ok first off what you described with the pvc tubing is NOT ebb&flow. what you described would be a recirculating drip system. I would not run that constant, at 1 gph I would say 3-4 times a day at 15-30 mins each. Second off you say "My current grow is DWC: No drip, but pumps (un-regulated) on a cycle of 15 min on, 2 hour off, and Im not sure of the un-regulated pressure of the pump." What exactly is that pump doing?? In DWC the only pump you have is an air pump providing air to the roots 24/7 so the plant doesn't drown. Please enlighten us as to how your system works