Is my approach to diving with Nitrox logical?

[MaxBottomtime]

It's all well and good in theory, but the incident rate for DCS has not changed since nitrox became readily available for the dive community. Limiting your depth and total bottom time each day and a slow ascent profile has been shown to be safe no matter what gas you breathe. I use nitrox for the benefit of longer allowable NDLs. I got tired of having to leave the bottom before my buddies just to make deco stops.

 

[scubaozy]

Yes the course I took does include exposure. But I am talking about pulmonary toxicity. not CNS. This specific course was very vague about pulmonary.

Ok understood, at least DSAT table is indifferent whether it is CNS or pul. tox. The latter is usually less of a concern, it is not permanent and you need often much longer exposure and %.

 

[Nitrox_DiverNY]

A buddy of mine does what you do and tries to get the optimal gas for each dive. His nearest dive shop doesn't bank Nitrox, so it's a partial pressure fill regardless, and the only extra hassle is figuring out exactly what percentage he wants based on what dive profile he plans to do next. He's also a little skittish since getting bent while diving the oil rigs a little over a year ago.

I was his buddy on that dive where he got bent; I did not. (The experience still rattled me enough to get me to switch to Nitrox, just not enough to try to get more than 32% on shallow dives.) My local shop banks 32%, and my tanks are not O2 clean, so I just get that. Part of the reason I didn't dive Nitrox much before the DCS incident was that it felt simpler to just always have the same stuff in my tank. I could get it filled whenever it was empty without needing to know what I was going to be doing next. I still operate like that, but I just always get 32% now instead of air. I feel I have enough stuff to keep track of without making things more complicated. But that's just me, not a statement on how I feel others ought to be.

glad your buddy is ok, thanks for sharing

 

[Nitrox_DiverNY]

When I dive at home, I dive best mix as my favorite local shop blends. $12/tank for a cave filled custom mix is YAY! At destinations like Cozumel, Roatan, FL Keys, etc finding shops that will mix for you is either not possible or ridiculously expensive. Therefore when I travel, I just dive whatever nitrox is being banked. In the Keys it tends to be 30%. In Cozumel and Roatan it was 32%. Supposedly some shops bank 36% but I haven't seen one yet.

So, if you've got a blending shop available then do what you like. I think you'll find they're not extremely common in "destination" locations.

Or, take a tech class or two. Buy a couple bottles of oxygen, and mix your own.

There is one fairly good reason to NOT dive best mix. That is, captains don't always go where they planned on going for a variety of reasons. If you've got 40% in your tank and the captain ends up going to a site that's too deep, you're either going to have to borrow a tank of air (if the boat has extra tanks) or sit out a dive or two. That said, I like the bigger boats and they usually stick to shallow sites (under 60') so it's not likely to be an issue on such boats. It's always good to have a conversation with the teenager booking your dive in advance, and then another one with the captain before you leave the dock just in case.

great points, thanks for sharing your experience!

 

[Nitrox_DiverNY]

Ok understood, at least DSAT table is indifferent whether it is CNS or pul. tox. The latter is usually less of a concern, it is not permanent and you need often much longer exposure and %.

im going to have to look deeper into what PADI provides for either form of toxicity, because both seemed rather lacking on their web course. So pulmonary toe would be related more to many repetitive dives on a rich mix?

 

[Nitrox_DiverNY]

It's all well and good in theory, but the incident rate for DCS has not changed since nitrox became readily available for the dive community. Limiting your depth and total bottom time each day and a slow ascent profile has been shown to be safe no matter what gas you breathe. I use nitrox for the benefit of longer allowable NDLs. I got tired of having to leave the bottom before my buddies just to make deco stops.

very interesting. You would think that the rates would change even if it were by a small amount. it would be interesting to see a large sample size study over many years of diving nitrox on air tables. Thanks

 

[tarponchik]

As I've stated on SB several times already, I do believe in oxygen toxicity. Thus, I dive Nitrox only to increase NDL.

 

[Manatee Diver]

thanks for sharing, how does one determine the gradient factor? do only some computers track it?

Shearwater reports it, others might.

 

[rx7diver]

... I do believe in oxygen toxicity. Thus, I dive Nitrox only to increase NDL.

Not sure the point you are hoping to make. Please explain.

rx7diver

 

[Celt]

What benefit are you getting with nitrox over air at 40 feet. There's no point unless there's a benefit. I'll bring the mix all the way to 50% if there's a benefit.