NITROX CERTIFICATION PROTOCOLS - REAL WORLD

[lowwall]

Something else for thought. Don’t only test the tank yourself, test within a few hours of your dive. Many shops use partial pressure blending, mixing richer mixes with air to get to the mix you want. It can take a while for the gases to fully blend and the reading can change over time. So don’t just analyze your own tanks, do it At the right time.

It only takes a few minutes for the gasses to diffuse: How Quickly Do Gases Mix?

 

[drrich2]

So...what gives? Is this one of those things where you train ONE WAY but perform real world functions ANOTHER WAY??? Should I invest in an O2 analyzer. When diving should I insist that I personally test my tank. Will I be holding up the whole operation?

OR...SHOULD I JUST GO ALONG WITH THE CROWD AND TRUST THAT THE LDS HAS DONE THE LEGWORK?

The overwhelming majority of the time I've used nitrox, an analyzer has been available by the operator and the expectation was that the diver was to analyze his own tank and write the % in the log (often including date and MOD). Where live-aboards and CocoView Dive Resort were concerned, each diver had his one page in the log.

As you can see, the forum consensus heavily supports a strong emphasis on personal responsibility and analyzing yourself, or directly observing someone analyzing for you (some may trust a spouse to do it right). We trust dive op.s to maintain their compressors and most of us don't carry CO detectors (though I know of one SB member who's recommended it over the years), but it's recommended you analyze tanks.

That's understandable. If they partial-pressure blend, the mix % may be off. Maybe the fill station also supports tech. diving, and your tank might've gotten something else by mistake (note: but we don't habitually test air tanks). Crap happens.

So, what if you get on a boat where it's obvious the usual practice is that nitrox tanks are already onboard, there's no analyzer in sight, nobody is testing and your options are limited - ask discreetly hoping you just missed something (unlikely), raise a stink (e.g.: demand to analyze your tank or to cancel with a full refund over allegedly unsafe practices), go along figuring the risk must be pretty low or other people would've had trouble by now (safety in numbers mentality), etc...?

The mainstream SB answer will be that you do not use those tanks till you have analyzed them yourself, or observed them analyzed.

My answer is you have to decide for yourself. I've encountered this situation before...and I chose to do the dives and not raise a stink. Yes, I put my trust in people I don't know well personally, relied a bit on the safety-in-numbers approach, and treated it was a risk/benefit situation where I was willing to take the risk.

That's me making a decision for me. No way am I telling you it's the right (or wrong) decision for you. That is your call, and you live with the consequences of your decision.

That said...if you're willing to buy and maintain in working order an O2 analyzer, they can be pretty small, analysis doesn't take long, and I imagine other people on the boat will ask to borrow yours once they see you with it (if you're not willing to share, that can create awkwardness and ill will, so think about how you plan to handle the situation). If you're friendly, polite, non-confrontational and if questioned say something like 'No offense. I was trained so hard on this, it just gives me peace of mind if I analyze it myself,' I think that'll work fine.

Some may say you should confront dive op.s on their allegedly unsafe practice if they provide tanks without analyzers; that's up to you. I don't.

 

[BoltSnap]

The overwhelming majority of the time I've used nitrox, an analyzer has been available by the operator and the expectation was that the diver was to analyze his own tank and write the % in the log (often including date and MOD). Where live-aboards and CocoView Dive Resort were concerned, each diver had his one page in the log.

As you can see, the forum consensus heavily supports a strong emphasis on personal responsibility and analyzing yourself, or directly observing someone analyzing for you (some may trust a spouse to do it right). We trust dive op.s to maintain their compressors and most of us don't carry CO detectors (though I know of one SB member who's recommended it over the years), but it's recommended you analyze tanks.

That's understandable. If they partial-pressure blend, the mix % may be off. Maybe the fill station also supports tech. diving, and your tank might've gotten something else by mistake (note: but we don't habitually test air tanks). Crap happens.

So, what if you get on a boat where it's obvious the usual practice is that nitrox tanks are already onboard, there's no analyzer in sight, nobody is testing and your options are limited - ask discreetly hoping you just missed something (unlikely), raise a stink (e.g.: demand to analyze your tank or to cancel with a full refund over allegedly unsafe practices), go along figuring the risk must be pretty low or other people would've had trouble by now (safety in numbers mentality), etc...?

The mainstream SB answer will be that you do not use those tanks till you have analyzed them yourself, or observed them analyzed.

My answer is you have to decide for yourself. I've encountered this situation before...and I chose to do the dives and not raise a stink. Yes, I put my trust in people I don't know well personally, relied a bit on the safety-in-numbers approach, and treated it was a risk/benefit situation where I was willing to take the risk.

That's me making a decision for me. No way am I telling you it's the right (or wrong) decision for you. That is your call, and you live with the consequences of your decision.

That said...if you're willing to buy and maintain in working order an O2 analyzer, they can be pretty small, analysis doesn't take long, and I imagine other people on the boat will ask to borrow yours once they see you with it (if you're not willing to share, that can create awkwardness and ill will, so think about how you plan to handle the situation). If you're friendly, polite, non-confrontational and if questioned say something like 'No offense. I was trained so hard on this, it just gives me peace of mind if I analyze it myself," I think that'll work fine.

Some may say you should confront dive op.s on their allegedly unsafe practice if they provide tanks without analyzers; that's up to you. I don't.

