Well on my way home tonight I decided to stop by Fin and Feathers to explain what was going on to the guy who told me how to build it. He is telling me exactly what you have said here, and that I need two pumps to accomplish my needs. Seems he thought I was ONLY talking about the closed loop system, and was not addressing the sump at all.
I think I am on the right track with what I need to do, and it seems the only thing I am missing outside of a few new plumbing parts is a new pump to return the water back to the tank.
The current pump is going to be in a loop with four exhaust, and four return bulkhead fittings, all located near the bottom of the tank. The two drains I have near the top will still return to the sump, but I am needing to add in two other returns to return water from the sump.
To answer your question about tubing, I am using 1 inch schedule 40 PVC.
The other question is yes, I am using a check valve, which of course will move from the closed loop side to the sump side.
I'm guessing I should probably add in a second one, and just leave the one I have so no water [or sand] ever goes back to the pump. Is that right, or not needed?
So now my question is, what am I going to need in the way of a pump to return water from the sump to the tank, and how large should the lines be?
That I could use advice on. How many GPH should I need, and do you have a link for a suggested pump?
Now I'm really feeling like a tool, and the reason I waited 9 months to post.
Thanks in advance guys and gals!
Chewy