Nitrox - Is it "worth it"?

[kelemvor]

Whether on a particular dive you want to pay the extra $10 or whatever is up to you

If you're doing local dives with your own tank, it's often cheaper than that. My LDS charges $10 for air fills, $12 for nitrox. So I pay $2 extra per tank. It's a no-brainer.

Costs a little more when i go on a Caribbean vacation, still it's well under $200 for a week of nitrox. When the trip is 2-3k, that's pretty inconsequential.

I have run into one shop that charged by the cubic foot for nitrox. When you find those sort of dive shops, you just avoid them as you would avoid the bubonic plague.


Remember kids, air is for tires - not scuba tanks!

 

[CAPTAIN SINBAD]

And by "worth it" I mean, in your opinion, what type of diving (frequency, etc) is Nitrox a benefit, etc. I've done a little research into this and figured as part of that research I might as well ask for opinions here amongst veteran divers and those who have used Nitrox. My wife and I are going to take our first trip to Bonaire this January. Super excited by the way. We are both experienced divers but have never felt we had the "need" for Nitrox certification since we've mostly done boat dives with charters or on our own and seldom dive deep, preferring longer bottom times.

As soon as we told our local people here we were going to Bonaire, the first thing they said is, "You should get Nitrox certified." They explained, and I found through my research, the benefits of shortened surface interval times and all that, which I understand. But really, my question is this, "How much diving do you need to be doing to NEED the shortened interval times? And to what extent is it worth the cost to certify, etc.?" I guess I'm trying to weigh the realistic amount of diving frequency while we're there with the cost of $300 bucks to get us both certified before we go. Realistically, I see us doing a couple dives before lunch each day, having a surface interval that involves stopping somewhere to eat and taking our time there, then doing one or two in the afternoon (depending on if we feel like hanging out at the pool or not, haha), including a couple of night dives while we're there. We'll be diving for 6 days. I know each person's dive profile and all that factor into the equation, but the sites there are pretty set in relative depth, etc and most people I would guess would have similar profiles for reef/shore diving there. Any thoughts are appreciated. Thank you!

Short answer? Yes! Firstly nitrox certification is a cheap class that involves one single day of classroom. You will learn nitrox theory, how to analyze your tank and MOD etc. It is too cheap, too easy to not have it. Once you have it, I have never seen anyone complain that they have a little more time in the water specially not in Bonaire. More importantly, a lot of people, after breathing a higher oxygen mix, report that they feel more energetic after the dive. Now this shows that these individuals were experiencing mild decompression sickness in the form of soft fatigue while staying within the NDL limits. Decompression is not as exact as our tables and computers tell us and this results in a certain population that feels fatigue after the dive but does not attribute it to DCS. They can tell the difference when they switch to higher oxygen mix.

With all the benefits and the cheap cost associated with it, why not?

 

[Manatee Diver]

I have run into one shop that charged by the cubic foot for nitrox. When you find those sort of dive shops, you just avoid them as you would avoid the bubonic plague.

Most of the places I see do that are in cave country, there you aren't breathing a tank down to 500psi. So for me it might cost less than $10-15 to top off both tanks.

 

[Hoag]

A lot of people have responded stating that if you are hitting your NDL before you are running out of air then NITROX is a good idea, and that is absolutely true, but there is another situation when I think it is a good idea. If you are subject to some of the contributing risk factors for DCS, then NITROX will lower (it will not eliminate, but it will lower) some of the risks. In my case, I am 60years old and overweight. NITROX just seems to make sense for me to use whenever possible.

 

[Outbound]

Wouldn't you have exactly the same issue if both of you are on the same gas, but your insta-buddy has considerably higher gas consumption than you?

Yes. But in this case:
a) I'm still going to figure out a way to switch buddies for the subsequent dive(s), and
b) For me at least, there is a difference between someone who has a naturally higher baseline gas consumption versus someone who decided to go on a dive vacation solo knowing they are going to be buddied up with a stranger and not bothering to get a nitrox cert, especially if it's at a location where nitrox is very popular or the norm. Assuming the person is a relatively competent diver with good buoyancy control, properly weighted, not sculling, etc., then the higher gas consumption is what it is. But everyone has the opportunity to get nitrox certified. If you have the money to go on a dive trip, then you have the money to get your nitrox card.

I'm not saying that this situation pertains to the OP, by the way.

