Deco Gasses

[FireInMyBones]

The reason for 100% is that with anything less you are still on gassing Nitrogen.

 

[hypertech]

I'm not a tech diver, but I don't think that's true. As long as the partial pressure of nitrogen in the tissue is more than the gas, you will be off gassing, no?

 

[netmage]

I'm not a tech diver, but I don't think that's true. As long as the partial pressure of nitrogen in the tissue is more than the gas, you will be off gassing, no?

O2 is simply the most efficient...

 

[Captain12Pk]

I am sure this is true, but one may start assembling the necessary O2 cleaned equipment before the class, I assume?

Using O2 clean regs and such with Nitrox < 40% is not a problem, right? Especially when the method of blending is partial pressure and the bottles are O2 clean anyway.

Sure. No reason you can"t start acquiring your gear now. But I'd suggest talking to your instructor of choice first. Just to make sure what you're buying is what he or she requires you to have. Buying gear twice gets expensive quick.

 

[Jax]

Sure. No reason you can"t start acquiring your gear now. But I'd suggest talking to your instructor of choice first. Just to make sure what you're buying is what he or she requires you to have. Buting gear twice gets expensive quick.

Not sure I like the sound of that. I should buy what equipment the instructor wants me to have, and not make my own choice?

 

[PfcAJ]

Choice of deco gas depends on the dive. The "work" required to maintain all of them is exactly the same, however.

50% might be a far better choice than 100% for one dive, but that certainly would not be true for another dive. It just depends.

Example: Wreck dive to 150' for 20mins. 50% makes sense there.

Example 2: Cave dive to 80ft for 100mins. 100% makes sense for that dive.

One is not "better", they are simply different.

 

[netmage]

Not sure I like the sound of that. I should buy what equipment the instructor wants me to have, and not make my own choice?

Ignore everyone else, instructor included, listen to CD and me....

 

[ianr33]

I'm not a tech diver, but I don't think that's true. As long as the partial pressure of nitrogen in the tissue is more than the gas, you will be off gassing, no?

But you will be offgassing fastest on oxygen.

 

[Captain12Pk]

Not sure I like the sound of that. I should buy what equipment the instructor wants me to have, and not make my own choice?

I learned the hard way too.

 

[netmage]

My inquiry is about pure oxygen as a deco gas. Is that what most people with similar diving interests are using? It seems like the time you save using 100% is significantly offset by the work required to keep tanks, valves and regs oxygen clean. If 100% is not the most common mix, what mix is, and if it's North of 40%, what extra gear issues do you have maintaining a system that's safe for say 80% vs. 100%? How often do you re-clean your tanks, valves and regs to maintain oxygen compatibility?

Tanks generally should be re-cleaned at hydro or when suspect of contamination...
Valves, yearly or every other...
Regs are generally rebuild yearly/every other year... It (should be) nothing to use O2 compatible kits and lube - but alas the LDS loves to up-charge this one to death....