Originally Posted by scottayy
Not if I used a check valve on the return line, right? I'm familiar with sumps and siphons and back-siphoning. But a check valve only lets water flow one way.
I'm just wondering which placement would be best for best water circulation?
Correct, but again, not if the check valve fails (which does happen - granted rarely), but it only takes once with a saltwater system to loss 100s if not 1000s of $, why take the risk?