Eshopps RS-75 Reef Sump - Up To 75 Gallons - 18" X 10" X 16" Sufficient, usable sump area to accommodate skimmers, pumps, and other additional aquarium devices Prefilter sponge to keep debris and air bubbles from getting into the pump Open-top design allows easy access for convenient equipment maintenance Easy Removal of Micron Bag Dimensions: 18" x 10" x 16"; Skimmer compartment: 8" x 9.5"; Return compartment: 3.5" x 9.5"; Micron Bag: 4 inches