I want to build a pump system using the water pressure from a 36 inch deep pond (up to 96" weather permitting) to pump water to a holding tank 100 feet above the 36" water level. after reading thru 15 pages of posts "water pumps" etc. on PF my head is spinning. At the dam there is access to a 6" drain supply 3 ft. below the water level. If I use a 100 ft. length of .750" plastic water line, i calculate i will need 19.13 psi (+ friction loss= ?). A 6" pvc pipe used as the cylinder is 5.50" ID. ,with a bobin piston and the addition of two 2" supply check valves and two .750" outlet check valves (one each at each end) I calculate around 30.64 psi.out of the homemade pump. If this is correct I will probably go to an 8" dia. pipe to cover any of my guess work. Is this plausable or am iI dreaming? Any comments would be much appreciated.