i'm going to build my overflow box today ... it is for a 24" cube tank.
i plan on using a mag12 for my return. it will prob be a pretty straight shot back up to the tank with 1 90 degree bend and travel up ( on an angle - which i included as a 45 degree bend ) about 57 inches. the reef central head loss calculator came up with 759 GPH. the RC overflow calculator recommends a 12" overflow.
so... i was thinking that an overflow box of 12H x 7W x 4D ... would this work ok?

Edited by coreyk