Does Nitrox kill brain cells?

[Cave Bum]

In reading through the posts in another forum, I was struck by something (fortunately it wasn't a dive boat...).

The thread had gotten a bit off topic and someone posted:

100% O2 at 25-ft, baby!!!

I came back and pointed out the MOD formula, which I use as an avatar, and said that should be 20 feet. The answer I got back surprised me, it was:

I was just making a funny. I'm not certified and trained to do anything but regular rec Nitrox.

The MOD calculation doesn't change, whether you're calculating for 32% or for 100%.

Now, maybe I'm a purest, but when I teach the basic Nitrox class the things I have the student do repetitively, several times through the course of the class, so that they won't forget, is calculate their MOD and analyze tanks. That's the main thing folks are going to do when using Nitrox out in the world.

My question is how many of you Nitrox divers were taught the formula when you were trained and how many still remember it and use it and why or why not.

I'm interested in your opinions. Thanks!

 

[sam1]

Was taught it, and remember it (actually I don't "remember" it but I can derive it!) and have "memorized" the MOD for 32% and 36% (@ 1.4 PPO2)

 

[James Bond boat entry]

I use this for metric

(PP02@depth / PP02 of mix) - 1 *10 = MOD

EAN 32% 1.4 PP02:

(1.4 / .32) - 1 * 10 = 33.75 meters * 3.3 = 111.375 feet

 

[DA Aquamaster]

I don't memorize forumlas as memories of that type pof thing tend to be perishable if you do not use them on a regular basis. Instead I focus on learning the underlying concepts as they are much more persistent in long term memory and if you have the concepts, you can derive the formula when you need it.

Even having a student repeatedly use a formula ad nauseum will not boost retention 6-12 months later if they do not use it on a regular basis.

 

[Teamcasa]

My question is how many of you Nitrox divers were taught the formula when you were trained and how many still remember it and use it and why or why not.

I'm interested in your opinions. Thanks!

Practically speaking, I would think that the vast majority of recreational divers certified to dive Nitrox, simply test (or rely on the shop's testing) their fill to determine the O2 mix then program that number into their computers and trust the MOD it displays.

Should they know the formulas? Sure, but if you consider that most recreational divers rarely dive sites that are deeper than the MOD would permit and almost never hit a NDL, I doubt many ever manually calculate the mix to determine the MOD.

 

[Cave Bum]

Practically speaking, I would think that the vast majority of recreational divers certified to dive Nitrox, simply test (or rely on the shop's testing) their fill to determine the O2 mix then program that number into their computers and trust the MOD it displays.

In other parts of the world, do they teach displaying the O2% and the MOD on the tank with duct tape or a pre-printed label?

I know that's in the training strandards but I also know that I've never seen that done on the live-aboards I dove in the Bahamas. I usually see even recreational divers here in North Florida do that but it might be just because they see the tech divers doing it... I'm not sure.

That's the main reason I see for the MOD calculation, to make your label for the tank and to fill out the log in the fill station. Do other parts of the world have you do that?

 

[elan]

I don't memorize forumlas as memories of that type pof thing tend to be perishable if you do not use them on a regular basis. Instead I focus on learning the underlying concepts as they are much more persistent in long term memory and if you have the concepts, you can derive the formula when you need it.

Even having a student repeatedly use a formula ad nauseum will not boost retention 6-12 months later if they do not use it on a regular basis.

Yes pretty much the same here , I do not remember all those 33ft times bla bla, Instead I memorize how to calculate pressure at any depth and then how to get opp at any depth and thus how to get depth at any opp, works the best for me and I can always catch a mistake in calculation doing cross verification.

 

[SkipperJohn]

Practically speaking, I would think that the vast majority of recreational divers certified to dive Nitrox, simply test (or rely on the shop's testing) their fill to determine the O2 mix then program that number into their computers and trust the MOD it displays.

Should they know the formulas? Sure, but if you consider that most recreational divers rarely dive sites that are deeper than the MOD would permit and almost never hit a NDL, I doubt many ever manually calculate the mix to determine the MOD.

I signed up for the course just this weekend and just finished the book. This is what PADI advocates. They show and teach the formula, but emphasize the ease and accuracy of using a Nitrox computer.

 

[Blackwood]

opp

Yah you know me.

This is what PADI advocates. They show and teach the formula, but emphasize the ease and accuracy of using a Nitrox computer.

Makes me suspect that they hold a low opinion of their customer base.

 

[Teamcasa]

In other parts of the world, do they teach displaying the O2% and the MOD on the tank with duct tape or a pre-printed label?

I know that's in the training strandards but I also know that I've never seen that done on the live-aboards I dove in the Bahamas. I usually see even recreational divers here in North Florida do that but it might be just because they see the tech divers doing it... I'm not sure.

That's the main reason I see for the MOD calculation, to make the your label for the tank and to fill out the log in the fill station. Do other parts of the world have you do that?

The main reason for doing the MOD calculation is to let the diver know what is their maximum depth is. The only reason I can see for making a tank label is if you are not going to use that tank right away.

For me, I test the mix, set my computer and go diving. If my tank is refilled with Nitrox and I'm not going to dive it right away, I tag the tank to remind me to test it again before I dive it.