two displays, 3 surges, 2 sumps, 2 refugiums (or how to flood a basement?)

[golf nut]

I would seriously oversize the overflows in the DT, when either of those surges kick in they will become siphons and dump very quickly a 2" siphon will be too much for a standard 1 1/2 drain even if you have two of them, unless there is a ton of room in the display to handle the new volume of water rushing in.