Systematic use of oxygen analyzers by advanced divers ? [Poll].

[chillyinCanada]

Well, I could always try to ask PADI to send me the contact information of a sample of 100,000 randomly selected divers from their database, but somehow I have the intuition that this information will probably not be readily accessible to me..

In that event, why are you doing a poll in the first place? What is your personal practice and what's it to you what scubaboard members or 100,000 PADI divers do?

 

[chillyinCanada]

I’m just not sure what you are trying to learn from this poll. Most divers on ScubaBoard are going to say they always test their gas. Period. But that really doesn’t tell you a thing. Because regardless of what this poll says, I can tell you that the majority of (nitrox) divers IRL do not test except when required by shop (when picking up tanks, analyze and fill out dive log) or the operator (on a liveaboard, for example).

I’ve included just two (of many) of my experiences below:
When I was diving Nitrox at a big name recreational op in the Bahamas, the tanks came out with a sticker on them that had the percentage of oxygen only. No date, no initials. I asked the deckhand if I could analyze the tanks (I had not brought my analyzer as it was a family trip and I was just diving recreationally a couple days). The deckhand explained to me that I did not need to analyze the tanks because they had analyzed them for me. I explain to him that I was breathing the gas so I wanted to verify the oxygen content. You would have thought I was asking to start up the compressor and fill my own tanks! Eventually, they brought the shop analyzer out and analyzed the tanks with me watching. (Point - obviously my request was atypical)

On a group trip to Indonesia, again, tanks came out with stickers with O2 percentage and nothing else. This time when I asked, however, they were happy to let me analyze my tanks, on a daily basis. However, the group leader (a DM) basically chastised me for wanting to analyze my tanks. Her reasoning? That the Nitrox was banked - so the tanks had to be right!

Your first story, I've had the exact same happen. Your second story, very similar.

 

[Gareth J]

On a group trip to Indonesia, again, tanks came out with stickers with O2 percentage and nothing else. This time when I asked, however, they were happy to let me analyze my tanks, on a daily basis. However, the group leader (a DM) basically chastised me for wanting to analyze my tanks. Her reasoning? That the Nitrox was banked - so the tanks had to be right!

As you can see from my previous post, I strongly believe you should retest cylinders when you fit the regulators just before diving.

I can see some justification for the DM's comment. If all cylinders where ONLY filled from the bank, and then tested as they come off the bank.
However, I personally would still test my own cylinder.
The advantage of filling from the bank is the risk of a mistake during the blending is significantly reduced. However, this doesn't stop cylinders that are air topped having a weaker mix. Or a cylinder of air being used in place of a cylinder of Nitrox by accident.

If you don't test the cylinder, you are doing a trust me dive!

Some one mentioned saving time by one person testing the cylinders for a group.
This is OK when picking up the cylinders from the shop, but each individual should still test their cylinder as they put the kit together.
In the past I have either picked up cylinders from a shop from for friends or students, or mixed the gas myself. I teach students to test and sign for the gas when they take the cylinder from me. Those friends I have picked cylinders up for, would always retest the cylinder before use, if they didn't, I wouldn't pick the cylinder up.

Gareth

 

[lv2dive]

I typically test my gas at home before going to the dive site or at the dive site, if I got fills. Basically, right before I put the regs on.

Better to also test when picking up the tanks, too, to prevent situations I ran into a few years ago - I analyzed my tanks at the dive site and to my surprise, they were really hot -36% if I recall correctly. This was surprising to me as the shop banked 30 or 32%. Of course I immediately called the shop - they apologized profusely - someone had accidentally bumped the calibration up. (Luckily we had multiple options where to dive so I was able to use the tanks)

 

[admikar]

I test for nitrox, for air I don't. I dive only my own tanks. While I understand possibilities for error to happen, at this moment, for me, they are really really slim. Nobody else is using my tank, compressor I'm using is filling only air, there are no other gas tanks at all. So far, my dive trips were always with my club, if air fills-O2 tanks are on the other side of the room from compressor, intake is from outside. If nitrox-O2 tanks are connected to a blender, intake is connected to a blender. Since I'm dubiously awarded with filling nitrox most of the times, I'm quite sure when there is more O2 in my tank than normal air. Therefore, answer is other.

 

[TMHeimer]

Just thought of an interesting side question. What about courses? We know that shop staff don't re-check 36 tanks that have just been filled last night for the next OW course. And we know the instructor/DM or students themselves don't re-check these tanks.

 

[CT-Rich]

Air I don’t check. Nitrox is tested and logged. SOP.

 

[BRT]

Air I don’t check. Nitrox is tested and logged. SOP.

The question is...how do you know it is air?

 

[CT-Rich]

The question is...how do you know it is air?

They charge more for nitrox.

Most of my local diving would not be affected if I did dive nitrox. On vacation I use nitrox because because it comes with the package and I will make 4 dives a day. I am to old/lazy/cheap to do balls to the walls deco diving and need/want exotic gas mixtures. Unless they hook my tank to the exhaust of a deisel truck I am getting 21% O2.

A typical day of diving for me is two dives max depth 60 fsw. Getting nitrox would just increase the safety margin of an already safe dive, since my computer and my plan would be built around the assumption of it being air. If I was going to make a more challenging dive, I might check.

I also assume the shop knows my tanks, devoid of any labels indicating mixed gases, get filled with air. My ex wife might be tempted to spike my with tanks with cheez-whiz or something, but not until next summer, when I am done with child support payments....

 

[BRT]

They charge more for nitrox.

Most of my local diving would not be affected if I did dive nitrox. On vacation I use nitrox because because it comes with the package and I will make 4 dives a day. I am to old/lazy/cheap to do balls to the walls deco diving and need/want exotic gas mixtures. Unless they hook my tank to the exhaust of a deisel truck I am getting 21% O2.

A typical day of diving for me is two dives max depth 60 fsw. Getting nitrox would just increase the safety margin of an already safe dive, since my computer and my plan would be built around the assumption of it being air. If I was going to make a more challenging dive, I might check.

I also assume the shop knows my tanks, devoid of any labels indicating mixed gases, get filled with air. My ex wife might be tempted to spike my with tanks with cheez-whiz or something, but not until next summer, when I am done with child support payments....

Money is a powerful motivator, but I still think it possible to get a tank of 36% instead of air if 36% is available at the shop. My theory is that I am unlikely to be at depth for enough time for an accidental tank of nitrox to tox me.