divengolf
Contributor
Now here is a really good question. When "checking" out a NITROX cylinder you record the O2 contents and most often the pressure. Yet when you get a cylinder with air neither are done. So how many check the pressure with an air cylinder? Conversely how many check the O2 content for an air cylinder that supposedly contains 21%
My personal policy is to always analyze any tank that I'm diving for CO and, if I'm diving air, I'll analyze for O2 if the filling facility has the ability to fill nitrox. So, in practice, I almost always analyze for both O2 and CO. I rarely dive air any more. I'm especially wary of those who do individual tank partial pressure O2 blending. That's an art that is frequently messed up.