Complacency or Confidence?: Follow Up

[Cantey]

I don't see why people DON'T analyze their tanks. It takes a few seconds, and it's saved my life more than once.

seriously, I agree...and I can't believe the look I got once from a well known shop owner that I wanted to know where the analyzer was. The look was like..."what, you don't trust my blending?"

I also don't analyze tanks for anyone else...

[Jim Wyatt]

And I'd like to add if you dive nitrox, you should OWN your own analyzer,

Rich

Agreed.

And also if you only dive air and get your tanks filled at a place that pumps anything in addition to air.

[Burke]

There are lots of variables in cave diving that we can't control, but this is one that we can and it is very important that we do! For example, within the last year, I got what was supposted to be a 100% O2 fill that was actually 60%.

The same thing happened to me. I had used my O2 bottle on two different dives. After the second dive, I went back for a top off and there was a problem. When the tank was analyzed it was 60% O2 and 5% helium. Interesting that you had the same percentage (60%). I wonder did you check for Helium? After that incident, I bought my own analyzer.

I get funny looks at the dive shop when I analyze what is supposed to be 100% O2. But, you can't be sure someone didn't have a valve in the wrong position and fill your O2 bottle with something else.

[Line Squirrel]

Hmmm, this might make an interesting poll... but no shop names.

[saturation]

I've found many problems getting fills that can only be found by religiously analyzing all your gases so it becomes a reflex habit.

You should own your own analyzer, you can make the Oxychek El-Cheapo for about $100, includes the first 02 sensor.

[Hydrogirl]

A couple of weeks ago, we were having problem with mixes at the shop I work for.
It was the O2 from our local vendor was 88%.

[jimdiverman]

Hmmm, this might make an interesting poll... but no shop names.

I always anaylze my gases, and I find it particularly important when I am switching from Nitrox on one day doing a shallower cave, to a deeper system on the following day, and I am topping off my mix with air. I need to figure out the maximum amount of a certain mix I can have in my tanks at the end of the dive before the air fill to try to have a low enough MOD to dive the deeper cave the next day. In the past I have been surprised how high the O2content still was in the tanks after an air fill on top of the remaining 32% mix. I like to be conservative so I want to make sure I can go a little deeper in an emergency if I need to, so my backgas needs to support the emergency MOD.

[Line Squirrel]

I always anaylze my gases...

Did you see the poll?

http://www.cavediver.net/forum/showt...1022#post51022

[jmaddox]

I’m interested to see what level of accuracy yall think is acceptable. I think I remember from my nitrox class a decade or so ago that there was some rounding that took place and the mix should be within 1%. i.e. + or - 1%. I’ve been fooling around (no not like that guys) with my analyzer and cannot seem to get consistent readings. Mine reads to 1/10th of a percent i.e. 32.x%. Is there an analyzer that is "lab quality" on the market that might read to say 1/100th of a %? (that’s not bench size and costs 1K or more) seems to me that with an inconsistent instrument and slight differences in mix could result in a cumulative error of at lease a % or 2. 32 vs. 34. For me that’s bordering on unacceptable. anyone else agree. Am I way off the mark here? Id just like to really know what’s actually in my tanks.

thanks

--jm

[Line Squirrel]

This is just me...

I dive to 1.2ppo2 (working portion of my dive) so it's not a huge deal if I'm +/- 1% as far as MOD goes.

I round down when I put it in my computer for deco purposes.

32.5% ~ round up to 33% for mod, round down to 32% for the computer.

An analyzer that will give you two decimal places out will only cause premature grey hair.