Fatigue After Diving

[PfcAJ]

O.K. - that's what I'm using as a Bottom Mix for the same depth and I switch to the 50% as well... but I also add an 80% at 9m (02 is not as readily available here as a deco gas) as well as sometimes breathing it on the surface for a few extra minutes after the dive and I feel fine. When doing a deep air dive at the same depth 50-55m (using 40% and 80%) over a period of days I definetly feel a little more fatigued.

So perhaps consider adding 80% or 02 as your shallowest deco gas - this should help. Also definitely experiment with GF settings... try a shallower "deep stop" as in a higher Low GF and adding a little more time on your High GF (assuming you're running Buhlmann GF ) I don't use VPM so can't advise on that.

How do you make 80% with no o2?

 

[shoredivr]

How do you make 80% with no o2?

That *is* a question.

 

[Nasser]

How do you make 80% with no o2?

Meaning that the dive centers here generally offer 80% as the more common deco gas of choice for OC tech dives when renting/purchasing.... not because they don't have O2 to mix nitrox.

 

[PfcAJ]

"bro, fill my tank with o2"

easy.

 

[Nasser]

"bro, fill my tank with o2"

easy.

Not even a consideration... 80% works just fine for most of us.

 

[tomfcrist]

I think what AJ is trying to say is this( correct me if I'm wrong )...

To fill 80% you have to start by putting 2241psi of O2 in the tank.
Assuming an AL 40 that is nearly 30 cuft of O2... That's a lot of freaking gas. Like enough for 30-45 minutes of deco at 10-20'. Add on the fact that pure O2 is more efficient in washing out nitrogen...it's a win/win.
If you need more than 30cuft...take an 80 for deco.

 

[Nasser]

I think what AJ is trying to say is this( correct me if I'm wrong )...

To fill 80% you have to start by putting 2241psi of O2 in the tank.
Assuming an AL 40 that is nearly 30 cuft of O2... That's a lot of freaking gas. Like enough for 30-45 minutes of deco at 10-20'. Add on the fact that pure O2 is more efficient in washing out nitrogen...it's a win/win.
If you need more than 30cuft...take an 80 for deco.

Yes I understand, but to my knowledge a few of the centers here are limited in what they can provide... primarily because they don't have boosters to get O2 or even 80% to higher pressure levels so you end up getting a 10L or 12L with 100 BAR to get enough gas. Actually here in Jordan there is only one dive center that provides Nitrox of 40% and over (and they don't have a booster). Even n Egypt (Sharm, Dahab etc.. ) I have primarly seen 80% as a more common standard rather than O2 - and they do have boosters there.

But the main reason is that there generally hasn't been a need to ask for anything more than 80% as from a deco efficiency (as in time saved) it is somewhat negligible. Not saying the using O2 isn't a good idea, just that it's not common here as a deco gas and it's not even a consideration to ask for it. The only time I've actually had to use O2 is during oxygen adminstarion and rescue courses.

P.S. Please excuse my use of BAR's and Liters.

 

[descent]

Please excuse my use of BAR's and Liters.

No problem. Doing the mental conversions is good exercise.

... a few of the centers here are limited in what they can provide... primarily because they don't have boosters to get O2 or even 80% to higher pressure ... in Jordan there is only one dive center that provides Nitrox of 40% and over (and they don't have a booster). Even n Egypt (Sharm, Dahab etc.. ) I have primarly seen 80% as a more common standard rather than O2 - and they do have boosters there. ... But the main reason is that there generally hasn't been a need to ask for anything more than 80% as from a deco efficiency (as in time saved) it is somewhat negligible. ...

This reminds me of an epic pissing contest from last July, full of well-stated opinions on all sides of the issue, with just about every degree of vehemence: If you had to choose, 80% or 100% for deco gas and why.

 

[tomfcrist]

Fwiw..I don't have a booster either. It is no problem to fill O2, nitrox, trimix etc...without a booster.

 

[dreamdive]

The subjective "feeling better" not only has been questioned but disproven in the case for Nitrox diving. I believe that is true for deco diving, as well. The issue of what gradient factors or algorithm to dive appears to be a very touchy subject, but more importantly, it is a personal one. I also believe that before anybody uses any algorithm, they need to understand as much as possible about it.

As others have already suggested, your feeling tired may be due to engaging in an activity you are no longer used to. We just finished our expedition seminar in Cayman, and swimming with two 80's (as bail-out) in surging water and against a current had an effect on all participants. We all turned in early the first two nights.

Rather than guessing what is 'good' or 'bad' for you and diving, look for information that is based on scientific evidence. The world of diving is full of myths and dive gods. Incidentally, we are holding free seminars on various topic next weekend during the Grand Opening of AddHelium. I don't know where you are in Florida, but if you are close to Ft. Lauderdale, stop by. It's not just for CCR divers, but any diver (OC tech and recreational divers) will be walking away from it having learned something new.

Lastly, it is my opinion that if you want to do something good for you during deco, add additional time on your last two stops.

Good Luck and Safe Diving