I don't have a sump yet, but I have planned something for when I plumb a new tank onto my system. It'll be laser cut from acrylic. I am just waiting for shutdown to end so I can get the vector file to the laser cutters. This sump will have two downpipes each for the two systems. I'll be running a modified bean animal overflow, where instead of the second and third redundant pipes running separately, I will join them halfway down with a Y-piece fitting.