I have a 1 hp Gould pump and Champion Tank. The pump is about 5 years old, I'm not sure how old the tank is. Last night we lost water pressure so I went out to the pump to check it out. The system guage showed zero pressure. This morning I got up and turned on the water and everything seemed fine. I took a 3 minute shower and after that lost pressure again. Went outside checked it out and had 10 lbs. of pressure. This afternoon I had 15 lbs. I shot the pressure switch contacts with compressed air, ran all the pressure out of the system and checked the pressure on the tank. The tank has about 35 lbs of pressure. No sound comes from the switch or the pump. Any suggestions?

Thanks