Nitrox analyzer: to take or not to take?

[stuartv]

I went diving in Hawaii a couple of years ago. I made arrangements to meet my guide from the shop I booked through at the dive boat. I also pre-booked to dive Nitrox (32). I showed up at the marina. My guide showed up with my tanks. My guide did not have an analyzer. The boat did not have an analyzer. I dived the tanks of air that the guide had brought for himself.

I bought my own analyzer as soon as I got home and I take it with me any time I go to dive anywhere. You never know when the shop/boat's analyzer will break in the hands of the person right in front of you in line...

 

[yle]

How much do you all trust the nitrox analyzers that dive ops around the world make available?

My experience in Cozumel a few years ago convinced me I should always bring my own analyzer. I had requested four nitrox tanks, one for each of the four divers in my group. The morning of the dive, the four tanks were delivered and the DM had already analyzed them. They were all supposed to be 32%, and he told me that he confirmed they were.

I took out my analyzer and started to test them myself; he protested... I think he was kind of offended because he was doing his best to deliver what he thought was "customer service" and I wasn't acknowledging it. Unfortunately for him, two of the four tanks tested to 21%.

He insisted my analyzer was wrong, and showed me how his analyzer measured 32% for all four. I then had to show him that he wasn't calibrating his analyzer properly... he would test one 32% tank, then put the analyzer directly on the next tank (which was 21%). The analyzer would read the residual 32% gas still in the analyzer tube.

After the DM had been educated on proper analyzer use, he was able to confirm my readings of 21% for the two tanks. He then agreed to replace the tanks with two others.

Made me wonder... how many other "nitrox" tanks had been used by guests of that dive op that actually had normal air? Impossible to say... but I didn't see anyone else bringing their own analyzer and half of my "nitrox" tanks were wrong. Extrapolate from there.

The other part of this experience: the DM was not interested in making their analyzer available to guests. He seemed very adamant that he analyzed the tanks with the shop's analyzer and that was just the way they did it.

 

[BRT]

"I then had to show him that he wasn't calibrating his analyzer properly... he would test one 32% tank, then put the analyzer directly on the next tank (which was 21%). The analyzer would read the residual 32% gas still in the analyzer tube."

What is your procedure between tanks?

 

[caruso]

the DM was not interested in making their analyzer available to guests. He seemed very adamant that he analyzed the tanks with the shop's analyzer and that was just the way they did it.

A diver should analyze his or her own tank it's a PADI rule. Call the scuba police on that guy!

 

[doctormike]

My experience in Cozumel a few years ago convinced me I should always bring my own analyzer.

Cool story, but really just shows that you should analyze your own tanks, not that you need to bring your own analyzer. Of course, if they wouldn't LET you use the shop analyzer, then you would need your own, but that might be reportable to an agency or something...

 

[scubadiver888]

How much do you all trust the nitrox analyzers that dive ops around the world make available?

I usually work against a conservative PPO2 of 1.2 so the mix would have to be a number of points off before I'm in real trouble, but I would have no way of knowing how wrong it is.

So far my international nitrox travel has been Mexico and the Caribbean, but I'm looking at Truk and a few other places in the next few years.

I'm heading to the Cayman Islands next month for a lot of nitrox diving and got to thinking about this and the unlikely possibility of a Black Friday sale on an analyzer.

Anyone worry about this kind of thing?

(P.s. as usual, sorry if this has been discussed; you know searching can be here sometimes.)

This is timely for me. I have a lot of diving experience in Caribbean and Mexico but I'm going to the Philippines in April. I haven't started thinking about what to pack but now I'm wondering if I should bring my analyzer.

Thanks for asking this. After reading a few of these I'm thinking I should bring my own analyzer to be safe. I've seen some analyzers which the shop says are calibrated and I just need to use them. Once in Cayman Brac the analyzer seemed off. So the staff re-calibrated the analyzer and checked my tank again. This time it was closer to the expected 32%.

 

[yle]

A diver should analyze his or her own tank it's a PADI rule. Call the scuba police on that guy!

Cool story, but really just shows that you should analyze your own tanks, not that you need to bring your own analyzer. Of course, if they wouldn't LET you use the shop analyzer, then you would need your own, but that might be reportable to an agency or something...

Actually... the PADI nitrox course teaches that an acceptable method of a diver analyzing their own tanks is to have someone (e.g. a shop rep) work the analyzer while the diver observes the reading. Which means the method the guy was using was technically PADI approved. Of course PADI assumes the person is working the analyzer in a way that will give an accurate reading.

 

[doctormike]

Actually... the PADI nitrox course teaches that an acceptable method of a diver analyzing their own tanks is to have someone (e.g. a shop rep) work the analyzer while the diver observes the reading. Which means the method the guy was using was technically PADI approved. Of course PADI assumes the person is working the analyzer in a way that will give an accurate reading.

I thought that you said that the issue was that you were given tanks and you were told that they were already analyzed, which is the thing that isn't PADI approved.

By "analyze your own tanks" I mean that you shouldn't accept a tank with the understanding that someone else has analyzed and labeled it. If you are there, it doesn't really matter who is actually holding the analyzer. Just make sure that if a connecting tube is being used that the gas runs long enough to flush out the old gas, and let the gas flow long enough for the reading to stabilize.

 

[yle]

I thought that you said that the issue was that you were given tanks and you were told that they were already analyzed, which is the thing that isn't PADI approved.

By "analyze your own tanks" I mean that you shouldn't accept a tank with the understanding that someone else has analyzed and labeled it. If you are there, it doesn't really matter who is actually holding the analyzer.

Oh yeah, that was initially what happened: I was told the tanks were already analyzed by the DM using his analyzer. I insisted on analyzing them myself. He then offered to show me how he analyzed the tanks using his analyzer (which produced an incorrect reading.) My point was that PADI approves this, but assumes that the person holding the analyzer knows how to use it correctly.

Just make sure that if a connecting tube is being used that the gas runs long enough to flush out the old gas, and let the gas flow long enough for the reading to stabilize.

Exactly... the process can be challenging if they don't want you touching their analyzer but they're not using it correctly.

 

[TheGraveyardDiver]

I always bring my analyzer along.

Some of the guys and I went on a trip to florida for 2 weeks. We brought our own cylinders, about 16 total. We took them to a dive shop in the area we were staying and had them filled every day after diving. When we picked them up later in the day they were all ready and labeled 32%. Fine.

But on the boat right before the dive I analyzed mine, 26%.

After bringing up the issue with the guy who was doing our filling that week, I learned that this shop doesn't actually "analyze" the cylinders.
They label them with whatever they put in them. We asked for 32%, so they filled them with 32% and slapped a 32% label on them.

The problem was that they didn't drain the cylinders and some of the cylinders we delivered to them were as much as half full with air, or half full with other blends.

I had never heard of a shop doing this before, and it seems to me that would make them and their insurance company very sue-able, but that's how they did it. I just refuse to trust my life to some 16 year old fill station monkey. An analyzer is cheaper than a chamber ride because me and my computer thought we were diving 32% when we were really diving 23%.