O2 Question

[WreckDiver]

Is there any need to have a O2 bottle drained and have fresh O2 put nback in?

I think I have received some bad advise.

I have a LP80 filled with 99.9 (on the tester) that is used for emergancys. Never goes in the water, I will hang a reg on a long hose for someone if they need it but thats it. Sounds like BS to me but does O2 get stale?

[hardcore]

I've also heard the same. I just bought a used LP tank for the same reason. Someone at a LDS told me to drain and refill at least once a year but then they'd get to charge for a new VIP ect. Thanks for asking this bugged, Also does any one know approx. how long 40cf of O2 will last on the surface.

[WreckDiver]

Kyle you would need to provide your SAC rate for the how long question.

[Belzelbub]

What I think you are getting is well-intentioned, but mis-informed advice. If there were some contaminants in the tank, the O2 could react with the contaminants, and leave you with a different mix. Then, when you are expecting 100%, it may be considerably less.

The situation I heard of involved an air tank, that had water (IIRC) unintentionally introduced, was filled and left to sit. By the time the next dive occurred, the PO2 had dropped below that necessary to sustain life.

If you have the O2 analyzed periodically, you would know if that has happened.

[WreckDiver]

Makes sense. What would the by product be IF the O2 is being consumed?

[hardcore]

Kyle you would need to provide your SAC rate for the how long question.

I don't know my SAC rate. Like you I have the O2 for emergency only and If I had to use it on myself or someone I'd like to have an Idea how long it would last.

[bgbill]

when we take our bulk cylinders not dive cylinders to get filled with o2 at crumptons, tri tech or any other gas supplier, an ABO cylinder will be vacuumed 2 times, this is to insure that the cylinder does not have any contaminents in it.

All o2 whether it is industrial, ABO, or medical, it all comes from the same bulk tank.

As far as dumping your cylinder, I don't see the benefit.

How old is the o2 that is in it?

How much is in it?

o2 does not go bad, if there is any contaminents in the cylinder, it can possibly cause the o2 to go bad.

[WreckDiver]

Bret its less than a year old, Its a full PST LP80 & the Cylinder was O2 cleaned by my LDS that I trust - it is not his advise (actually haven't talked with him yet) The guy is pretty particular about what he does and does a good job. So I am quite sure the tank is clean -no rust- because I asked him to make sure that is was even free of flash rust.

Pretty sure he buys bulk avation O2.

[bgbill]

I wouldn't worry about it, there is no reason to drain it.

[Surface Tension]

The by product would be rust, at least in the case I heard of, in which water got in a steel tank and corroded it, utilizing the O2 for the corrosion. Rust is Fe2O3.

[Belzelbub]

Makes sense. What would the by product be IF the O2 is being consumed?

That would depend on what was in the contaminant, it could be a number of different things. If you find that your O2 percentage is dropping, it's probably time to get the tank cleaned.