To Nitrox or not to nitrox ,Why and how ?

[doctormike]

Nitrox reduces the percentage of nitrogen in a given mix at a given depth.

No. The percentage remains the same.

Regardless of "given depth".

Actually, I think that you may be misinterpreting waterpirate's statement. Although the term "nitrox" is inexact (it could technically refer to any mix - hypoxic, normoxic or hyperoxic), I assume that he is using it to refer to mixes with more than 21% O2 (i.e EAN, or enriched air nitrox).

I believe that he was saying that it reduces the percentage of nitrogen as compared to air. "Reduces" is probably not the best way of phrasing that, though - you could say that EAN has less nitrogen per unit volume than air, but the concept is the same. For example, EAN 32 has 68% nitrogen by volume, as opposed to the 79% nitrogen in air. This is true at the surface or at any given ambient pressure, according to Dalton's law of partial pressure (each gas compresses equally for all practical purposes).

 

[Splitlip]

On our local ops, the diver who goes OOA does thumb the dive...for himself. I hit my NDL on air long before 1000 psi on repetitive dives.
Nitrox is essential for me. Been using it for more than 10 years and I can do the math. Did not do the class on line and learned it without a computer. Can still calculate EAD's, but dive with 2 computers these days so am rusty.

And Nitrox does make me feel better, even if I max out my bottom time. An air fill is about 5 bucks. I pay ~ 10.00 for nitrox. Worth every penny.

 

[Tigerman]

Personally, if it did not cost twice as much, I would dive nitrox all the time, even for my two dive days of quarry diving. I think that I just feel better afterward. But I am too cheap.

When I am vacation diving, usually a week of four dive days, I spend the extra to use nitrox.

As long as you dive within the recommended limits for the mix, you stand less chance of problems with excess nitrogen and can reduce the interval between dives. I think it is almost required before a trip to Bonaire or Roatan where you can easily get four or more dives a day.

My (relatively) LDS is getting a new membrane system over the summer.. And will charge the same for nitrox as they now are for air. Guess what Ill be putting in MY tanks

I always use nitrox on my dive vacations and quite often as if it was regular air (With the exception of MOD) so I just get even more safety margins than computers/tables already provide. Not a bad thing if youre diving every day for a week or more.

 

[k ellis]

I always thought that the bottom time and NDL are actually correlated Did you mean to say SI time ?

LOL yes I did. Teach me to sit in a parking lot and type on a computer. Should have been working anyway

Yes it lengthens the NDL and shortens the SI. Thank you for pointing that out

 

[Tigerman]

LOL yes I did. Teach me to sit in a parking lot and type on a computer. Should have been working anyway

Yes it lengthens the NDL and shortens the SI. Thank you for pointing that out

Yeah, thats what you get for being PARKED while typing! Learn to do it while driving

 

[AnotherNewguy]

I've only dove Nitrox once (one trip, two dives) but the difference for me was amazing. I didn't really know that there would be a difference as I didn't feel terrible after air dives. I had a headache and was pretty worn out but I could manage. After my Nitrox dive, I had no headache at all and if put on a scale of 1(worst)-10(best), I probably felt like an 8 after Nitrox and a 4 after air.

 

[Tigerman]

I feel pretty much no difference wether I dive air or nitrox even on the same profiles. I definetly wont claim I could pick wich tank is air and wich is nitrox if I did a blind test on them (Which btw would be against all guidelines with regards to using mixed gases to do)

 

[Frosty]

On our local ops, the diver who goes OOA does thumb the dive...for himself.

My apologies. I meant low not out

 

[Dr Wu]

Actually, I think that you may be misinterpreting waterpirate's statement...

Ok, let's take a look:

Nitrox reduces the percentage of nitrogen in a given mix at a given depth.

Yeah.. no.

The percentage does not change with depth.

I'm gonna stick with "wrong".

 

[Deefstes]

OK --Im liking the sound of longer bottom time especially at some of our local dives. I suspect its a waste of time for vacation diving given the first diver in the group that signals they are low on air thumbs the dive for the group anyway

Just bear in mind also that Nitrox will not extend your bottom time beyond what your ordinary gas consumption would allow. In other words, whether you're diving air or Nitrox, your gas consumption will still be the same and your bottom time will not be extended just because you're diving Nitrox. So, if your dive times are usually dictated by the amount of air you use, you might not benefit from Nitrox at all - other than having shorter surface interval requirements.
I know, it might sound stupid to point this out but I did encounter a guy some time back who didn't understand this and thought that Nitrox would help him get by on fewer breaths (because it has more oxygen per breath).