Overflow Plumbing

[magnon]

I just got my 125 tank back after being drilled and bulkheads installed. I am also building overflows out of 8" PVC like Travis's thread. What I need now is recommendations for plumbing the overflow line from the bulkhead (1" with slip on on the outside) to the sump. I am particularily interested in where to locate the ball valves and unions for ease in disassembly and maintenance. Sketches would be great. I know there is a lot of info out there but I haven't been able to find what I need.

Thanks for the help,

Gene