Just another thought.
I misread the original question and assumed he already had a working pressure system and just wanted to supply water to an open tank. That would be no different than a bathroom stool, which is an open tank with a float valve. Now I see where he wants to switch a pump on and off to control the fill.
Another avenue might be to just go ahead and install a pressure tank with associated pump switch so you have a real water system. Then Cecil would have water supply at any tap point he wanted.
Then a simple float valve would control the water to his open tank, but he could add any number of valves/circuits in the future very simply. Good for future projects.
If he is trying to turn on and off a 2 horsepower pump to only supply a few gpm, that is akin to filling up your tea glass with a fire hose. Cycling that big of pump each time a small amount of water is not going to be economical electric wise or good for the life of the pump motor, IMO.
Am I off base here?
Last edited by snrub; 12/19/13 08:18 AM.