Weird experience today - ox tox warning

[Scubaholic]

Vytec:

Dive One is the same, except max 140, and except for showing a mere six bars as max OLF.

Dive Two, the same as above, and only four bars showing as a max OLF.

Ok, what gives? Same computer company, same algorythms, I assume. The tingling in my lips was probably coming from the fact that I got two hours sleep that night.

But how could my computers be so differnet, when the personal settings are the same for each unit?

 

[Scubaroo]

The Dive Log software recalculates your profile based on the sampling, which is every 10, 20 or 30 seconds depending on what you've set it to. The Vytec OTOH will show the final profile based on a 1 second sampling. The Vytec is more accurate than what's in Dive Log.

 

[mempilot]

2. Use my 27cf pony as my deco/safety stop gas. Rather than using 100% at 20fsw, I'll probably settle for 70%, so I can start using it a little deeper, and offgas longer.

In a previous post, you stated that you also partake in decompression diving, and that you are a technical diver. I'm interested in your choice of deco gas. You say, "I'll probably settle for 70%..." I've never heard of any deco diver settling on or using ean70. Some have used ean80, but that was proven to be a 'not so smart' choice of gas by what some in the industry would call a strokke. Most use ean50 and 100% for decompression, but there are other gasses used for travel gasses.

By your comments, it doesn't sound like you have developed a standard for yourself, which would imply that you are not anywhere near as experienced as you are trying to come off.

I dive 1.6 PO2 on normal recreational dives, but I plan this based on a hard bottom where I can't blow it. I don't do the whole dive with my belly in the sand either. On deco dives, I plan 1.4 for the working portion of the dive and 1.6 for deco.

Currious, what agency did your Nitrox, Advanced Nitrox, and your Decompression Procedures certification?

 

[Scubaholic]

If I can step away from mempilot, I think the thing I have learned from this is that it is easy, even for experienced divers with hundreds of fairly advanced dive to become somewhat brain dead about the technical aspects of diving. For several years my philosophy has been "I dive when my computer tells me I can dive." So, for those that suggested that I brush up on the books, I can only say the point is well taken. I also am going to get a new computer, because I now think my Cobra is a POS, but that is another matter.

 

[Scubaroo]

Scubaholic,

Try and play nice please. ScubaBoard isn't meant to be somewhere for divers to fight or belittle each other. You were asked a valid question, please try to respond in a courteous manner.

cheers

 

[MikeFerrara]

Technical divers who get into CNS O2 Tox usually also have a significant decompression obligation at the time. This means that they cannot be taken quickly to the surface. While a diver is convulsing their airway is usually closed so you must keep them at constant depth until the convulsion is over. Then you need to recover their second stage and hold it against their mouth so that you are ready to give them air when they start to breathe again.

I don't have the numbers to prove it but most technical divers who tox do so because of a wrong gas switch. I bold a portion of you're statement above to point out that it might be better to put the toxing diver on your long hose rather than theirs. After all they toxed and you didn't. The gas they were breathing might not be the gas to put them on when and if they start breathing again.

I only know of one instance of a toxing diver being rescued and brought up through deco and that was AG with a student.

GUE now teaches the method which also includes purging the reg some so that there's something other than water in front of them.

I don't know if it will work a second time but I don't have any better suggestions either.

Lots of us choose to keep our PPO2 low for the working portion of the dive and save the O2 slam for deco. When I say low, I mean even lower than the 1.4 that most recreational agencies teach. We do back gas breaks prior to gas switches (on long dives) and periodically after and especially while on O2 at 20 ft.

 

[Scubaholic]

Lots of us choose to keep our PPO2 low for the working portion of the dive and save the O2 slam for deco. When I say low, I mean even lower than the 1.4 that most recreational agencies teach. We do back gas breaks prior to gas switches (on long dives) and periodically after and especially while on O2 at 20 ft.

Mike, I'd like to hear more about that, if possible. What do you consider the "working" part of your dive. Obviously, at depth, and I assume that could apply to someone doing salvage, hunting fish, taking photos of a wreck, whatever.

Also, everyone has a different seizure threshold. An epileptic, for example, has a low seizure threhold and has to take meds to raise that threshold. Have there been studies that would demonstrate if one's seizure threshold plays a part in susceptibility to oxygen toxicity? A correlation, IOW.

 

[mempilot]

There are several agencies with these courses. I was just curious which one did yours. Sorry you took that question so personal. It just helps to understand what your background is.

What was the purpose of your post if not to get responses from members. Some attacked you. All I did was comment on your choice of mix and ask a question about which agency you certified with.

Sorry if you are offended by that.

 

[Scubaholic]

Mempilot, I can get in up to seven dives on most days I go out. If I can find the time, I can get out five days in a month. That would be about 35 dives right there in a single month. If I can do that for six of the 12 months, then that is 210 dives for half the year. If I can sprinkle in another 80 dives for the rest of the year, then that would explain it.

I have Nitrox, Advance EAN, Advanced Diver, Decompression Procedure, and Adnaved EAN. I have picked-up some good things from the classes, and don't want to say anything on here to discourage anyone from training (not that at this point I have much credibility).

The 70% mix is not based on a study. It is based on a compromise of sorts. A 100% I am not real crazy about because it is only good at 20 ft. It is also deadly if you start hitting it lower then planned. There are plenty of those that will tell you they dive with a 50 -65 and that it is also there "worst case scenario" bail out bottle, figuring that they can survive a few breath of it while quickly climing to a safe PPO depth. To consider a gas with a dangerously high PPO as a possible bail-out bottle is obviously very controversial, and would result in a rain of Darwin insults.

So, the 70% is somewhat arbitrary. I have not run all the different scenarios to discover the perfect mix. 50% is not a bad idea.

 

[Scubaholic]

This question is an interrogation? "Curious, what agency did your Nitrox, Advanced Nitrox, and your Decompression Procedures certification?"

There are several agencies with these courses. I was just curious which one did yours. Sorry you took that question so personal. It just helps to understand what your background is.

What was the purpose of your post if not to get responses from members. Some attacked you. All I did was comment on your choice of mix and ask a question about which agency you certified with.

Sorry if you are offended by that.

Ferreting through some of the posts had me a little on the defensive. I will now be the model of good citizenry on this forum.