Got the Overflow

[jim692]

InfernoST,
I like the layout and would use layout # 2.

I think BigJim and CaptainAhab are right about the flow rates however. The table from flex PVC seemed very optimistic to me. The length of pipe, fittings, and bends all affect the flow rate. Also, any build up on the inside of the pipe will reduce the flow rate.

Your 1" PVC will flow about 510 gph (8.5 gpm) at a velocity of 3.5 ft/sec. The chart you were using assumed a 6.0 ft/sec flow rate which I believe to be overly optimistic. (BTW a 4 ft/sec flow rate gives the approximate 600 gph (580 gph) everyone quotes.)
A 1-1/4" pipe would allow about 920 gph at 4.0 ft/sec and about 800 gph at 3.5 ft/sec which I believe is a more realistic number. 1-1/2" would give you 1150 gph at 3.5 ft/sec.

I think a real world test of your overflow box ( say 2 - 5 gal. buckets of water timed through the overflow) would be a good idea to make sure it will perform as you want.

Good Luck

[InfernoST]

Thanks for the input Jim. That's good info, what ever the actual flow rate is, what it is now is plenty. My pump is pushing about 550 gph (Being on the conservative side) and neither one of the main valves is not near being fully open. I'm pleased with the performance as is and still have headroom if I want to increase the flow but I don't feel that will be necessary. I did do a test with straight 1 inch pipe into a 17 gallon tub and it took roughly 1 minute (Give or take) to get 15 gallons from one tub to the other before the siphon broke. I should of tested the overflow, maybe next time.