of media (depends on filtration media used and their manufacturer recommendations)