Does gas go bad / expire / go stale in a tank?

[jlayman800]

If somebody hasn't broken in and added or taken out some O2, it will still be the same precentage it was when it was filled. There is no magic. The precent O2 doesn't change.

Particularly with Nitrox, the air mixture in the tank is good for as long as you have it. The air and O2 put in your tank was particularly clean if it came from a qualified Nitrox fill station and the tank was particularly clean because it is a Nitrox tank. I believe you are safe holding it for as long as you want.

Of course I'll check the O2. So how long does anybody think that should be good for? I plan on going to the shop tomorrow to use their analyzer, anybody wanna guess what it'll read??

 

[rescuediver009]

Although the gas does nto expire, I onceserviced a tank that was an AL19 cu ft. It was reserved as a bailout bottle only and it had a 36% mix in it for a year as the guy never used it. Well, when I opened it up there was a nice racing stripe of oxidation on the side it was stored on. Not the end of the world but I would recommend that it be cycled through soon.

 

[KidK9]

Yeah, I had it analyzed at the shop, ot read 32.1%, as I kinda expected. It'll get used this weekend in Ginnie Springs.

 

[pescador775]

Air or Nitrox stored in an aluminum tank can take on a funky smell. This happens over a couple years if the tank has any moisture inside. The O2 level won't vary much, IMO.

Yeah, I had it analyzed at the shop, ot read 32.1%, as I kinda expected. It'll get used this weekend in Ginnie Springs.

 

[matt_unique]

Yeah, I had it analyzed at the shop, ot read 32.1%, as I kinda expected. It'll get used this weekend in Ginnie Springs.

With AL tanks serviced and maintained you should be fine but it's just a good idea to have it reanalyzed and take a breath for a taste test.

--Matt

 

[Orlando Eric]

Now there is a question everyone strides to never ask! If my wife ever comes on here and ask how long air last or EANx tell her only about two weeks! "I have got to dive this weekend honey, my air will go bad and that would be a waste of money!"
BTW condoms only last about two weeks also.. after that they go bad, so we had better use these up tonight...

 

[Texas Diver]

The general opinion from the manufacturers is that compressed medical gas products, including pure O2, do not degrade over time. The only check necessary apart from periodic cylinder structural testing is remaining pressure.

That is my understanding also.

 

[Curt Bowen]

Hey all, bought a new AL80 last year (Luxfer), and wondering how long my 32% Nitrox is good for. It was filled and checked last September - so the air is around 8 months old.

Forever. Just analyze the gas before using it.

 

[GotAir]

In general can air go stale in a scuba tank (Reason)I just bought a guys complete scuba gear collection and it came with 2 tanks and a bunch of other goodies. it looks like the last time he had them filled was 12 yrs ago. i was going to use the air in the tanks before I have them hydroed and filled again.

 

[rab]

I don't think I'd trust a 12 year old fill. AL or not, it just can't be worth the few dollars.

-Rob