Eshopps Channel Design (ECD, Patent Pending) Unique Three Water Channel Large Skimmer Compartment & Viewable Refugium in Front Built-in Probe Holder & Float Valve Removable shelf Quiet Operation Dimensions: 36"x16"x16" Skimmer Compartment: 16x15.5" Return Compartment: 8.5"x8.5" Refugium Compartment: 12"x8.5"