 

[kelemvor]

Someone needs to post a summary. Here's what I see as the benefits:

1. Reduces sub-clinical DCS symptoms (e.g. post-dive fatigue).
2. Increases NDL time.
3. Reduces minimum surface interval. (some operators won't require an hour long SI if you're on nitrox!)
4. Reduces DCS risk.
5. Nitrox stickers (some people like the appearance)

In the drawbacks column:
1. Certification cost
2. Fill cost
3. Tank cleaning cost (if you own tanks and get partial pressure fills)
4. Nitrox stickers (cost and appearance) although they aren't strictly required.
5. Introduces a maximum depth limit aka M.O.D. (actually, safe MOD is already limited with air but with nitrox the limit is shallower than air).
6. O2 analyzer cost (many people decide they want to buy their own instead of using the one that the fill station provides).

You could narrow that drawbacks column to "cost" and "MOD" really.

 

[Outbound]

Someone needs to post a summary. Here's what I see as the benefits:

1. Reduces sub-clinical DCS symptoms (e.g. post-dive fatigue).
2. Increases NDL time.
3. Reduces minimum surface interval. (some operators won't require an hour long SI if you're on nitrox!)
4. Reduces DCS risk.
5. Nitrox stickers (some people like the appearance)

In the drawbacks column:
1. Certification cost
2. Fill cost
3. Tank cleaning cost (if you own tanks and get partial pressure fills)
4. Nitrox stickers (cost and appearance) although they aren't strictly required.
5. Introduces a maximum depth limit aka M.O.D. (actually, safe MOD is already limited with air but with nitrox the limit is shallower than air).
6. O2 analyzer cost (many people decide they want to buy their own instead of using the one that the fill station provides).

You could narrow that drawbacks column to "cost" and "MOD" really.

Can anyone point me in the direction of an actual study that concludes that diving on nitrox reduced fatigue? I've often heard people say this anecdotally, but I would like to see some evidence. I don't find that I'm any more or less fatigued when diving nitrox versus air. As for reducing your DCS risk, that's only if you basically dive as if on air while actually using nitrox (keeping in mind your nitrox MOD of course). If you ride your NDL on nitrox, you have the same DCS risk as if you ride your NDL on air.

As for your drawbacks, I would argue that all of them except #1 have to do with DIVING nitrox, as opposed to being CERTIFIED for nitrox. I'm nitrox certified but generally don't use it when diving locally because it doesn't make sense for my dive profiles and situations. When I'm on a tropical vacation and diving multiple times a day for multiple days, then that's when I bust out my nitrox card and use it. I don't use nitrox in my own tanks at home, so I don't have any of those associated expenses.

 

[svs]

I am nitrox certified and there are many places where it gives benefit but I've been to Bonaire 4 times and never used nitrox. Air worked fine for me, gave more flexibility and I never felt restricted by NDL doing 4-5 dives a day, since you always have an option to move shallow toward the end of the dive.

 

[MaxBottomtime]

There have been three studies, none of them show any real difference. The only way to tell would be a double-blind study involving hundreds, if not thousands of participants. Unless someone wants to foot the bill for that study, it's not going to happen.

#1 is a placebo effect. Many divers read about getting less fatigue on the internet, and by the power of suggestion, believe it themselves despite no clinical evidence.

#4 is technically correct, although there has been no increase nor decrease in the number of DCS cases since nitrox became mainstream. It has been estimated that the number has only dropped by less than one in 10,000. Certainly not enough to claim that nitrox is safer.

 

[Bob DBF]

Because I dive locally, in NorCal, I don't bother with Nitrox because I find no advantage in using it for the two, possibly three, shore dives I would make in a day, or occasionally double that for two days in a row. My target depth is usually not deep enough, long enough, to make a difference.

I did however get a Nitrox cert to use on liveaboards where the number of dives and depth make it advantageous as I like to avoid riding NDL.

Can anyone point me in the direction of an actual study that concludes that diving on nitrox reduced fatigue?

1 is a placebo effect. Many divers read about getting less fatigue on the internet, and by the power of suggestion, believe it themselves despite no clinical evidence.

Because there is a scientific definition of fatigue, it was found that there was no reduction in fatigue. However, one study noted that the subjects felt better after using Nitrox, to the point that a majority predicted accurately when they were on Nitrox. The scientists attributed the "feeling better" to lower decompression stress, but this was just an interesting anomaly because that was not the objective of the study.

Personally, for a couple of dives I see no difference between the gasses, over the course of a three day lobster trip, 16 dives more or less, I feel much better with Nitrox, and will pay the premium. Lower decompression stress makes sense, and I don't care if it's that or less fatigue as long as I feel better. I was not a believer, I was coerced by a buddy to get the cert so we dive the same profiles, the effect was a pleasant supprise.

If the effect of Nitrox is from decompression stress, any diver that stays well away from NDL
would never see the effect since that stress is minimized. The same would be true of those divers that naturally off gas better than others. And of course the placebo effect. I think this is the reason that the anecdotal information is all over the chart.


Bob