Checking Nitrox mix on vacation?

[BEM]

I have a few questions about diving Nitrox when on vacation down south, as I will be doing next January.

1. If you have contracted to dive Nitrox, do you check the mix to be sure of what you will be using?
2. If you have checked your tanks, how do you know that you will be getting the same tank when you’re diving? The first tank may be easy (as you can keep an eye on the gear), but when on your break the crew set it up out of eyesight – how do you know if you get the tank you verified and do you care?
3. If you got a different tank on your dives – what would you do?

 

[AliKat]

Are you certified to dive Nitrox?? If so, you should no that the diver using the tank must always check the O2 content personally before using the tank.

Tell the dive operator not to touch your stuff...period!!! If you find they have set it up, and it is not the same tank (most rentals will have numbers, note the number on the tank), and they don't have the device on board to re-check, I wouldn't dive Nitrox that dive!

I am certifed, but rarely dive Nitrox, however, NO ONE sets my gear up but me!! For one, I usually take my own gear (except for tanks and weights) and no one is going to take better care of it than me. And two, I have to breath it, so I will be the one to set it up. When I go on trips where set up is part of the deal, I just let them know I will not be using that particular service.

 

[Spectre]

Originally posted by BEM
1. If you have contracted to dive Nitrox, do you check the mix to be sure of what you will be using?

You are going to have to sign for the tanks. If they've analysed it and stickered it, insist on witnessing the analysis or doing it yourself. Don't sign before you see the results of the analysis.

2. If you have checked your tanks, how do you know that you will be getting the same tank when you’re diving?

A sticker will be put on the tank with the EAN percentage and the MOD. Either 1) fill out your own sticker so that you know your handwriting, or 2) write your name on the sticker if they wrote it out for you.

3. If you got a different tank on your dives – what would you do?

Don't dive it, and find the tank that you personally analysed or witnessed analysis.

 

[BEM]

Yes, I am Nitrox certified and ALWAYS personally check the mix and sign for it up here in Canada.

I haven't used nitrox in the Caribbean and was just wondering what other divers do to make sure they are diving safely.

I had planned, and will, insist on checking the mix myself, but on my last trip (Caribbean), the tanks were not marked and I wondered how I would know if the tank I got was the tank I checked. Everyone was diving air.

I am assuming that the operators would have all nitrox tank stickered, but I would only be initially checking my tanks.

If you aren't sure, would you dive as an air tank (but keep your depth shallow - worst case - so you don't go over 1.4 assuming your tank has 40% nitrox)

Thanks for the input.

 

[Spectre]

Originally posted by BEM
I had planned, and will, insist on checking the mix myself, but on my last trip (Caribbean), the tanks were not marked and I wondered how I would know if the tank I got was the tank I checked. Everyone was diving air.

Take a roll of masking tape. Mark your tanks with your EAN percentage and your MOD.

If you aren't sure, would you dive as an air tank (but keep your depth shallow - worst case - so you don't go over 1.4 assuming your tank has 40% nitrox)

What about the other guy?

If you don't know what gas your breathing, don't dive... in fact, if you loose your tank, make it _known_ it's missing. 'cause if you've got someone elses tank, that means someone else has your nitrox tank, and _they_ will end up getting themselves killed, and it's your fault.

Mark your tanks.

 

[miked]

BEM,
Alikat and Spectre said it all. I, too, set up my own gear. Spectre's post and experience sounds identical to mine.
( I have used Nitrox in Bermuda, Bahamas, Cozumel, Aruba, Grand Cayman, but even in the same locale, individual dive operations may work differently)
First, be certified, and have the correct computer. Second, analyze the contents yourself (and don't hesitate to ask how to use the analyzer-each type has its own peculiarities). Put your name on the tank sticker, and keep an eye on where they ("2 tank dive") are placed on the boat. If the DM/ Captain on the boat is not the person who helped you with the analysis, let him/her know that you'll be needing "these particular tank(s)" for your dives.
If, after all that, you somehow wind up with a "different" tank- ask the crew to look for "your" tank. If, for some reason, it cannot be found, decide whether to dive with the current tank or not, but don't forget to reset your computer [or recalculate w/tables].
BTW if the "incorrect tank is not air, but some EANx mix, reanalyze it, or ask for an air tank.

Remember, it is YOU who are breathing this mix, and will have to suffer the possible consequences (w/r/t O2 tox/ DCI), if you are planning a dive based on a "mixture" different than what you are expecting.
Hope this has been helpful,
Good luck,
Mike


ps: BEM, your second post addressed some of my comments- sorry about having "boxing gloves on" typing skills


Edited to add:
Jeff got it too!!! Man I am SLOW on the keyboard!!!

 

[BEM]

Good advice and much appreciated. I just wanted to know what other divers do and a few tips and gain knowledge from more experienced divers.

Safety is critical and that's the reason I took the Rescue Diver Course and upgraded my, and my wife's regs to Apeks ATX 200s, from our lower grade (first purchase) regs.

Once again thanks.

 

[scubatomwetzel]

You should have your own analyser. If not, do not dive NITROX!!
Have it checked periodically with another. The should be within 1% +/-.

scubatomwetzel

 

[roakey]

If you don’t have an analyzer yet, the best price performance you’ll find is the “El Cheapo”

http://www.oxycheq.com/el_cheapo_II.html

As long as you’re handy with a soldering iron, building it yourself is the way to go. You might be able to do it a tad cheaper if you try and pull the parts together on your own, but getting the kit is far easier.

I would not recommend the “Home builders Bible for Oxygen Analyzers” that you’ll find on that page, though. If you’re interested in building one from scratch, get the “Oxygen Hacker’s Companion” from http://www.airspeedpress.com/ which will cover building analyzers as well as a whole bunch more of interesting stuff like tank tumbling, gas mixing and more.

Roak

 

[boydski]

I have been on several trips to the Caribbean while diving Nitrox and the operator did not have an Oxygen Analyzer available. This has happened more than once on a Live-aboard. I take my El Cheapo II with me, which has an adaptor that fits my LP Inflator hose, so once the tank is hooked up to my reg, it's easy to connect the hose to the meter and verify the gas. Once checked, I set my Computer ( which is set to use the same mix and not revert to air ).

This is quick and easy to do. I keep the Analyzer is a really small Pelican Case so it survives the rigors of getting knocked around on the boat and stays dry.

If you are at all handy with a soldering iron, it's fairly easy to make the meter.

My experiance has been that the tanks often have LESS oxygen in them than marked. For Example, I've seen several cylinders marked 32 percent that really only had 29 or 30.

Boydski