Replacing water pump

I have a shurflo and have replaced the pump once and installed the valve area twice due to water coming back from the line past the pump, filling the tank then overflowing through the water input for the tank. I have had no problem getting the pumps to prime except only with one of them. I had finally installed a shut off valve directly after the pump so water does not flow past the pump filling the tank when not in use. I tried a check valve one time and it failed. No matter what type of pump you choose, I think the shut off valve installed after the pump will act as a good safety. Then when you plan to use the pump, just open it.