What they don't teach you in Nitrox class...

[RDP]

I believe that discrepancy was warning that his own post was about to be off topic.

I see. I thought he was stating the poster's concept was off.

 

[Spratman]

This is the next course that I want to take. However, I want to take a reputable class. I think this is a bit more difficult to discern a competent instructor, because it's not so much about diving as it is making sure you have the right calculations and mix.

The shop I use is SSI and they offer the course. However, they also offer the IANTD course, but have no one to teach it. Not trying to start any wars, but in this case, I'm a techie and detail oriented. So I want to make sure that I not only understand it theoretically, but can do it practically as well. Might want to take the blender cert as well....

 

[CIBDiving]

No, but you could end up dead because of it. High PP02's should never be taken lightly.

Then do you check your air to see if somebody screwed up and put nitrox in instead?
If you're going to be anal retentive at least be consistant.

 

[JimC]

Then do you check your air to see if somebody screwed up and put nitrox in instead?
If you're going to be anal retentive at least be consistant.

Actualy I do. Twice.

Not that I dive air anymore.

 

[Soggy]

3) It is MUCH better to set the CAL on your analyzer on an air tank rather than ambient.

I have to disagree with you there.

First of all, how do you know what you have in the tank is air and is actually at 20.9%? I know for darn sure that the air I'm sitting at my desk breathing is pretty close to 20.9%. Did you analyze *it* first? +/- 1% isn't going to hurt you unless you are planning your dive right at the limits (you shouldn't be doing that anyhow). Even on the most humid days, I never find I'm more than .4% different from calibrating to dry, tank air, vs ambient air. .4% is close enough.

You *could* calibrate to ambient, then recalibrate to what you believe to be tank air, if you really feel the need to be that accurate, but trusting that what's in the tank is air a nice recipe for disaster.

 

[douglasville diver]

Having Just 5 Dives On Nitrox And 4 Of Them With Mixes Of More Than My Request [ask For 32 Got 35 In One Tank 37 In The Other] [36 & 38 The Second Day] Glad I Invested In My Own Analizer So I Could Re-set My Dive Plan I Was Trained +/- 1%

 

[StSomewhere]

Then do you check your air to see if somebody screwed up and put nitrox in instead?
If you're going to be anal retentive at least be consistant.

I still think it makes more sense to mark air tanks with a big "AIR" sticker and tell openwater divers to only use those, vs. the current method.

 

[my1ocean]

I'm learning a lot here. Never would've guessed that shops opperate with such lax abandon. Here in the Keys, as you can imagine, there's quite a bit of copetition. If a shop gives you 38% when you ask for 32%, they usually don't last long. Where I work we don't let tanks go out more than .5% off.

First of all, how do you know what you have in the tank is air and is actually at 20.9%? I know for darn sure that the air I'm sitting at my desk breathing is pretty close to 20.9%

That's silly. If you fill and air tank with ambient air, how can it be any different from ambient? Unless you're very suspicious of your air system and then I wouldn't want air or nitrox from that system.

 

[Soggy]

That's silly. If you fill and air tank with ambient air, how can it be any different from ambient? Unless you're very suspicious of your air system and then I wouldn't want air or nitrox from that system.

How do *you* know what's in that "air" tank? How do *you* know that it didn't have something else other than air in it prior to being topped with air?

Unless I know how the compressor system works, and physically watch the calibration tank being filled, and know that there was air in it prior to it being filled, then it is just as much of an unknown quantity as the tank you are trying to analyze.

What I do know is that I am breathing air right now, and that humidity only affects the calibration of an O2 analyzer by a fraction of a percent (and even that can be compensated for).

Keep in mind, lazy analysis techniques can get you *killed*. O2 is waaaaay worse than N2 for you underwater. Unless you have had control over a tank from the time it was analyzed to the time it was topped off with air, you do not know what is in it. Trusting a dive shop to not make mistakes could end up being the biggest mistake of your life.

 

[Jason B]

Soggy, when using the air around you to calibrate, do you compensate for the fact that the flow rate on the sensor is not the same as it will be when connected to a tank or do you calibrate it fo 20.9 regardless.
I know that with my meter this factor needs to be compensated for or else your reading will be off by close to 3%.