PVC Backflow preventor

[muck]

I would run the return over the back of the tank or up through your overflow box and have the return near the top.

If you want to run the baffle system still put it on a closed loop. No worries about backflow and syphoning then. Only downside is you need another pump.

[danny zubot]

After reading the post again, I realized that missed this part.

My return line comes in at the middle of the tank on the bottom.

In that case, please don't take my advise.