another water preesure tank question

[dolfans]

My water will be normal and then higher pressure and go back and forth within seconds. I checked the air today and it is about 15 or so needs to be 28. It had water come out also. Is this normal? How can i tell if tank is bad? If good do i turn power off and drain all or 1/2 of tank and then add air or will water fill the bladder then turn power on? Anything else i need to know thanks

 

[johnjh2o]

If there is water coming out of the snifter valve on the top of a bladder than the bladder has failed and the tank needs replacing.

 

[Valveman]

Replace the tank and figure out what causes the bladder in the tank to break.