Advanced Nitrox

[Joe21]

Im nitrox certified and routinely dive it to 80ft. My question is what will advanced nitrox allow me to do over regular nitrox? Stay down longer?

 

[Kevin Carlisle]

Yes and no. Advanced Nitrox is for use of more than 40% o2 in your mix. This is more for decompression than recreational diving. If you wanted to dive a higher percentage o2 than say EAN32 you really eat up your o2 clock and I could not see where that will help you. If you interested in deep diving and doing planned deco, its a great course.

 

[Blackwood]

Im nitrox certified and routinely dive it to 80ft. My question is what will advanced nitrox allow me to do over regular nitrox? Stay down longer?

Ignoring the standard training paradigms, the only thing you can do which will allow you to stay down longer is to carry more gas (or recycle the gas you breathe).


The most common use for advanced nitrox is to get you out of the water faster; that is to say 'to accelerate decompression'.

Baseless example:

Say you dive to 100 feet for 50 minutes, and your table/computer/software tells you to decompress for 30 minutes on backgas. With an advanced nitrox certification, you have access to gases with high oxygen content, and switching to such a gas may cut that obligation down to 20 minutes, or 15 minutes.

 

[spacemanspiff1974]

Very different class than regular nitrox. This is typically taken with deep air in some sort of tech lite or intro to technical course. Gas planning is involved as is decompression diving. Typically this involves the use of EAN50 where the diver switches to this tank on the way back up from a deeper depth. Diving with doubles may also be part of the course.

 

[ianr33]

Advanced nitrox will ,typically,introduce you to doubles.It will certainly introduce you to decompression diving. At the end of the course you will have a card good for 100% O2 (With TDI at least)
Being able to use 100% oxygen is not much use unless you also do the "Decompression Procedures: " course which allows staged deco using high O2 mixes.

So,Advanced Nitrox will be doubles,limited deco on backgas.Maximum depth 130 feet.
Deco Procedures extends that to longer deco,slung deco tanks and a maximum depth of 150 feet. The two courses are commonly done together.

Advanced Nitrox is a great course for any serious diver who finds himself nudging NDL's on a regular basis.

I did Advanced Nitrox/Deco a few years ago in Cayman. Graduation dive was 150 feet for 30 minutes and unfortunately got me hooked on a very expensive pastime!!

 

[Joe21]

Thanks all. I spearfish alot and theres quite a few 100ft and deper ledges up here, but theres hardly any bottom time especially for spearfishing.

 

[Blackwood]

Thanks all. I spearfish alot and theres quite a few 100ft and deper ledges up here, but theres hardly any bottom time especially for spearfishing.

If you constrain yourself to "NDL" tables/computers (which your question in the QA forum suggests that you intend to do), you're SOL.

Increasing the oxygen content in your mix is going to decrease your available depth range.

Recall the toxicity section from your basic nitrox class. If, for example, you set a maximum PO₂ of 1.6ATM, breathing EAN50 you'd have a floor at 70 feet. More oxygen, less depth.


Does breathing i.e. EAN70 theoretically allow you more time at 100 feet than does EAN32? Sure. From a decompression standpoint, yes, not that you'll likely be able to find decompression tables written for PO₂ levels much beyond 1.6.

 

[Joe21]

Yes I understand but will advaced nitrox allow you to stay down longer on say a 32% mix and swich to a higher percentage of oxygen on the way up without being considered deco.

 

[Jim Lapenta]

No. If you are doing gas switching to accelerate the time you need to spend before surfacing you are still doing an accelerated decompression profile. Gas switching and carrying a mix other than backgas puts your foot into the technical diving world. Not something to play with without training. Staying down on say 32% beyond the NDL's for it you also need to start monitoring your CNS clock, your PP02 levels, and your depths alot closer.

If your profile is correct you state you took nitrox immediately to start doing the 80 ft dives. Did you take an advanced course as well? 80 feet is beyond recommended OW depths. Why would you take nitrox to dive deeper without a good AOW course? As it is no good instructor will allow you to take a tech course like adv nitrox without some deep experience (100-130ft), AOW, an intro to tech of some kind, and at least 100 dives. And you should plan on doubles at least.

 

[Joe21]

As I stated I spearfish so I took the nitrox so I could safely stay down longer. I felt that the AOW course was not necessary and did not replace my own experience. Quite a few of the dives I do are in poor vis with strong currents and I handle them safely. all of the diving I do is within recreational limits and is covered by but not necessarily recommended by an OW cert.