Auto Water Change, plus, ATO, plus Two Aquariums, plus A Shared Sump, plus A Shared Refugium. When I set up my 120 Gallon, I’m think about setting up the above. The Sump and Refugium would go behind the wall under my Basement Stairs. My Replacement Saltwater would be in a 45 Gallon AGA Aquarium that I already have. I would still do my mixing in a Brute Container. The Aquariums would be the same surface height with each other, and the Sump and Refugium would also be the same height with each. I always do a full quarantin, on new livestock. I’m trying to figure out if there would be any other problems. Also I have a Gen-X pump I’m hoping I can finally use. Also I need suggestions on Auto Water Changers