A year ago a dive buddy of mine bought an ex-air force Davey compressor. It works great. We've probably done a couple hundred fills on it so far. So, I've got a 19 cu. ft. aluminum pony bottle. For several months the compressor topped it up to 3000psi, like every other tank. But for some reason I just cannot figure out, the last five times I have tried to fill it it will only take on 2200-2300psi. The compressor has three fill whips and the other two tanks load to 3000psi, but the pony bottle comes up short. This only happens on my pony bottle. I have checked it with multiple pressure gauges, and also double-checked the gauges on other tanks. It is not the gauge. Also, it's not a matter of heating/cooling, since I used to get a full fill in the pony during the summer. The o-ring is fine. Anyone have any idea why this is happening? Could I have some kind of partial obstruction in the pony valve?
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