What's the best way to prime this system? I've just bee hooking the hose to it and back feeding it to build the pressure up then turning the pump on because I've been leaving it unplugged. Is the pump suppose to cycle on occasionally to maintain pressure or is it suppose to stay primed? I've cut off the valve to the field and it still cycles on every once and awhile when the pressure drops. It may ran once every 15 to 30min to keep pressure is this normal?