Scott's 270g aka Project Mayhem

[Scythanith]

Originally Posted by FishyFishy!

Can you run a simple check valve right after your pump? A george fischer wye check valve would be very effective and wouldn't limit flow very much.

It's not backflow through the pumps, its the actual water volume from the display tank that is above the weir teeth draining into the sumps.When the top sump return pump is running, it raises the level in the main tank by ~1", the lower pump replenishes the top sump and makes up for any discrepancies in water height (usually due to evaporation). I already have a GF wye on the lower sump pump, so nothing drains back through it.