Interesting. One thing about having the QT tanks below the sump is that when it's time to acclimate the new arrivals, you can feed the QT water from the sump through a float valve.
I have a line going from my fuge that is above my tank level, to a valve, and then adapted to JG 1/4" line to a float valve on my QT. When it's time to acclimate, I open the gate valve, and slowly remove QT water one qt. at a time. Over a period of multiple days, the new arrival becomes completely acclimated to the display system, and then I pop it in the main after lights out.