Nitrox Question

[gcarter]

My son and I will be doing the EAN course in early April. Regular visual inspection sticker is $15/tank, $25 for Nitrox after a $50 O2 clean (I have not done the VIP on the tanks yet this year). Fill cost for air and for premix 32% is the same on fill cards.

Should I get my tanks O2 cleaned and stickered? Assuming I will not be exceeding the depth limits, is there any reason not to use Nitrox regularly? I would assume it would be a benefit, but I do not know what I do not know

TIA

 

[Julian55]

I use Nitrox exclusively now, no reason not to if the cost is the same. Check with your LDS about cleaning etc, they will give you the best advice usually.

 

[kierentec]

if they have premix 32, why do they require your cylinders to be O2 clean?


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[mathauck0814]

You should not need to O2 clean your tanks unless they will come in contact with rich blends o EAN (>40%). If they're banking/premixing and decanting it you shouldn't need it cleaned.

 

[TSandM]

You haven't taken your class yet, but one of the things you will learn is that there are several ways of making Nitrox. One way is to empty the tank, and put in an amount of pure oxygen, and then top that with air. That's called "partial pressure blending". When a shop makes its Nitrox that way, your tanks and valves have to be O2 cleaned, because they will be exposed to oxygen in concentrations above 40%.

If, instead, the shop uses a membrane system, or continuous addition of oxygen, then your tank will never see oxygen concentrations that high, and there is really no need for special cleaning. This is also true if the shop banks 32% and will always be filling your tanks from the bank.

However, some shops, although they bank 32%, may not have large banks, and on heavy diving weekends, may need to do some PP blending. So it's a good idea to talk to your shop about whether they sometimes do this, and whether they require the O2 cleaning. Having your tanks O2 cleaned may also facilitate getting Nitrox fills elsewhere, if you drive to another area to dive. There is no need to have your tanks specially marked for Nitrox, though, either way, although some shops will insist on it.

There is no reason not to dive Nitrox all the time, and many of us do. If you are doing multiple dives on multiple days using the maximum allowed concentration for recreational diving, you may push oxygen toxicity limits, but outside of that peculiar circumstance, in recreational diving, you won't.

 

[altaskier]

My tanks are O2 clean, but I don't get a nitrox fill all the time. Sometimes I know I'm only doing one or two dives in the 30-50 foot range and I don't bother with nitrox at $4/tank more, or sometimes I'm diving deeper than the 32% limit and I'll get a 28% fill. At my local dive shop (and also the one where I used to live) you can either get a nitrox fill or a "O2 clean" air fill, meaning that they use an air compressor that won't compromise the nitrox cleanliness of the tank.

 

[rhwestfall]

TSandM nailed it. If you travel somewhere with your tanks and they only do PPBlending, and your tanks aren't o2 cleaned, you are SOL.....

 

[mathauck0814]

TSandM nailed it. If you travel somewhere with your tanks and they only do PPBlending, and your tanks aren't o2 cleaned, you are SOL.....

By the exact same token, if you travel somewhere with your O2 clean tanks and they don't have oxygen compatible air, you just wasted $50 as you need to re-clean your tanks.

 

[rhwestfall]

By the exact same token, if you travel somewhere with your O2 clean tanks and they don't have oxygen compatible air, you just wasted $50 as you need to re-clean your tanks.

yep, unless they are pumping "ultra pure".... hosed either way....

 

[gcarter]

Thanks for all the responses. The LDS where we will be doing the course is the one I bought my tanks from and who would be doing the VIP and are the shop that I have a mitt full of fill cards for and...

So I guess the answer is (I don't plan on travelling with my tanks) ask them whether I need the O2 clean or just the VIP, and then dive away on Nitox.

Cheers!!