Best Mix VS Standard Gasses (split from a GUE fundies course report)

[Manatee Diver]

It’s too rich for mine too.

Brb while I sob into my credit card bills

The more I look at trimix the more it looks like a CCR only thing.

 

[PfcAJ]

The more I look at trimix the more it looks like a CCR only thing.

Rebreather helps. I dive an RB80, and I would be very limited in the trimix diving I could realistically do without it.

I think there is tremendous value in learning (and getting good at) OC trimix before moving to a rebreather, but for frequent trimix diving, it’s almost a necessity.

 

[stuartv]

If the plan was 100’ with alternates to 120, I’d simply shift to the next deeper standard gas of 30/30.

Too easy.

The only GUE Standard Chart I could find says EAN32 to 100', TX21/35 from 110 - 150. I reckon it's pretty old.

Can you point me at a current chart of Standard Gases with depth ranges?

Related: The following is a real-world scenario. Can you (or anyone that knows the "correct" GUE answer) tell me what gas you would choose?

You're going to dive on a boat out of Morehead City or Beaufort, NC. They are never able to say for sure what wrecks you will be going to dive until the morning of, as you're heading out of the harbor. Even then, the sites could change. All you know, the day before, is that you will be diving somewhere between 70 and 125'.

What do you get your tanks filled with?

 

[rddvet]

The only GUE Standard Chart I could find says EAN32 to 100', TX21/35 from 110 - 150. I reckon it's pretty old.

Can you point me at a current chart of Standard Gases with depth ranges?

Related: The following is a real-world scenario. Can you (or anyone that knows the "correct" GUE answer) tell me what gas you would choose?

You're going to dive on a boat out of Morehead City or Beaufort, NC. They are never able to say for sure what wrecks you will be going to dive until the morning of, as you're heading out of the harbor. Even then, the sites could change. All you know, the day before, is that you will be diving somewhere between 70 and 125'.

What do you get your tanks filled with?

It can be hard to find the actual breakdown on standard GUE gases on the internet surprisingly. I'm not GUE trained (though in retrospect I wish I started with GUE but had no clue what it was many many years ago), but I generally use the GUE standard gases. They make life easier. You can also google UTD's standard gases. They're farily similar if my memory serves correctly with some changes like 25/25 over 30/30. There may be other difference, but I didn't look very hard since I've already been taught the GUE ones.

 

[seeker242]

Can you point me at a current chart of Standard Gases with depth ranges?

There really isn't an official chart with depth ranges. At least I have never seen one. The guideline is to limit the max END to 100', without exceeding 1.4 pp02 on rec dives and 1.2 on working portion of tech dives. Using 32, 30/30, 21/35 or 18/45 and whichever gas will do that is what you would use.

All you know, the day before, is that you will be diving somewhere between 70 and 125'.

What do you get your tanks filled with?

100% by the book in every possibility? 30/30 and stay 5' off the bottom. However, no one will come to arrest you if you are not 100% by the book, 100% of the time.

 

[CAPTAIN SINBAD]

UTD standard gases and depth chart is on page 226 of the manual.

https://aquatec.files.wordpress.com/2012/02/procedurespreviewv1_1.pdf

 

[stuartv]

There really isn't an official chart with depth ranges. At least I have never seen one. The guideline is to limit the max END to 100', without exceeding 1.4 pp02 on rec dives and 1.2 on working portion of tech dives. Using 32, 30/30, 21/35 or 18/45 and whichever gas will do that is what you would use.



100% by the book in every possibility? 30/30 and stay 5' off the bottom. However, no one will come to arrest you if you are not 100% by the book, 100% of the time.

Then how does anyone know what the GUE Standard Gases are? Apparently, UTD has Standard Gases that are different. It's starting to sound like "Standard Gases" really are not standard at all.

And yes, I want to know 100% by the GUE book. I want to know what a GUE diver would do if they were strictly following their training.

I can see how "TX30/30 and stay 5' off the bottom" would possibly be the answer (presuming that TX30/30 is an official GUE Standard Gas). That is the answer I came up with, anyway.

Whether I would want to pay for 30% helium on every NDL dive (including the ones to 70') down in NC is a whole nother question. My LDS is the cheapest shop I know for helium and they charge $1/foot. $30 of helium in one HP100, for one dive to 70'.... Hmmmm... $60 gas bill for a 2-tank dive day.... $72 in gas to do 2 dives with my double 120s... The other LDS charges $1.50/ft. $108 in gas for 2 dives....?

Or, more applicable to most folks. $1.50/ft and 2 x single HP100s. $90 in helium for 2 NDL dives.

Standard Gases may sound nice on paper, but does the concept really survive contact with the real world? I mean, the real world of places that don't conveniently have their depths lined up with one row on the Standard Gas chart? If all your possible sites are all fine on EAN32, that is great, but it seems like there are a lot of places where that doesn't work.

 

[seeker242]

Then how does anyone know what the GUE Standard Gases are?

The standard rec gas taught in fundamentals is 32. Tech 1 is 30/30, 21/35 or 18/45.

Standard Gases may sound nice on paper, but does the concept really survive contact with the real world?

Yes, it's not exactly normal to not know what depth you will be diving to. And if you are diving below 100' without he, then you are already outside the standard.

 

[PfcAJ]

100 = 32%
120 = 30/30*
150 = 21/35
200 = 18/45
250 = 15/55
300 = 12/65

*30/30 is a weird one. I wanna say GUE calls that a 100ft has but when I went through the curriculum it was MOD 120ft. Makes sense to me so I roll with that.

 

[PfcAJ]

The only GUE Standard Chart I could find says EAN32 to 100', TX21/35 from 110 - 150. I reckon it's pretty old.

Can you point me at a current chart of Standard Gases with depth ranges?

Related: The following is a real-world scenario. Can you (or anyone that knows the "correct" GUE answer) tell me what gas you would choose?

You're going to dive on a boat out of Morehead City or Beaufort, NC. They are never able to say for sure what wrecks you will be going to dive until the morning of, as you're heading out of the harbor. Even then, the sites could change. All you know, the day before, is that you will be diving somewhere between 70 and 125'.

What do you get your tanks filled with?

I’d consider being prepared with 32% and gas for something deeper. Maybe 30/30 in one of them (assuming single tank dives).

I personally keep one of my shallow stage bottles filled with 32% and another with 30/30 so I can use the appropriate one based on the dive.