Running closed loop from sump?

[mark]

Wouldn't be a CL as inlet and outlet at same head for CL, but no reason wouldn't work assuming your overflows can handle it, just more flow through the sump and depending where the outlets are in the tank, risk on siphoning back to the sump with no power. Same idea as a bigger return pump with multiple outlets.

Nice thing about a true CL is no head loss and can have returns low without risk of flooding. You don't have to drill as can do CL over the top.