Discuss: gas analyzer before second Shearwater?

[girlwithbigtanks]

I bought an O2 analyzer the first time someone packed tanks for me and forgot to bring the shop one. I was supplied 32% for teaching, my coworkers forgot. This is way before I learned to technical dive. I always analyze my 02 before ever dive, even when I do my own fills. Way more important than 2 technical computers.

 

[_Ralph]

Why is it necessary to analyze your tanks on your own if “you” analyzed it at the shop when you picked it up after it was filled. My shop has a great set up for analyzing your tank when you pick them up. I don’t see it necessary to analyze a second time. I mark my tanks with mix, pressure and MOD (not using helium)

Why would I need an analyzer ?

Same reasons why you do a gear match/buddy check while getting ready to dive, to make sure.

If I show up on any dive and there’s not an analysis sticker with TODAYS date on it, i’m Gonna question what is in that tank. Your tank, my tank, someone else’s tank.

It’s not your gas in your tank, it’s mine (for OC diving) and similarly, my tank has your gas..

_R

 

[CuzzA]

Why is it necessary to analyze your tanks on your own if “you” analyzed it at the shop when you picked it up after it was filled. My shop has a great set up for analyzing your tank when you pick them up. I don’t see it necessary to analyze a second time. I mark my tanks with mix, pressure and MOD (not using helium)

Why would I need an analyzer ?

You don't have to. Millions of EANx dives are safely conducted every year without incident and I'd venture to guess many EANx divers don't own an analyzer since any shop filling EANx will be providing their analyzer. ScubaBoard will be the exception on many topics. The only incidents I've personally heard where someone has taken a CNS hit is when they did not analyze their gas or switched to the wrong mix during the dive. Considering ppo2 recomended limits were lowered again to 1.4 it is even less likely to happen to someone even if the o2 is slightly higher than believed.

There's definitely benefits as mentioned to owning an analyzer. If you're whipping tanks with different mixes on location that would be the biggest one for me. But, like I said, if a shop has an analyzer and you request 32% and the analyses reads 32%, I'm diving the tank at 32%. I'm not a stats guy, but I'd say the odds of that analyses being fatally and unrecognizablely off are extremely low.

 

[NAM001]

When it comes to analyzers I always take my own. too many times the shop has only one working if not only one at all. That means there is no second check as to whether the O2 meter is accurate. using your meter will point out the difference if one exists and you go form there. COZ gave me a tank of 32 by their meter and mine read 28. when I got home my meter was accurate when checked with others. When I am out with others I have my tank checked with my meter and others to validate the probably accuracy of bot mine and others meters.

 

[NAM001]

You don't have to. Millions of EANx dives are safely conducted every year without incident and I'd venture to guess many EANx divers don't own an analyzer since any shop filling EANx will be providing their analyzer. ScubaBoard will be the exception on many topics. The only incidents I've personally heard where someone has taken a CNS hit is when they did not analyze their gas or switched to the wrong mix during the dive. Considering ppo2 recomended limits were lowered again to 1.4 it is even less likely to happen to someone even if the o2 is slightly higher than believed.

There's definitely benefits as mentioned to owning an analyzer. If you're whipping tanks with different mixes on location that would be the biggest one for me. But, like I said, if a shop has an analyzer and you request 32% and the analyses reads 32%, I'm diving the tank at 32%. I'm not a stats guy, but I'd say the odds of that analyses being fatally and unrecognizablely off are extremely low.

I have done trust me dives on EAN only after checking for accuracy of a couple of tanks and inspecting their set up. If PP blending there is no trust. If filling from banked 32 and some one says their tank is good then mine is good also. Especially if I am not going to MOD.

 

[kensuf]

An O2 analyzer is inexpensive insurance that you will know what you're breathing before you get in the water. Just because you analyzed and labeled a bottle at the shop does not mean you won't screw up later; a friend of mine died in 2001 because he misread a gas analysis label from a bottle he had filled six months earlier.

Breathing too much (or too little) oxygen is what causes fatalities, it's always a good idea to at least verify the oxygen content before you put a reg on the bottle, and a simple analyzer isn't that expensive. And while I personally own a fancy schmancy trimix analyzer, I'm in the camp that you can simply use an O2 analyzer for your final verification even if you're diving trimix.

