Can anyone help I'm at my wits end, I have 2 shurflo pumps my problem is ,to start, I thought it was clogged with resin(before anyone starts I have a strainer fitted)so I took it home opened it up but it was clean, so I fitted the spare but same problem, so I thought airlock, did the take the hose off the outlet put the pressure up to 99 and shook the tank no joy and now I'm totally lost as to what it is . It must be simple but I'm just not seeing it. The water is flowing into the pump just nothing is coming out. Your help would be much appreciated.