Water pressure goes up and down. Husband let air out of tank, then when he went to drain tank water shot out of valve on top of tank. Now we can not get water. Do we need to replace the tank, or can something else be the problem? He has put pressure back in tank and water, but now pump clicks on and off.

The neoprene membrane in the tank has ruptured. The tank will have to be replaced. When you replace it adjust the air pressure to 2 PSI under the cut-in of the control box. In other words if your control box is set at 20 PSI cut in and 40 PSI cut out the tank pressure should be set at 18 PSI. Good luck, Tom