[geekdafied]

Well here is some info I got from a buddy of mine thats a hydraulic engineer in reguards to aquariums...

Total maximum drainage:
3/4"-700 gph.
1"-1000gph.
1 1/4"-1200gph.
1 1/2"-1500gph.

Dersa/Durso standpipe will increase it by 20%.

Coeficient of friction:
Every 22, 45, or 90 degree bend adds friction slowing maximum possible drainage 90 degree bends can also result in bubbles gurguling trying to escape drag.

Head Pressure:
Every vertical foot=1ft head pressure
Every 3 horizontal feet=1ft. head pressure
Every 90degree bend =1.5 ft. head pressure.