nitrox analyzing question

[PerroneFord]

By the way, at the shops that I have been to that blend trimix, the helium is connected to whips too short to reach where the nitrox fills are done. So to get the helium, you must disconnect the tank, and physically carry it somehwere else to get the helium. And yet, those guys analyze just the same.

If you don't analyze, you have NO IDEA what's in that tank. Air, Nitrox, oxygen, Helium, or anything else. Which is why we label NOTHING at our shop. And we do not answer the question, "What did you fill this with?" You get handed an analyzer and a sticker.

 

[Charlie99]

I do not attach a regulator to a tank I have not analyzed. Period. I analyze the tank EVEN WHEN I FILL IT MYSELF.

Do you ANALYZE it or do you merely check oxygen content?

:1poke: Do you know how much helium is in it? Do you know how much carbon monoxide and oil is in it?

 

[Web Monkey]

How do you know it's air?

That's another trick question.

You never know if it's air, unless you have compared the O2 content against air.

Even if there's no air reference tank, you can still wave the O2 sensor around in free air to get a pretty close reasing, then check the tank.

It will be off by a percent or so, but you'll have a really good idea if you're diving with 21% (or less!), 32%, 50% or 80%.

I stopped trusting everybody right after my Tobermory incident.

The line between obsessive and careful seems to be a fine one.

Terry

 

[Web Monkey]

IMHO, if you can't trust a shop to know whether it is air or not then you'd definitely need to go to another shop.

Why trust anybody? People screw up. Even really nice people who are usually careful.

Maybe the tank guy had a rough night and thought your tank belonged to Mr. 260' trimix diver.

What's the harm in analyzing before you dive?

You can chase your tail all day by playing the how do you know, but, what if game.

There's no game. You check the analyzer with room air or known tank air, then check your tank.

Terry

 

[cummings66]

I bought my own analyzer, I feel better knowing that my analyzer and theirs both agree on a value that's close. Sometimes they're off a bit, but normally pretty dang close.

I look at it this way, how much is my life worth? An analyzer is cheap in comparison and I for one intend to be here the day my daughter grows up and does those big firsts.

 

[Scared Silly]

While in Utila the place we were diving got their nitrox from their sister shop. Once they realized we had our own analyzer the tanks just showed up. We analyzed them and off we went. This was instead of walking over to the sister shop checking tanks marking them the night before, and then hoping that they were in the same condition the next morning.

I addition to my our analyzer I also bring my own pressure guage so that I can also check the pressure before heading out. Nothing worse than a 90 minute boat ride for a three tank dive only to find out that the cylinders are at 2500 psi and not 3000psi.

 

[TSandM]

It's an interesting question about analyzing just O2. I get my tanks filled in a tech shop that fills helium. I dive 32% all the time, thus I analyze every tank when I pick it up. But it never occurred to me to think about whether there might be helium in a tank. I guess I assume the stuff is so expensive that the shop itself would have a good system for making sure I didn't get helium I didn't pay for But in the shop where I did my class last weekend, the helium is just a turn of a valve away.

Does ANYBODY here analyze Nitrox tanks for helium content? Still feels like overkill to me.

 

[PerroneFord]

I asked my instructor the same thing when I took Adv Nitrox. For me, two things work. I am in possession of my tanks nearly all the time. If I am doing a dive where helium would affect my ascent profile, AND the tanks were out of my possession, I will analyze for helium. Most of the dives I do helium would not affect my ascent profile, and on the rare occasion that I am doing a planned deco dive, I either fill my own tanks, or am present when they are filled. Our shop also has physical constraints such that you cannot get helium without taking the tanks to a different location. easy and smart in my opinion.

 

[TSandM]

Of course, I also breathe off my regulators during my pre-dive check and while I put my fins on, and if there were helium in the mix, I'd find that out then . . . My Rec Triox instructor was telling us that, after enough experience, you can almost estimate the percentage helium in the mix by just how Donald Duck-ish your voice becomes

 

[PerroneFord]

Be careful. If you breathe a bottom mix suitable for Wakulla, Eagles Nest, or other spots, you'll pass out on the surface. Analyzing is safer.