What causes the water in the pressure tank to rise above the float, even collapsing the float periodically. Needing to be totally drained every 2 months to reestablish proper pressure. Has been this way since newly drilled. Currently running constantly but never above 30 psi . Well is 6 years old. I realize the pump is probably stopped up with rust or motor is too weak to maintain pressure,but if I pull and replace I would like to know how to fix the other problems
