Is purchasing an analyzer really necessary?

[halocline]

It's not a question of analyzing or not analyzing a mix, you have to analyze it and you have to sign off on the analysis, at least at the shop I got nitrox certified from, and it's in the Caribbean. Since you can, and should, calibrate the nitrox analyzer by testing a tank of air immediately before using it on the tank in question, I see no real benefit to having your own. How would you know, other than the calibration, whether the one you own is any more accurate than the one at the shop?

 

[Web Monkey]

My question is really for when I travel to foreign countries in the Caribbean and Asia. If I'm using EANx and getting my fills from a dive shop in a foreign country, should having my own analyzer be a must or can I trust the dive shop's analyzers?

You decide.

I was in a dive shop in Tobermory. I won't name the shop, but if you can get your boat up to ramming speed while docking, you'll land on their front porch

When I went to pick up my tank, the tank-girl said "You have to watch me analyze this". So I said "OK".

She proceeds to hook up my tank, then crank the zero-adjust on the analyzer until it says "32", then looks at me and says "See? 32%"

I said that the "zero-adjust was for calibrating it against a known gas like air or O2, not to make it match what was supposed to be in the tank". She was not impressed and gave me the tank, which I put in the car and took home. (the weather had turned).

Right after that I bought my own analyzer.

With the proliferation of all sorts of mixed gases with various min and max depths, I wouldn't dream of diving a tank I hadn't personally analyzed.

And this was in Canada. Somewhere else, where the fill person might not have any real idea what he's doing, it would be even more important. In fact a CO monitor would be a good idea too. See the Bannai Adventurer thread here.

Terry

 

[DandyDon]

I imagine that any shop that provides Nitrox will have a tester, even tho not all will require you to analyze. It's your option, as long as you sign for it - but of course you should. I bought my tester after a trip to Roatan and a tester I didn't like, but now most have the same one I use - so I seldom expose the sensor on mine. The CO tester cost me 1/3 as much and is used on every tank now. DAN admits they don't know how many "drownings" were caused by bad air.

 

[pasley]

Do you need your own analyzer? I don't know you decide. This quote is from another board where the diver was diving Nitrox and the nitrox was delivered every morning and the blender had "already checked it".

Cozumel Nitrox - The Dive Matrix Forums

The kicker came this morning as my "analyzer monitor" watched me analyze one of their "32" tanks as 41.5%.

 

[vladimir]

Sometimes on a liveaboard it comes in handy because the other 11 divers are sharing the one analyzer the boat has made available.

 

[Hickdive]

Are the DMs diving nitrox? Are they using the boat's analyser?

If yes to both then I'd be happy using their analyser. The DMs are unlikely to risk their own necks on a dodgy analyser.

However, I wouldn't ever take anyone's word for what's in a cylinder. Either I analyse it or I watch them analyse it for me and see the result for myself.

BTW I wouldn't normally calibrate with a cylinder of 'air' since logically I don't know that it is air. Either calibrate with atmospheric air or with the oxygen supply cylinder.

The only time I'd consider calibrating from a cylinder of 'air' would be if the humidity was high enough to throw off calibrating to the atmosphere and then I'd have to be absolutely certain that it was just air in the tank I was calibrating from.

 

[DandyDon]

I doubt that the majority of Nitrox divers own an analyzer. Most use the one furnished by the provider. The sensor life on mine is projected to be 3 years, so I guess I need to think about doing that @ $140 or so.

BTW I wouldn't normally calibrate with a cylinder of 'air' since logically I don't know that it is air. Either calibrate with atmospheric air or with the oxygen supply cylinder.

The only time I'd consider calibrating from a cylinder of 'air' would be if the humidity was high enough to throw off calibrating to the atmosphere and then I'd have to be absolutely certain that it was just air in the tank I was calibrating from.

Good point. I think I was taught to use an air tank to calibrate, but nowadays just wave it in the air. I wonder how much the high humidity at dive locations affects it?

 

[Hickdive]

I doubt that the majority of Nitrox divers own an analyzer. Most use the one furnished by the provider. The sensor life on mine is projected to be 3 years, so I guess I need to think about doing that @ $140 or so.

Good point. I think I was taught to use an air tank to calibrate, but nowadays just wave it in the air. I wonder how much the high humidity at dive locations affects it?

The analox compensation chart is on page 12 of this .pdf

http://www.analox.net/site/content_manuals/Analox_101D2_user_manual.pdf

As can be seen. for example, at 80% humidity and 80F you should be calibrating to 20.3 not 20.9 if using atmospheric air. If you use the dry air from a cylinder you don't need to make this adjustment, provided you know it is air in the cylinder.

 

[40Fathoms]

I don't have my own analyzer, so I've always used the shop's of where ever I was diving. I haven't had a problem with this. I've dived EANx in Western Europe only, and I think I was to go to for instance Asia or Africa, I'd purchase and bring my own. I've had friends who have had experiences with dive operations in those locations that were less than optimal. So my answer would be no, you don't need your own if you diving out of a dive shop you trust and that have their own analyzer. But in some situations, you might want to have the piece of mind of having your own.

 

[Scott M]

It's not a question of analyzing or not analyzing a mix, you have to analyze it and you have to sign off on the analysis, at least at the shop I got nitrox certified from, and it's in the Caribbean. Since you can, and should, calibrate the nitrox analyzer by testing a tank of air immediately before using it on the tank in question, I see no real benefit to having your own. How would you know, other than the calibration, whether the one you own is any more accurate than the one at the shop?

Matt, I carry my own analizer everywhere I go if I am breathing Nitrox but I have never used a tank of air to calibrate it. I usualy just wave it slowly in the surrounding air to set it then test the mix. Is this a bad idea?