Beautiful setup! And I don't mean to be a rainy day on a wonderful parade-- but-- I have a 440 gallon also build by coast to coast. And it is serviced by two custom sumps from Advanced Acrylics ( duel protein skimmers and 3 socks in each unit). Your sump doesn't look large enough to hold the overflow volume potential. Hope that has been checked out with a 'simulated' power failure at full levels? JR