System has submersible pump and pressure tank with bladder. My problem seems to be a waterlogged tank. System turns off and on every few seconds. The water comes out of the faucets in spurts. I turned the power off to the pump, opened the valve after the pressure tank and drained the water, I also applied air pressure to tank to force the water out, the water looked very brown and rusty, the tank is only about 18 months old, I checked the air pressure, (it was zero), I shut off the valve to add air to tank until 2 psi below pressure switch setting, my problem is I don't know what the pressure switch setting is or how to find out. I was told to use 28 psi as a guess. I don't think I should guess. After draining tank I turned the system back on and it works much better but not proper. Now what should I do to get the job done right.