Last year we installed a new bladder holding tank. Pressure set at about 27 lb since pump turns on at 30LB. After installation pump was running a long time to fill pressure tank. If drawing water from multiple sources at one time once pressure dropped and pump went on it could not supply enough water. Installed new jet pump. Problem still not solved and has gotten worse. It is taking 5 minutes to fill bladder tank even with all water turned off once we hear pump kick on. Pump shuts off when gauge at 41 LB which I am not sure why because I thought it was a 20 LB differential so was expecting 50LB shutoff. When installing new pump noticed that galvanized pipe in check valve looked restricted. This weekend dug up entire 50 foot section of incoming line and replaced galvanized 1 inch line with poly. Pipe was not as bad as we had hoped so problem still exists. Also should mention we are getting some air in system which comes out of taps at times. Well may be 40 to 50 years old not sure. Could there be any other explanation except for a bad well?