I have a Signature 2000 Fiberwound Pressure Tank. Model SR85-25-01 I have lived in the house I built since 1990 . Replaced original tank about 10 years ago. Bladder leak. The water pressure had had a notable drop when another faucet is being used. Just today I could not get the how water faucet in the upstairs bath room to even produce water. Is it my bladder or well pump? What the procedure to checking pressure of tank?