Does anyone have any data on how much GPH is reduced due to back pressure using the Custom Aquariums Siphon Stopper? I'm considering using two of these on a Innovative Marine 150 EXT. I've had a sump overflow in the past using the drilled hole at the water line due to debris blocking the hole. On my current tank I use a reverse check valve that has been working flawlessly for years, but this tank will be in an office viewable from the living room and there will be no canopy. I don't want any of the plumbing viewable.