here's a crude pic of how I did the overflows
It is well sealed around the bulkheads, but I left enough volume in my sump just in case the water level dropped to that of the bulkheads. I do not, however, anticipate that happening.
Yes, John, I had to stick a few PH's in the tank for that extra boost. Too bad because I hate to look at that kind of stuff!
I will be moving in the next few months, so I just might fab up a new backdrop with a few minor changes.
1. I will do some experimental testing with return flow and the resulting currents for optimum turbulence (sounds geeky, eh?) So I can bury it in the wall and not have to look at any more PH's.
2. I will integrate more depth into the wall for bigger ledges.
3. I want to wrap the wall around the sides for a more 3D look (from back top to front bottom diagonally).
Other than that, I am totally happy with the way everything's worked out! Rich.