Here's why:

There should be at least two times you analyze your gas.

1. When it's filled at the shop. If you're getting a trimix fill, you'll do your initial analysis using their trimix analyzer and label the contents accordingly (and don't forget to write it in the shop log!!!)

2. Before you put a regulator on the cylinder when you're preparing to go diving. This is the VERIFICATION of what you expect to have. You should already have an idea of what is in the cylinder (because you analyzed and labeled it at the shop in step 1). If the O2 % is close to/similar to what your label says, your helium content is going to be pretty darn close. If your O2 % is wildly off, YOU HAVE A PROBLEM THAT NEEDS FIXING. While a trimix analyzer would allow you to figure out what gas you have in your cylinders, the odds of you being able to fix the mix at your house are probably NIL for the majority of us, so you're going to be headed to the shop anyway.

O2 analyzer's aren't that expensive. If you have a little bit of soldering ability, an El Cheapo DIY O2 Analyzer kit can be purchased for $110. That includes a sensor.

OxyCheq - EL Cheapo II Analyzer Kit

If you're truly cheap, you can use a voltmeter, calculator, and O2 cell to analyze your gas -- I did this for the first three years I was cavediving. But a good voltmeter, calculator and cell is probably more expensive than the el cheapo.

 

[kensuf]

I have done trust me dives on EAN only after checking for accuracy of a couple of tanks and inspecting their set up. If PP blending there is no trust. If filling from banked 32 and some one says their tank is good then mine is good also. Especially if I am not going to MOD.

What if the cylinders started with some other gas in them but were not labeled before you filled from the 32% banks?

True story.. Six years ago I was teaching an AN/DP course to a guy that worked at a scientific diving program. He was the equipment manager, the dive locker had a few sets of doubles. Their fill station could only fill air, they didn't have the ability to mix nitrox. I made the student analyze his doubles, the analyzer came out to 26%. He was convinced my analyzer was wrong, we calibrated it against a couple of other bottles and confirmed the analyzer was correct.

It turned out another staff member had checked out a set of doubles, got them filled with 32% so he could go cave diving, but didn't label the doubles (or tell anyone).

Bottom line, you always need to analyze your tanks.

 

[Caveeagle]

Ken, your example is why I think Nitrox should be taught along with OW at this point. Especially around our neck of the woods, you should never assume the contents of a tank. Thankfully, few people who are renting tanks are diving below the MOD of 32%, it I have seen some pretty sketchy things happen in the back of pickups with fill whips!

What if the cylinders started with some other gas in them but were not labeled before you filled from the 32% banks?

True story.. Six years ago I was teaching an AN/DP course to a guy that worked at a scientific diving program. He was the equipment manager, the dive locker had a few sets of doubles. Their fill station could only fill air, they didn't have the ability to mix nitrox. I made the student analyze his doubles, the analyzer came out to 26%. He was convinced my analyzer was wrong, we calibrated it against a couple of other bottles and confirmed the analyzer was correct.

It turned out another staff member had checked out a set of doubles, got them filled with 32% so he could go cave diving, but didn't label the doubles (or tell anyone).

Bottom line, you always need to analyze your tanks.

 

[Wookie]

If you're not filling your own tanks what's the point? My shop has two AI analyzers. I can't see a practical reason to buy one when you should be analyzing and marking your tanks at the shop. If you don't trust your shop's anaylizer, you might be better off finding a different shop, because what else are they neglecting at the fill station?

I agree with Cuzza that if you are getting fills at the shop, dropping empties at the shop, and picking up the fulls, the shops analyzer is sufficient.

OTOH, I also believe that practically no one does this except a very few. Folks expect to be met at the boat with their tanks, and it is incumbent on the diver to analyze his or her own gas. I do not lend out my 1000$ analyzer on the boat. So every diver should have their own analyzer for the gas they dive.

And who needs 2 computers?

 

[J-Vo]

Which O2 analyzer is $100?

Made it myself. Or you can buy a kit from Oxycheck for a few bucks more($120?).