Nitrox users-- do you own an O2 analyzer/meter?

[Lynn CA]

Dec 26th I was on a dive boat in Monterey bay. About 10 of the 22 divers had requested NITROX, some 32% fills, some 36%. The boat's analyser wouldn't calibrate. The tanks weren't labeled which were 32 & which were 36, so only by using our analyser did we discover that the tanks we were told to use were 36%, not the 32% we had requested. Some who had requested 36%, had the 32% tanks. As our dives that day were below 100 feet, it made a difference. I wouldn't have dived that day if I hadn't had my analyser.

Also I have been on 2 liveaboards and usedeNITROX. I bought my analyser after the 1st liveaboard, because all who used NITROX had to wait to use the one analyser on the boat, causing a delay of almost 20 minutes for the last user, to be able to get in the water.

I was so glad to have the analyser on the 2nd trip, and so avaoid the same kind of delay.

We use 2 dive computers, one set to the NITROX mix to track CNS o2 toxicity, and the other set to air. We dive to the one set to air, for a safety margin, and monitor the other to make sure that if we do 4 or 5 deep dives a day on the liveaboard we don't get too much o2 exposure.

 

[Vie]

Has anyone used a Delta P VR3 with the analyser option? Any comments? Do you prefer this to having a separate analyser?

 

[jerryn]

Three reasons to have your own

Others are not always right
Others are not always available
Sometimes (often?) you have to watch the owner do the analysis, you are not allowed to do it yourself.

Small investment for the comfort of knowing what you are breathing.

Jerry

 

[JS1scuba]

Dec 26th I was on a dive boat in Monterey bay. About 10 of the 22 divers had requested NITROX, some 32% fills, some 36%. The boat's analyser wouldn't calibrate. The tanks weren't labeled which were 32 & which were 36, so only by using our analyser did we discover that the tanks we were told to use were 36%, not the 32% we had requested. Some who had requested 36%, had the 32% tanks. As our dives that day were below 100 feet, it made a difference. I wouldn't have dived that day if I hadn't had my analyser.

Also I have been on 2 liveaboards and usedeNITROX. I bought my analyser after the 1st liveaboard, because all who used NITROX had to wait to use the one analyser on the boat, causing a delay of almost 20 minutes for the last user, to be able to get in the water.

I was so glad to have the analyser on the 2nd trip, and so avaoid the same kind of delay.

Dear Lynn,

Thanks for your report. I have a few questions.

1. What was the response from the dive boat when you told them thier nitrox service did not meet with industry specifications for nitrox cylinder delivery?

2. What were the options provided by the boat for analyzing the gas had you not had your own analyser?

3. Based on your experience with this charter do you plan to always carry an analyzer with you ?

4. If this was a TDI facility would you be kind enough to PM me so i can contact them as I am the TDI Regional Manager for California. I would like to ensure that they get back on track with proper gas delivery.

Thanks

 

[Dive-aholic]

Sometimes (often?) you have to watch the owner do the analysis, you are not allowed to do it yourself.

If that's the case, you shouldn't be getting nitrox from there.

 

[nategasser]

One can even argue that the added safety margin with nitrox is only theoretical, but I am sure I will get flamed on that one. If it exists, it is only fractional. The fact is, from what I have read and learned about nitrox, the same amount of people get bent using nitrox on nitrox tables as get bent on air using air tables.

My understanding is that the safety margin only comes from diving Nitrox using air tables/computer. Which certainly makes sense.

 

[JS1scuba]

My understanding is that the safety margin only comes from diving Nitrox using air tables/computer. Which certainly makes sense.

That's not entirely the case. Using EAN will provide a significantly longer no-stop limit. However if you are not taking advantage of that entire no-stop time due to limited gas supply (single tanks) by default you end up with a better decompresssion advantage for the same dive had you dont it only with air.

If you run the no-stop limit to its end (providing you have sufficent gas supply) it has the same decompression "risk" as if you had run the dive to an air-no-stop limit.

Where the big advantage comes in on single tank diving is shorter surface intervals, and more repetitive dives in a series of dives.

Regards,

 

[Chivas]

I'd NEVER leave home without mine. It is my life, my responsibility, and noone to blame if something goes haywire. For a couple hundred bucks I look at it as cheap life insurance!!

 

[Damselfish]

I originally voted "don't see the need" on this as I've never had a problem having a good one available. But I just came back from a trip where with one op there was one analyzer for too many people and it wasn't working very well. And another where they didn't seem inclined to supply one until we insisted, we were supposed to trust their labels. Now I'm thinking about it. I figure I've done about 150 dives on Nitrox and recall at least 2 major surprises (like 39 when expecting 32, 25 when expecting 32.)

 

[Padipro]

I built my own several years ago from parts purchased right off the internet and not in any kind of kit (you can get the schematic and parts list off several web sites) for less then $150. It's just as accurate as any name brand unit and it's always in my bag. Even thought the shop checks the tanks after mixing I ALWAYS check them again when I get home and relable them just to make sure. It's a small investment of time and money that has come in handy more times then I can count. IMO an O2 analyzer is a piece of equipment every nitrox diver should have if at all possible.