air pressure

I bought a brand new Sherwood Vision. I've been diving with it daily for the last eight days with 20 dives. As I was doing my gas check for the 21st dive, the air pressure reading read 10 bar. Perhaps the tank didn't get a refill, so I switched over to another tank. Similar low pressure reading...

Hi all dear advanced divers There is very simple question about cylinder volume and it is : what is the volume of 10 liter cylinder in 200 bar ? Air volume = cylinder volume + pressure = 200 * 10 = 2000 liter But in next they say what is the air volume of 10 liter cylinder in 300 bar and 400...