He would be a LOT better off to attach the OUTPUT of the Fluval to the UGF plate and run it in a reverse flow arangement.
Why?
Because you'll be running already filtered water through the ugf plate so it wont clog and the reverse flow will lift debeis out of the substrait and allow the intake to pick it up.
Warn him that he will be dropping the flow rate on the fluval slightly depending on the tank depth and should run a size larger than he really needs.