Loose rules in Fort Lauderdale, FL

[MXGratefulDiver]

Depends on factors. If I have 32 or 30 in a tank (or the shop banks 32 or 30) and my dive is only at 100ft. I am not going to go through the hassle of getting 34%, I'll just use what is easier. For shallower dives, there is plenty of leeway on best mix.

Yeah ... pretty much. Best mix is nice if you're looking to optimize NDL ... but when it's not a factor, I prefer to stick with the familiar. It just simplifies keeping track of the variables one has to pay attention to when doing the dive ...

... Bob (Grateful Diver)

 

[iluvtheocean]

Nitrox in various blends is easy to get here helium not so much. only a couple shops carry it that i am aware of. most rec divers around here wouldn't have training on it with many being vacation etc.

 

[scuba5150]

Please do me a favor, go through analyzer adds like this one, or this one, or that one, etc. and find one add where accuracy or precision are disclosed.

Specs for the Analox analyzer - note the accuracy is +/- 1% of the reading not 1% of O2

 

[oly5050user]

And maybe you still believe in Santa? Oxygen analyzers used by divers in dive shops to check tanks are so inaccurate you can use them only to tell if you got air or some kind of Nitrox, and then trust in the guy who mixed it. But if I am already taking extra risk by diving solo, why would I add another risk factor? Risks do accumulate, just like errors.

This post is so wrong. It's almost funny.This is why you calibrate the analyzer before testing your mix.
Every tank you use should be tested by yourself. I do not know where tarponchik got her nitrox card, but I suggest going back and getting a refund, and learn about using an analyzer and how to calculate MOD for any mix. Here in the northeast we use 28% safely to 130' every weekend.

 

[chillyinCanada]

I can barely believe that you folks have been having this heated discussion for a couple days now and 13 pages! Well, yes, I can and do believe that. It's that you are having it in the Basic Scuba subforum that I'm surprised at. smh

This thread should be split or some darn thing. Why's there never a mod around when . . .oh hi John.

Tarponchik, wow, talk about sticking to your guns!. Now don't get me wrong. In principle, I think those of strong conviction should stick to their guns but they'd darn well better know they are standing on the highest ground, the firmest information. You look a little rocky there. May I suggest you end this now please?

And it would be nice if all the big dogs got off the pile too.

Tarpon, if you go first, you could still turn out to be the one on top. Never be afraid to say you're sorry when you've been wrong or misspoke or misunderstood.

 

[stuartv]

And it would be nice if all the big dogs got off the pile too.

Tarpon, if you go first, you could still turn out to be the one on top. Never be afraid to say you're sorry when you've been wrong or misspoke or misunderstood.

You realize, except for the last 4 posts or so, this thread is over 3 weeks old?

 

[Stoo]

Nitrox is made and checked with a certain margin of error, so "32" can mean anything from 30.5 to 34 (in my experience). And at 34 your max is already 103 ft. Then there is the error of your depth gage, etc. So if we trust the tables, I'd say "borderline".

Which is why you test the fill at the shop, and again just before diving. The pO2 standard of 1.4 is very conservative, but in a strong current, it's best not to get much higher than that.

Having said this, I always think that a 100' dive is the sweet spot for using nitrox.

 

[chillyinCanada]

You realize, except for the last 4 posts or so, this thread is over 3 weeks old?

Doh! No, I didn't notice that.

Oh well, nevermind. Though I still believe it should be moved to Advanced.

 

[tarponchik]

Specs for the Analox analyzer - note the accuracy is +/- 1% of the reading not 1% of O2
View attachment 380819

I do not trust these claims. The reason is, with every measurement you take, your sensor surface is slightly damaged. When O2 molecule binds to the sensor, the sensor generates some electric current. The higher the PPO, the higher the signal is since at equilibrium you have more bound O2's and more electrons are running out. However, every time some of the O2 molecules bind irreversibly, oxidizing the sensor surface. So you signal at given PPO becomes weaker and weaker, and the span of your oxygen meter electric output gradually shrinks.

This is OK if you calibrate your meter using 2 standards. But you only use 1 (air) which is just a zero adjustment for the ambient temperature (do not forget you have a 0.2% O2 shift per 1 degree C). You do not calibrate the span.

I've already mentioned a similar device, the pH-meter. It is using the same principle, and the electrode also does not last forever. So you calibrate using at least 2 standard buffers. This gives you both the zero value and the span adjustment. And I do not see why the oxygen meter would work differently. But instead you rely on manufacturer's warranty.

Probably the rules are just too conservative so it does not mater

 

[Mitch H.]

I like tacos. I eat them at least once a week.