We have a submersible well pump with a bladder pressure tank. A couple weeks ago the water pressure was pulsating. My brother added some air into the tank and the pulsating stopped. Saturday I turned on the water and the pressure was very low. It continued to decrease each time the water was used until finally no water was coming out. My brother replaced the pressure switch on the tank, and still no water. He tested the well pump and it wasnt working properly, so he replaced the well pump and the wire. When we put the pump back down in the well and turned the power back on, the tank filled and we had water. But once we turned on a faucet, the water pressure droped and the tank didn't fill back up. We have pulled the well pump out 3 times, and everytime we put it back in the well, it does this same thing, the tank fills once, then stops and doesn't refill. We are stumped and have no idea what the problem could be. Any ideas??