That's a fair point, QA, I'm probably getting sub-optimal performance from my pump. I've got 45ft suction hose with probably 10-15ft head lift plus probably 100-125ft of discharge hose.
HOWEVER... the biggest issue with what we're discussing is that my pump is not rated to 18,000gpm!! That would be impressive indeed. I'm afraid it's only rated to 18,000gph (technically 317gpm). A fairly critical typo in my original post! (now corrected) Sorry about that.
I've got probably about 2.2acres watershed, but in the worst possible case, about 4.2 acres - in a developed residential area, google earth calcs attached.
