Nitrox cylinder to use for air?

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MrsNic

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Messages
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Location
Chester, UK
# of dives
25 - 49
hi :)
i was wondering if someone could help please?
I have bought a second hand cylinder and it is labeled up as Nitrox. Do I simply drain it and fill it with air (and remove sticker)? Or is there something 'special' I need to do?

thanks
 
If you can't analyse the content, it's best to drain it.
No need to remove the sticker...
 
Simple as that ? :) thank you. And just drain it via a reg/dry sit hose etc?
 
Assuming that the VIP is still good, I would just drain down to 300 psi and then fill with air. 300 psi of any O2 will not matter and best not to run a tank dry especially if there is a wait before filling.
 
Simple as that ? :) thank you. And just drain it via a reg/dry sit hose etc?

Just open the tank valve - not all the way all at once - you do not need a hose to drain a tank. If you open too fast it will make a lot of noise and it will get cold with condensation if you are doing it indoors.
 
300 psi of any O2 will not matter and best not to run a tank dry especially if there is a wait before filling.

Unless its pure O2... In which case you would end up with 28% nitrox for a 3000psi fill. Still should make no real difference in recreational depths, but I am anal retentive about knowing my mix/MOD.
 
As said, no need to remove the labels. Those just indicate that the tank is O2 cleaned. Provided the dive shop fills with O2 compatible air (most do), then filling with regular air won't compromise the O2 compatibility.

If it were me, I'd take the tank as is to my LDS, and have it analyzed if the VIP sticker is current. If it was something I was comfortable using for the depths I usually dive, I'd use it. I normally dive with EAN. If you don't, and it shows other than plain air, you could have them drain & fill with whatever you normally dive.

If it's out of VIP, I'd probably dump the gas, and take it to my LDS for VIP & refill.
 
Yes, don't store it empty, but maybe best to empty it entirely before refilling. Also, I have come across some shops that don't fill empty cylinders, as they say that water may have gotten in and thus they require a new Visual Inspection (and this answers your question).
So maybe empty the last bit at the shop, if you think they can bi like that.

As for emptying, just open it, but not much, trying to avoid a large temperature drop and condensation (and noise!).
 

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