I just had my co2 tank refilled at bioplast when I observed that no more bubbles were coming out and the gauge reading was 500psi.

After refilling and setting it up, I was surprised to see that the gauge reading is 1500psi.

The past few times I refilled the psi stayed at about 1000.

Is the pressure gauge faulty? Besides this it works fine though. Although the needle valve is acting up a bit too.