I have a shallow well 25'deep with a horizontal run to the house of 35'. I have a 3/4hp Flotec shallow well pump, and a 28# precharged tank system. My problem is that when it calls for water the pressure gauge surges 6-8 seconds @15# then picks up the water, but never gets higher than 25#'s for sometime,...........then it takes approx. 10 min before reaches shut down pressure. my check valve is in the house at the pump. Where should it Be? My contractor says its the pump and not the well. thank you for your time and expertise.