Nitrox - Is it "worth it"?

[Bigbella]

For me, it was always six of one, half dozen of the other. We typically use air for work; and nitrox only when we're certain of maximum depth; number of repetitive dives; and work involved.

I started with EAN in the early nineties, when it first became popular for sport, with all the talk of greater bottom times and, supposedly, lesser fatigue. In all of the ensuing years, I have never noticed one whit of difference, in that latter regard, from air . . .

 

[Angelo Farina]

My personal opinions here...
When I became an instructor, back in 1978, there was no Nitrox, but it was common to make the deco with pure oxygen for shortening the deco time.
At that time the safe limit for Oxygen was 10m, so we did hang oxygen tanks at 9m, for the first of the three deco stops.
Normal dives were always around 50m depth, but often it was 58-60 or even 65. In air, of course, and with a 10+10 liters twin cylinders (plus sometimes a 3-4 l pony, for safety).
At that time, and with those diving profiles, Nitrox was substantially useless, and in fact no one was using it for recreational diving (please note that, at that time, 50m with multistage deco in air was still considered fully recreational, and tec diving was BELOW 50m and with pure oxygen deco).
In more recent years, becoming older, and diving mostly with our sons, I and my wife got rid of those heavy twin cylinders, reduced the depth to 30m maximum, avoiding deco as hell.
With such low-grade diving profiles, Nitrox becomes much more interesting, as it allows longer bottom time.
I do not give a penny to reduced time between dives, as I never made more than two per day, and in 90% of the cases just one. I prefer to spend the rest of the day going around with our zodiac, bathing in some small remote beach which can be reached only by the sea, or playing other aquatic sports such as water ski or underwater wing.
We have also some Golden Retrievers, which of course love being on the zodiac, and swimming with us. A much better family day, than making multiple dives.
However, when the sons were younger, the depth was even smaller around 10-12 meters. At that point, Nitrox is again useless, as air is not limiting the bottom time, as cold becomes the limiting factor (particular with children, they get cold very easily).
So, looking at the wide panorama of recreational diving, I see Nitrox very useful only for a narrow segment, that is medium-depth (20-30m), warm water (so cold is not the limiting factor) and NDL. It does not allow to go much deeper than 30m, so it is useless for the typical diving which we were used to do when young (deep and with some deco). And it is also useless for very shallow depths.
Then of course it can be useful for tec diving with multiple cylinders having different mixtures, but that is way beyond my capabilities and propensity to risk and complexity...

 

[BlueTrin]

As the OP on this, just wanted to update anyone who cares....We're now Nitrox certified and headed to Bonaire in 18 days! Ironically, in the SSI course material overview it literally reads, "It's worth it!" Got a chuckle out of that! LOL! Merry Christmas!

Nitrox Class Shot

• DiveProKoko
• Dec 23, 2019

Congrats hope you had fun

 

[1atm]

The only thing you need to really be aware of that is different from air is your maximum depth. On air you can go to 187 ft depth. On Nitrox ...

I would beg to disagree on this. Yes, with air the pO2 and thus risk of oxygen toxicity checks out ok. But that doesn't mean that air is a safe breathing gas under all circumstances at this depth. Gas density, risk of hypercapnia and narcosis are significantly higher than other gases. Some will disagree, but I on my part will absolutely not dive to 187ft on air. If you ask me, a safe depth on air is somewhere between 90 and 120 ft in great conditions, and may be significantly less in challenging conditions on a working dive.

 

[Bigbella]

I would beg to disagree on this. Yes, with air the pO2 and thus risk of oxygen toxicity checks out ok. But that doesn't mean that air is a safe breathing gas under all circumstances at this depth. Gas density, risk of hypercapnia and narcosis are significantly higher than other gases. Some will disagree, but I on my part will absolutely not dive to 187ft on air. If you ask me, a safe depth on air is somewhere between 90 and 120 ft in great conditions, and may be significantly less in challenging conditions on a working dive.

We did a number of dives, back in the nineties, on air, below 60 meters, on several occasions. The decompression dives were well-planned; there were no unpleasant incidents; though I probably wouldn't repeat them now, being some twenty-plus years older . . .

 

[Angelo Farina]

We did a number of dives, back in the nineties, on air, below 60 meters, on several occasions. The decompression dives were well-planned; there were no unpleasant incidents; though I probably wouldn't repeat them now, being some twenty-plus years older . . .

Exactly my very same experience. Air is safe for rec diving up to 50m, and for moderate tec diving up to, say, 65m. Respecting times and tables!
Of course there are better options (normoxic trimix OC, rebreathers, etc.), but they come at a cost and with added complexity. Then everyone has to evaluate the tradeoffs of each choice...
In any case, I would never use Nitrox for anything deeper than 30 meters.
So, coming to the OP question, yes, Nitrox can provide significant advantages and no drawbacks for those medium-depth dives where NDL is the limiting factor to bottom time.
In all other cases, air comes back as the simplest choice (although not necessarily the best one).

 

[DeepSeaExplorer]

I would beg to disagree on this. Yes, with air the pO2 and thus risk of oxygen toxicity checks out ok. But that doesn't mean that air is a safe breathing gas under all circumstances at this depth. Gas density, risk of hypercapnia and narcosis are significantly higher than other gases. Some will disagree, but I on my part will absolutely not dive to 187ft on air. If you ask me, a safe depth on air is somewhere between 90 and 120 ft in great conditions, and may be significantly less in challenging conditions on a working dive.

I’ve been to 180 on air back in the day. I’ve also been to 180 (and beyond ) on Trimix. After experiencing the difference, I will never do 180 on air again.

In fact, I did a couple 180 dives on 21/35 and found that wasn’t quite enough Helium and started using 18/45 in that range instead. (There is a nice wreck in the Keys at exactly 180.) 150 is my max on air now.

 

[Storker]

We did a number of dives, back in the nineties, on air, below 60 meters, on several occasions.

And how much do you remember from those dives?

60 meters is >1.6 bar pPO2, above currently recommended max pPO2 for deco and significantly above currently recommended max pPO2 for the working phase of a dive. Just throwing out that tidbit of information. Not to mention the effect of >7 barA on gas density and the ability to vent CO2.

 

[Angelo Farina]

And how much do you remember from those dives?

I remember some very nice "nitrogen trips", aka narcosis...
Not really dangerous, the same as 1-2 liters of beer, more or less.
I also remember of a full blackout at Isola di Montecristo, in March 1977. Probably oxygen toxicity, it was well below 65 meters... That was dangerous, as I did inflate my hand-made buoyancy compensator. Luckily I managed to stop the ascent around 30m.
Never gone again so deep, after that experience I set my own limit to 60 meters.

 

[DiveProKoko]

On EAN 32, the PPO2 is 1.4 at 111 feet. In other words, that's the maximum. It's unlikely you will remain at the maximum depth and thus the maximum PPO2 for the entire duration of each dive. Especially on a place like Bonaire, you might start out at a mere 60-80 feet and then lazily wind your way up the slope to the shore, so diving the kind of schedule the OP mentioned in post #144 won't raise any concerns about oxygen exposure. As has been discussed in a few threads, oxygen exposure may be something to watch out for if doing some aggressive diving on, say, EAN 36. But generally, it's a non-issue for us lazy rec divers, especially in a place like Bonaire where there's plenty of good stuff fairly shallow. Which is why being able to spend more time there, thanks to Nitrox, is a good thing.

I like this comment even better now that I'm Nitrox certified and understand what the hell it means! Haha! And I agree! Thanks!