windapp
Contributor
Also, mechanical pressure gauges can be wildly inaccurate, especially with use. I've seen old SPGs that were off by 150-psi. A guy ran out of air when his SPG showed 150-psi and I had to feed him my air for a bit. Luckily we were at 30-ft.
Pressure gauges like all other equipment should be checked regularly. I would not dive with an SPG I knew was off by 150 PSI.