I went with a Red Sea 625G2+, but shortly after they released both the S650 and the new IM EXT tanks which was a slap to my face because I would have easily went with one of those instead. The IM EXT tanks are a bargain for their build quality and features. Go EXT for sure. You’re going to regret the blocked flow from the overflow box (although they angle it in the INT). EXT all the way.