Most pumps ahve an inbuilt pressure switch which will switch the pump off under pressure (usually 60-100psi) Varistreams are good for reducing pump wear (as you can slow the pump down) and auto-compensate for working at increased height. As the varistream can sense load (excess current drain) on the pump it will switch the pump off before the pressure switch cuts in (or in the case of most Shurflo pumps the pressure switch has already been disconnected so no pressure switch wear), a worthwhile investment as it will save water, battery charge and reduce wear and tear on the pump. If you ave plenty of water to do all day anyway then I'd simply use an autostop hose connection as once you have disconnected it the pressure switch will turn the pump off anyway. One f our systems is set up this way with no problems for over a year.