i'm in the process of setting up my 300gallon arylic, it's 8'x30"tallx24"deep. So you tank sounds about 360 or so. ....I just built my refeg a couple days ago its a 90 gallon glass tank 48"x24"tallx18"deep. first chamber is approx 6" for crushed coral, than 20" or so for live sand and rock...