Water = 62.4pcf (pounds per cubic foot). One foot of water... 62.4/144 = 0.433psi. You can do the rest.

John... as a soils engineer, I use the above just because it gives me a better "feel" than your method of calculation.

So... a quick and dirty solution is to feed the tank with a hose with a valve on it. It takes time to stand there and do it, but it will work until you have fixed the pressure regulator in the tower.