Why get Nitrox certified?

[beaverdivers]

Have FUN at Sunset house! Do a 21% nitrox dive for me.

 

[MMM]

Since I'll be diving air, we'll see how long my new Mares Puck computer allows me to stay down on each dive.

Mares tend to be one of the more conservative types of computers. If you push your NDL whatsoever on your first dive, it will surely complain on the second. I have never dived in Grand Cayman but for some reason, I'm thinking the typical depths are shallower than here in Cozumel where I ALWAYS dive nitrox for my second tank. And so hence I disagree with theduckguru about not bothering if you are a vacation diver only doing 2x day.

To answer your initial question briefly, a diver on a typical nitrox mix (32 or 36%) following the same profile (time and depth throughout) as a diver on air will take on less nitrogen due to the higher % oxygen in the gas. I don't dive nitrox to reduce the risk of decompression sickness...I breathe it to extend my dive time by altering my NDL. While other divers on the boat are checking their computers and staying higher on the reef, I know that I have lots of NDL time and can use much more of my gas up close and personal with the reef. Since I seldom push the NDL breathing nitrox by virtue of there being other divers in the group on air, I have a secondary result of reducing decompression sickness...but that wasn't my main intent. Unless a lot of the divers on the boat are on nitrox, including the divemaster, in which case then we usually push our NDLs to the degree our various different computers with their different algorithms permit. FWIW, someone once told me there was no point in getting a nitrox cert unless you are coming up against NDL limits and you still have loads of gas left in your cylinder at the end of your dive.

 

[MMM]

If you are the 2 dive a day vacation diver, don't waste your money on nitrox training or diving nitrox.

Why do you say that? I think for anyone who is good ontheir air, it is one of the best certs you can get.

 

[grantwiscour]

Anyway, I'll be sitting in My Bar each day drinking smoothies and eating Indian food and posting on Scuba Board, so will be looking forward to sharing my vacation with my Scuba Board friends.

I look forward to some dive reports and photos of your trip.

 

[redacted]

Yes, the risk of DCS is reduced for the same profile - depth & time if you use an Enriched Air Nitrox ( EAN ) of 32%, for instance, than a nitrox mix of 21% ( air ).

Yes, the risk is the same if you go to the "max" of mix, not that you want to take it to the "max".

Yes, we are approaching the point where nitrox is becoming integrated into Open Water.

Yes, you should dive nitrox on every dive, even if you are just doing one or two dives a day. Ok, if you are going no deeper than 40' then a 21% of nitrox works.

In the old days prior to the 70's, divers were taught that you could not get bent on a one tank dive because they were

using 72 cu. ft. tanks.

Then 80 cu.ft. tanks became the standard and yes you can bend yourself on an 80. ( and yes, you may be able to get " Bent " on a 72 if you really try! )

Yes, you can get DCS even if you have a high workload and can NOT stay down to the limit of mix, 21%.

And you can Oxtox on a 30 - so what is the point. There are some dive where an enriched mix of O2 is smart. There are lots of dive where all it does is make extra $$$ for the nitrox supplier. I only dive nitrox when there is a good reason - Like it is no extra cost and MOD is not a problem for my planned dive.

 

[beaverdivers]

If you figure your cost per minute of bottom time, then EAN nitrox makes sense ( or dollars! ).

 

[TMHeimer]

My take on nitrox--

It does cost more--there was a thread citing $24 a fill. It's not a big factor, but a factor. If you tend to like shorter dives or get cold easily it might not be much of an advantage.

I try to dive what the majority on the boat are diving so it's convenient for all if possible.

I'm usually on the bottom all the time hunting shells. So I like a depth that doesn't approach the ox tox level if possible. You can't go deeper than the bottom.

 

[redacted]

If you figure your cost per minute of bottom time, then EAN nitrox makes sense ( or dollars! ).

If you can safely do the same dive on a tank of air, then the added cost of EAN makes no sense, But it does make $$$ for the provider;.

 

[MMM]

My take on nitrox--

It does cost more--there was a thread citing $24 a fill.

So what was the differential cost between that and air? Here in Cozumel the op I use charges $10 extra for nitrox whether you are using their steel 95s or 120s. I think the typical nitrox cost for an aluminum 80 is about $8 extra. (It was $3-5 extra when I first started diving here...)

 

[boulderjohn]

If Matt can make sense of this dizzying array of advice, more power to him. Here are my thoughts:

If you dive nitrox but follow an air profile, you will be safer, but only to a degree not worth mentioning. The risk of DCS on air tables is extremely remote; using nitrox makes something that is extremely safe marginally safer--not worth it, IMO.

If all your dives can be described as following a DM around in relatively shallow water with other divers, most of whom are on air, and then finishing the dive when the DM says it is time to finish it, then you will get no real benefit--not worth it, IMO.

If you can do dives (enough gas plus the ability to dive to your new limits) with longer bottom times approaching NDLs the way you do with air, then you are not one bit safer than diving on air, but the longer bottom times are the reason for the nitrox--very well worth it, IMO.

And although it is not proven by any scientific means, I am in the group that says you feel better and have less fatigue if you are diving nitrox--very well worth it, IMO.

Unless I am diving very shallow, I will do nitrox on every dive that is not too deep to prohibit it.