Originally Posted by DanS180
i cant seem to grasp your concept lol im sorry, which numbers???? hahaha
Put one at #4 and one right before the first elbow. The one closest to the pump under the tank. So the tubing would come out of the pump and go up, just before the PVC
turns add the first check valve. It should be a couple inches above the water line.
Now having said all that, your plumbing may be more complicated then it needs to be. The ball valve will be crazy hard to reach in the back. You should be able to keep all the PVC
under the tank with the exception of the one line going to the back hole. That would mean that the plumbing would start at the pump, go up, then a check, then an elbow sending it left towards the return under the tank. A "T" would send it up to the first return with a ball valve to control flow there, and the other part of the"T" would send it back to the second return. That low return would start with a ball valve that would be horizontal so you can reach it from under the tank. When the low return turns upward you add the other check valve. This would give you a safe return system that would be easier to reach once the tank is in place. Does that make sense? I know this must sound complicated by text. Ouch!