I don't currently have a tank. I'm in the r&d phase of a large scale tank. I'm planning a 700gal built in reef witha 300gal sump. I'm currently working on cutting new 14" deep trenches into my basement floor to allow for the weight of the support beams as my tank isn't going to be on the ground floor. I'll be doing 14" thick footers with steel I-beams bolted to the footer and the floor of the room beneath the tank. I'm plumbing the overflows through the floor so that the sump and all equipment can be housed in an equipment room in the basement that will be equipped with a floor drain to help facilitate easier water changes.