Precharged bladder tank lost air
When faucet is turned on, I get a surge condition, water flows but the pressure gauge alternates back and forth rapidly. I turned off the power, opened the outlet valve and just a little bit of water drains out. I also checked the air valve stem at the top of the tank and found no air pressure. I removed the valve stem and no water came out.
No air was in the tank. I kept the outlet valve open, pumped air and checked the pressure until 40 pounds was reached. As air was put into the tank, more water flowed from the tank outlet valve. The surge condition stopped but now I do not know why the precharged air disappeared and where did it go? What is the diagnosis of losing the recharged air in the tank? Does it mean that the bladder has a small leak? Do I still require a new tank? Thanks