Quick return plumbing question..

[gregghia]

I am plumbing a closed loop system. The tank is pre-drilled twice. The drain works with an overflow box. The return is standard 1" bulkhead. My question is what do I need to do for the return as far as PVC plumbing configuration? If I have straight PVC coming out of bulkhead into the tank and the pumps looses power, won't that essentially create a siphon?
When I checked out the LFS store they seem to have basic PVC coming from bulkhead with a non-glued 90 elbow to direction flow. Easy enough, my concern is the backflow in power loss.
Please let me know what to do... pics would help.

 

[fanker]

u mean the pvc in ur overflow? the stand pipe? i put a bull tee with a cap on the top and drilled a hole and put a 90 on the other end

 

[geoj]

In a closed loop system the water will level off, it won’t create a siphon because there is no place for the water to go but back over the overflow into the tank. If there were an open sump, then yes the water would siphon out and overflow the sump and floor.

 

[gregghia]

Fanker I meant the return. Its drilled glass so it opposite side of tank from overflow. The return PVC coming from glass returning water will be in the tank of course. Obviously when the pump stops and the water drains the suction will stop. I am just plumbing three tanks to one large sump so was concerned.