An age-old question: ways to 60m.

[Blackcrusader]

Plenty of opportunities for amazing dives that are perfectly fine to do with Nitrox, and they'll be even longer as they're shallower.

I've been with divers on Nitrox who are at 30m depth head up to 20m and have to end the dive after 30 mins due to using up their gas. It's not longer for everyone just because they stay shallower.

 

[Nick_Radov]

Have we even defined what is "deep air" yet?
Or is that a moving target depending on who you talk to?

It's somewhere in the range of 100 - 130 ft / 30 - 40 m. Pick a number. I would argue for the shallower end of that scale but whatever. If someone is quibbling over precise definitions then they've already lost the plot and obviously aren't interested in learning. It's like arguing over whether the blood alcohol limit for DUI should be 0.08% or 0.10%. Better not to press the limit in the first place.

Someone once told me that people are idiots for breathing air at all, and only 32% is acceptable down to 100' and past that it has to be trimix.
Is that still a rule?

It's more what you'd call "guidelines" than actual rules. Sticking to a single set of standard gases simplifies logistics and dive planning, and reduces the risk of mixing errors. But if you want to use air or some oddball nitrox mix for a short, shallow dive then whatever. No one cares.

Standard Gases: The Simplicity of Everyone Singing the Same Song

Like the military and commercial diving communities before them, Global Underwater Explorers (GUE) uses standardized breathing mixtures for various depth ranges and for decompression. Here British wrecker and instructor evaluator Rich Walker gets lyrical and presents the reasoning behind...

indepthmag.com

 

[Boarderguy]

www.facebook.com/share/r/18yiGJLEMy/

This is the only acceptable time and place for breathing air in the water according to some

 

[NothingClever]

I'm a believer in standard gases. Best mix is entirely impractical, IMO.

I typically really enjoy the InDepth articles but that one above missed the mark for me.

I prefer the explanation from page 151 of Chapter 7 in the book "The Fundamentals of Better Diving".

21/35 is not so egregiously expensive that it's out of question for a long tour around a wreck at 35m or a long DPV cruise along a coral wall. However, I wouldn't draw that gas for a weak or ill-defined objective. I'm not just drawing Trimix to burn it on a random splash. If I'm just doing a MDL dive, I'd just go shallower and burn 32% because it's the most flexible EANx gas around.

 

[Blackcrusader]

The best way to deal with stress is to be prepared. Like having an appropriate gas mix...

If 32% nitrox available I use that for dives to 30m but to 40 - 45m then I'm on that old fashioned 21%.

 

[Blackcrusader]

This is all quite entertaining and it's threads like these that keep the board alive. Great reading material!

Have we even defined what is "deep air" yet?
Or is that a moving target depending on who you talk to?
Someone once told me that people are idiots for breathing air at all, and only 32% is acceptable down to 100' and past that it has to be trimix.
Is that still a rule?

No it has never been a rule. It is a prescribed agenda for some agencies. There are many places that only have 21%. Raja Ampat, Belongas Bay Lombok Indonesia, Fuvamulah Maldives,

Are people going to cancel dive vacations to places that only have 21% I doubt it.

 

[Celt]

Just stop this asinine, immature, childish shiiit. Enough already.

Look I’m sorry about you’re loss but I’m going to give as good as I get, read my advice to the OP, I said if you’re not comfortable at 50m on air you’ll need to pick one of the other options you listed. But no one is going to tell me I need helium at 60m after using air for over 50 years, it’s what I know and what I was trained on. You may as well tell me to get in the shower and start tearing up money that it’s good for me.

 

[iliketopetsharks]

I've been with divers on Nitrox who are at 30m depth head up to 20m and have to end the dive after 30 mins due to using up their gas. It's not longer for everyone just because they stay shallower.

Are you trying to compare apples with onion soup? Same size cylinder lasts longer on a shallower depth, for everyone. Volume times pressure, remember?

 

[Wookie]

This is all quite entertaining and it's threads like these that keep the board alive. Great reading material!

Have we even defined what is "deep air" yet?
Or is that a moving target depending on who you talk to?
Someone once told me that people are idiots for breathing air at all, and only 32% is acceptable down to 100' and past that it has to be trimix.
Is that still a rule?

Yer gonna die if you dive (split fins, voodoo gas, an air2, deep air, solo, with a BCD, without a BCD, rebreathers, if you skip breathe, pick any of them) is the only rule.

 

[Blackcrusader]

Are you trying to compare apples with onion soup? Same size cylinder lasts longer on a shallower depth, for everyone. Volume times pressure, remember?

Really? So everyone has the same sac rate? So I dive with a SAC rate of 8l/min yet a diver with a sac rate of 15l/min will have the same longer shallower dive? News to me. This is a shallow dive. 93 mins finished with 50 bar on an AL 80.

Other divers on the same dive were at 50 bar after an hour. How long an AL80 tank with 2200 liters of gas lasts depends on the volume being used by the diver would not not agree?