Diving shallow on Nitrox.

[Nikole]

OK, so I totally get the whole benefit of using nitrox, to increase your NDL. When diving on regular air at 20 feet, you'll run out of air before you run out of time.

When diving 20ft on Nitrox, you'll still run out of sir before you run out of time. So, my question is, why would someone still choose to dive nitrox at 20ft?

I've been on a few beach and shallow spring dives over the summer and have seen this. Just asking!

 

[Lorenzoid]

The only reason I can think of is that the person already had a tank of Nitrox available. If all I have on hand is a tank of Nitrox, I will use it. Some people prefer to, if possible, do ALL their dives on 32% because they like the idea of standardization.

I would also add that a few people will claim Nitrox makes them feel better. The jury is still out on whether that is "placebo effect" or real.

 

[Nikole]

The only reason I can think of is that the person already had a tank of Nitrox available. If all I have on hand is a tank of Nitrox, I will use it. Some people prefer to, if possible, do ALL their dives on 32% because they like the idea of standardization.

I would also add that a few people will claim Nitrox makes them feel better. The jury is still out on whether that is "placebo effect" or real.

Yes I have heard that nitrox makes people feel better, and I've also heard that some can't feel the difference. I've just gotten my. Nitrox cert and have not tried it out yet, but if I was to do nitrox at 20 ft it would be just to try it out. Since I'm still open water especially

 

[_Ralph]

A dive to 20ft? Hmmm, anything between 18/45 and 100% is what I'd dive*

*18/45, well if I only have 40bar left in my doubles from a previous dive, might as well use that gas as I can't get to 200ft with that amount remaining, might as well just breath it on shallow stuff.

OR

I'm on 100% to finish up a long dive on something else.


If I'm knowingly filling tanks for a 20ft dive, air is just fine by me (A 32% or helium please diver)

_R

 

[Lorenzoid]

It also just occurred to me that if you're basing this only on an observation of people using tanks with those yellow and green Nitrox labels, you don't know what's in those tanks. For all you know, someone topped off their Nitrox tank with "21% Nitrox" (that is, air).

 

[CuzzA]

And I'm certainly not going to pay extra for o2 for a 20' dive.

 

[2airishuman]

I've been on a few beach and shallow spring dives over the summer and have seen this. Just asking!

At 20' the only reason would involve gas logistics of one kind or another.

As posted upthread, there might be a situation where the available cylinders of the desired size already have 32% in them. Or a diver might be reluctant to alternate fills between air and 32% because of the need to purge or just the possibility of a shallow dive being canceled in favor of a deeper one. Or when filling cylinders at home there may be a situation where 32% is banked using a stick and the cost savings of an air fill are negligible.

I dive air, but I usually have my cylinders filled after a dive, not before, then I store them full.

 

[kelemvor]

I would also add that a few people will claim Nitrox makes them feel better. The jury is still out on whether that is "placebo effect" or real.

I'm one of them. I can't tell you if it's "real" or "placebo". When a dive trip costs 80ish dollars plus gas plus food for a dive day, the $2 extra I pay for a tank of nitrox at my LDS is totally not significant. I do believe I feel less tired after diving on nitrox, even at shallow depths. I can't quantify it better than that, and given the miniscule extra cost, I really don't care too much to look into it.

I'll only dive air if I'm somewhere like key largo where they have the bizarre practice of vastly more (by the cuft for example) or if I just can't get it at all.

 

[tridacna]

A dive to 20ft? Hmmm, anything between 18/45 and 100% is what I'd dive*

*18/45, well if I only have 40bar left in my doubles from a previous dive, might as well use that gas as I can't get to 200ft with that amount remaining, might as well just breath it on shallow stuff.

OR

I'm on 100% to finish up a long dive on something else.


If I'm knowingly filling tanks for a 20ft dive, air is just fine by me (A 32% or helium please diver)

_R

Ralph - How many divers asking this kind of question IN THIS SECTION know what 18/45 is? Just saying...

 

[Caveeagle]

Some dive shops (near me) charge you a flat rate to fill an 'air' tank of $5. But for banked '32%', they calculate starting/ending pressure so your really only paying for the actual fill. In many cases, I am paying less for a top-off of 32% than a fill of 'air'.

I own my own tanks, so as long as I am diving 110' or less, it will be on ~32%.

As far as benefits... I used to get after dive headaches about 1/2 of the time (not aggressive dives). Since I started diving EAN, this is a very rare occurrence. I know that's not a scientific study, but it has been my experience. Keep in mind, I am not pushing my NDL on every dive so its surely not an apples to apples comparison.