How do you make oxygen clean air?

[CAPTAIN SINBAD]

This has been very enlightening for me. I am now thinking about doing a gas blender certification and possibly volunteering in a dive shop on weekends. I think it will be a good way to learn / utilize this info in a supervised environment and also make some friends in the dive industry. Thanks everyone.

 

[divingtactics]

Generally OCA involves putting an additional filter after your banks but before your panel. Mike Casey from Lawrence Factor has written a series of articles which should answer your questions.
http://www.lawrence-factor.com/Library/Nitrox.pdf
The downside of using a personal filter is that it is open to the environment when not under pressure and not in use, this means that the Molecular Sieve (MC) will absorb it's maximum moisture - generally 22% in a couple of days and is virtually useless after that. This means that a personal filter will not remove the moisture content but the Activated Carbon (AC) will still remove some nasties, but is virtually ineffective when the outer layer of the MC shell is covered in compressor oil, which will then work its way to the AC outer shell too rendering it useless.

What I have done is to add a 33-inch tower after my main P0 (P21) filter on my Bauer Oceanus, along with another check valve, pressure maintaining valve (PMV) and Over Pressure Relief Valve (OPV). Then after the 33-inch tower but before the final PMV, I've added my personal inline filter but filled the cartridge with Hopcalite, which will convert CO to CO2.