Discuss: gas analyzer before second Shearwater?

[Marie13]

Agreed.....but the steps before He (adv nitrox, DP etc) where there is no He.....analyzer is a must. Even rec nitrox an analyzer is highly recommended.

I’m doing the AN/DP/Helitrox combo.

 

[broncobowsher]

I’m doing the AN/DP/Helitrox combo.

How good is your gas source? Is there analyzer something you would own or do you question it?
Does your instructor want you to learn with cutting tables and making dive plans and backup plans? Or do they want to see you in a backup computer. It really can go either way for you. You are paying your instructor to instruct you, take there advise off what you get on the internet. But feel free to let us know what they want and more important why they want you setup that way.

Personally, at this point, I would lean more toward an analyzer. Why? Once you do your dive and still have a little gas left you can get it topped off with air for regular recreational diving. You can stop by any dive shop and get an air top off, but not every dive shop can analyze trimix. So to know what you have you will need your own analyzer.

 

[Marie13]

How good is your gas source? Is there analyzer something you would own or do you question it?
Does your instructor want you to learn with cutting tables and making dive plans and backup plans? Or do they want to see you in a backup computer. It really can go either way for you. You are paying your instructor to instruct you, take there advise off what you get on the internet. But feel free to let us know what they want and more important why they want you setup that way.

Personally, at this point, I would lean more toward an analyzer. Why? Once you do your dive and still have a little gas left you can get it topped off with air for regular recreational diving. You can stop by any dive shop and get an air top off, but not every dive shop can analyze trimix. So to know what you have you will need your own analyzer.

Instructor knows I’ll the run the Geo in gauge mode for backup. Has no issues with that. If I had two Perdix, he’d work with that, as well. Doesn’t require two tech computers for folks just starting out. First classroom session isn’t until February, but once you show you can do the math, he has you plan with MultiDeco. He suggested I download it and start getting familiar with it. I’ve had the iPhone app for months and run dives on it. I have the desktop version, but need to get more familiar with it. Instructor prefers desktop for additional functionality.

ETA: instructor hasn’t said anything about an analyzer. It came up in conversation with the friend and I’ve not had a chance to ask instructor about it yet.

 

[KenGordon]

I know many more people with O2 analysers than Shearwaters. If you have not moved on from diving air to best mix and sorting out minimising deco obligations then the whole ANDP thing seems like a bit of a big step.

For just ordinary Nitrox diving an analyser is a good idea. Once you start trans filling to top up random mixes, or getting air tops on yesterday afternoon’s rich fill you want an analyser. All that time diving with one multi-gas computer, such as a vyper, i300c or any mid level computer will work. Even with weak mix you will be ok, for my early trimix dives I was using a Helo2 with a Zoop backup, my buddy was using two Vyper Airs and everything came out lined up (except the Zoop of course, being single gas)

Shop/dive op/boat analysers fail. I have had to get a shop to analyse a J of 100% He before they’d believe me that their analyser was bust. Divesoft analyser O2 cells die eventually, analog ones sort of fade away.

I bought my o2 analyser when I began doing much Nitrox diving. The Divesoft He one was a Christmas present, I actually ordered it at the same time as a backup Shearwater. It is easier to get away without a helium analyser, but an O2 analyser is essential when you get serious.

Fancy computers are fine, but there really are better ways to spend money.

 

[cruisekingkris]

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 ?

 

[rddvet]

Perhaps if you're taking a hot fill with you, but most people, myself included, drop tanks off and pick them up at a later date where they have since cooled to room temp. But let's apply your theory to reality. It's 80 degrees where I'm at right now. Tanks baking in the sun on a boat will probably be warmer, yet the water is in the mid 60's. So if you're really going to be that pedantic you should soak your tanks in the water to get an accurate read out for the actual condition the gas will be in. You'll just need to have thick skin when everyone else on the boat razzes you. It's inconsequential, IMO, and if you have tech training you were likely taught to dive a little more conservatively giving yourself some buffer room for slight variances.

Nothing to do with heat. I'm specifically talking trimix that's been pp blended. It is not uncommon to analyze it off the final whip and then 3 days later it's significantly different. I've seen it from shops as well as in gas I've mixed myself. If I don't have a ton of 32 or air to top over the helium, you'll often get a high helium and low oxygen reading. For fun I've actually tested it and pp topped off a trimix tank and had to use very little air. Almost all helium. I didn't move the tank at all and took readings twice a day for 3 days. Directly after fill and later that day were very different. Next AM was a little different. It continued to vary slightly until day 3. Gasses don't always mix evenly or quickly.

I am a huge proponent of multiple checks after well trained tech divers have died because they thought they had something in their tanks other than they did. The thread is specifically about technical gases, which to me typically include helium so that was my example as to why a check at the shop after filling could be off. It's probably not enough to kill you, but what's wrong with checking again later?

 

[rddvet]

It’s not necessary to have a Helium analyzer to dive mix. Most just analyze the O2 content. The actual HE % isn’t critical.

Most just analyze O2? Where you get that from.
It's possible to extrapolate He content based on O2 content. That definitely doesn't mean it's smart or what "most" do.
I really hope "most" don't do that. I'll add this to my list of questions for potential tech buddies.

 

[Marie13]

Nothing to do with heat. I'm specifically talking trimix that's been pp blended. It is not uncommon to analyze it off the final whip and then 3 days later it's significantly different. I've seen it from shops as well as in gas I've mixed myself. If I don't have a ton of 32 or air to top over the helium, you'll often get a high helium and low oxygen reading. For fun I've actually tested it and pp topped off a trimix tank and had to use very little air. Almost all helium. I didn't move the tank at all and took readings twice a day for 3 days. Directly after fill and later that day were very different. Next AM was a little different. It continued to vary slightly until day 3. Gasses don't always mix evenly or quickly.

I am a huge proponent of multiple checks after well trained tech divers have died because they thought they had something in their tanks other than they did. The thread is specifically about technical gases, which to me typically include helium so that was my example as to why a check at the shop after filling could be off. It's probably not enough to kill you, but what's wrong with checking again later?

My shop (DRIS) doesn’t PP unless you want a mix with more than 32%. They use the banked 32% to mix and top with air. This is why my doubles don’t need to be O2 cleaned. I specifically asked. The only cylinder I currently need to keep O2 cleaned is deco bottle.

 

[_Ralph]

At the very least, a trimix analyzer on-site as a team resource. They are costly (a shearwater is too, but it ‘does’ more and is used longer)

In a perfect world you’d have your own... as well as everything else you’d ever want with free helium fills, but we gotta make do with what we can...

_R

 

[_Ralph]

Which O2 analyzer is $100?

An O2 cell, connector and hookup wires to a multimeter will get you an analyzer .... roughly $100, have any CCR buddies, probably can get a used O2 cell for free.

_R