Brief description: I have a three tank system (A,B,C). Tank A is fitted with stand pipes with the over flow flowing down and then up through the bottom of a 1" bulkhead fitting and into Tank B. Tank B is approx. 12' x 2' x 12". At the end of Tank B is another 1" bulkhead fitting with the exit water going through 1" flex pipe down to the ground (2.5'), along the ground a distance of 5' and connected to the bottom side of a 1" bulkhead in Tank C. Tank B and C are the same level off the ground. The opposite end of Tank C has a bulkhead fitting with the exit water going down to the ground over to a pump and pumped back into Tank A. I'd like to use just one pump and gravity to move the water from Tank A to B to C. Water leaving Tank C going back to Tank A doesn't seem to be a problem (other than I have to throttle back the flow). And Water flow from Tank A to Tank B seems to be ok. The issue is getting the water from Tank B to Tank C. How can I increase the flow from Tank B to Tank C? Would a larger bulkhead fitting and transfer pipe work? I would like to use the principle that the water levels itself out between tanks kept at the same height. Can someone point me in the right direction?