I have read most of the other posts but couldn't find the answer to my problem. Problem- Water flow decreases to a trickle when using more than one faucet. Pressure tank is set at 38psi bladder (tank empty), 40psi pump on and 60psi pump off. I have a sediment filter and a softener on main outlet line. Pump cycles normally, does not short cycle. Tank does not seem to be very full after a pump cycle. Pump is a submersible about 80 feet deep and is about 8 years old. Would this be a tank problem or a pump/well problem?