If a dive operation doesn't supply an O2 analyzer and I can test it myself before using the tank, no way I am going to trust them on "good faith" at all. I'd skip the dives and/or change dive ops. That's why I have my own O2 analyzer (two of them now actually) and an CO analyzer too. I wouldn't trust my life with anyone at all, I do the analysis myself or nothing.

I wouldn't raise a stink about it but I'll make sure let them know what I think. I'll go out of my way to ask the dive op. for an analyzer first just to verify that they actually do or don't have it and then make my stand clear.

 

[Jayfarmlaw]

I have always tested my tanks. When diving with Aldora in Cozumel, their labels have always been spot on. Sometimes we test at the dock if they are short on testers, but most of the time there is a tester on the boat. I believe they use a membrane system and fill their own tanks so the room for error in trusting a chart and a tank monkey should diminished. In Cuba, we did not dive Nitrox but short fills and leaky tanks were common. I would not have dove Nitrox without a tester there. Roatan, Curacao, and California all had testers available. Sometimes they will hand you the tester, sometimes they will test it in front of you.

It takes less than 20 seconds to test a tank. You're not going to hold up anybody.

Other places I have tested at the shop or on the dock, but there has always been a way to test. I test mine and my wife's tanks, and if I am DM for our travel group, their tanks as well. At our age we appreciate Geezer Gas.

Should you buy a tester? Yes. Do you have to? No. The sensors have to be replaced and used to cost around $90 last time I checked. I'd rather use the shop tester.

Good luck, welcome to geezer gas diving.

Jay

 

[Diverlady13]

HELLO. I just got my NITROX certification. All went well. However, as my instructor was going through the training of testing my tank with the oxygen analyzer, she stressed over and over again how it's my responsibility to test the tank before each dive and to ensure that the proper labels are affixed to the tank (name, date, O2, etc)...She was very firm on these issues and I appreciated her passion for teaching...

OK, question. I recalled several months ago, I went to Cozumel to dive for a month. I was pretty new to diving and I dove with some pretty experienced, dive masters, instructors, etc...THEY ALL USED NITROX. (I didn't because I wasn't certified at that point)...But, I never saw any of them, EVER, test the tanks before the dives. I don't even recall seeing an O2 analyzer anywhere.

I dove the entire month with a reputable LDS, who I bet was pretty careful to test the tanks before setting up the dives...And of course, all dives went off without a hitch.

So...what gives? Is this one of those things where you train ONE WAY but perform real world functions ANOTHER WAY??? Should I invest in an O2 analyzer. When diving should I insist that I personally test my tank. Will I be holding up the whole operation?

OR...SHOULD I JUST GO ALONG WITH THE CROWD AND TRUST THAT THE LDS HAS DONE THE LEGWORK?

Thanks everyone for your help. ))

I don't think I'd just want to trust the mix. Anyone can make an error when they write down the percentage and without you watching the test, you really have no idea if the mix was actually tested or if someone took a shortcut. Even really great businesses can sometimes have an employee who doesn't do their job properly or who just gets lazy and/or makes assumptions.

Most of the OPs we've been diving with have had analyzers available. I would even note that almost every one of them had done the testing for us but with us watching. So basically the person doing the testing won't do it until you're ready to watch and note the numbers. Then they've had us fill out and sign the log. (We never filled out any logs in Mexico, but I don't care about their log - only about knowing for sure what the mix is.) Testing for the group might be due to dive ops not wanting someone to damage their analyzer, but I bet it's more to do (recently) with covid....only having one person handling the analyzer rather than passing it around. We did one dive earlier this year where the OP did not provide an analyzer, but we had a guide with us who brought along an analyzer specifically for our tanks. (This was a dive that required a guide.) After that, and asking about analyzers here on scubaboard, I bought my own analyzer and bring it along on dive trips. Lots of places still require that they test with their analyzer in front of us, but then I can also test with my own to verify the results if I feel it necessary.

 

[Marie13]

What about your local dive shops? I’ve gotten fills at places that analyze and require you to sign their log. Other shops analyze but don’t keep a log. One shop knew I had an analyzer at home and didn’t require me to analyze in the shop. I’m not sure if they have a log. This was a shop that knows me.

 

[loosenit2]

It only takes a few minutes for the gasses to diffuse: How Quickly Do Gases Mix?

i've gotten 2+% differences on day of fill and a few days later. I'll keep testing day of dives.

 

[wetb4igetinthewater]

What about your local dive shops? I’ve gotten fills at places that analyze and require you to sign their log. Other shops analyze but don’t keep a log. One shop knew I had an analyzer at home and didn’t require me to analyze in the shop. I’m not sure if they have a log. This was a shop that knows me.

If there's a mistake made in a foreign country that is most likely going to be your problem.

 

[lowwall]

i've gotten 2+% differences on day of fill and a few days later. I'll keep testing day of dives.

How soon after the fill was your first test?

I've been looking at this since I responded to your last post and while there's a lot of discussion, no one seems to have done the obvious and retested tanks every x minutes to see how long it takes to fully diffuse.

 

[Aviyes]

Everywhere I have dove, Caymans, Bonaire, Turks & Caicos, and Florida Keys it was standard practice to either test yourself or observe the testing. LOBs you are required to test and log after every fill and the DMs check the log was completed before divers are allowed in the water. Bonaire the tester was at the tank shack. You tested/logged th, then either took the tank or tagged it with analyzed % for dropoff at the resort shore dive location.