Should I buy a nitrox (O2) analyzer?

[boulderjohn]

Not sure how common this is, since I have only been on one dive boat, but I did the advanced and Nitrox courses about a month ago. The boat we were on did not pass around an O2 analyzer or even have the tanks labeled. The captain just carried your 2 tanks on board and said "31% and 32%" and that was it.

No one on the boat seemed to mind, but me being new to Nitrox felt like it was a little too casual. I never had any plans to buy an analyzer until then.

How common is it? I have never seen it, and I would not use an operator like that again.

But NEVER NEVER NEVER trust any oxygen analyzer other than your own.

A couple years ago I was testing fills I had made myself earlier and the O2 levels for both trimix and nitrox fills were not what I expected them to be. Knowing I am not above making mixing mistakes (partial pressure), I was in something of a quandary. Fortunately, someone else had a trimix analyzer, and he got very different readings from mine. My O2 cell was only 2 months old, and it had previously worked fine. To make a long story short, the new O2 cell in my analyzer was defective. It had worked just fine for awhile, then it had failed. At that point, I was seeing only the beginning of the failure, when I had no reason to question it other than the fact it was not what I expected. Before long its defect became obvious.

 

[BRT]

How common is it? I have never seen it, and I would not use an operator like that again.

A couple years ago I was testing fills I had made myself earlier and the O2 levels for both trimix and nitrox fills were not what I expected them to be. Knowing I am not above making mixing mistakes (partial pressure), I was in something of a quandary. Fortunately, someone else had a trimix analyzer, and he got very different readings from mine. My O2 cell was only 2 months old, and it had previously worked fine. To make a long story short, the new O2 cell in my analyzer was defective. It had worked just fine for awhile, then it had failed. At that point, I was seeing only the beginning of the failure, when I had no reason to question it other than the fact it was not what I expected. Before long its defect became obvious.

We dove with some well known dive ops this year. None of them had testers on the boat.

Edit. One of them did but it sometimes showed 9% and other times a reasonable figure.

 

[KenGordon]

I realize this is the basic forum. But NEVER NEVER NEVER trust any oxygen analyzer other than your own. Too many divers with bad outcomes breathing the wrong gas mix that somebody else analyzed or didn’t calibrate correctly. One of the responsibilities of breathing a gas other than air is to own and use your analyzer.

You shouldn’t really trust your own analyser either. Eventually analyser cells die. Some analysers time out and force a change but mostly they just decline gently. Unless you can test yours against against 100% you are just hoping. Normally though you are only a second opinion and if the mix measures to an unexpected value you need to figure out why.

 

[Diverlady13]

It sort of does. O2 cells usually start failing by not being able to deliver maximum voltage, and then it deteriorates. So an almost spent cell may well be able to deliver a proper signal for 32% while not being able to deliver a proper signal for 80% or 100%. Problem is, when do you detect that it can't deliver a proper signal for 32%? So when it starts to fail, better replace it.


Well, what's your question, then? Go and buy another gadget. It's gonna be fun.

Ha! I guess you're right.

 

[Centrals]

What ever you choose to do just make sure you analyse the nitrox tank yourself. Trust NO label.

 

[yle]

I hope this is posted in the correct place, but if not please do move this thread.

Wondering if I should be purchasing an analyzer for my husband (dive buddy) and myself or if it's unnecessary and we should just be using the shop's or boat's analyzer.

Money isn't the issue. I just don't have a feel yet for if there is a great benefit to having our own or if it's just a hassle to have one more thing to carry on the plane.

Opinions?

If money isn't an issue then definitely buy an analyzer. I bring mine with me on trips just for the reason you're describing... some dive ops, especially outside of the US, do not have analyzers on board and simply deliver a "nitrox" tank for you to use. They really don't understand why you wouldn't blindly trust them (I've found a couple mis-labeled in the past... people make mistakes.)

The analyzer I have is likely the most popular one on the market (the Analox you mentioned above), and I think it runs about $300. The O2 sensor has to be replaced every 2 to 3 years, and the last time I replaced mine it cost $130. So if you analyze 30 tanks a year, the cost of the sensor will be a little less than $1 per tank. If you analyze more, the cost per tank drops. Since you're usually paying $10 to $15 per nitrox tank anyway, the cost of replacing the sensor, at .50 to 1.00 per tank, is a rounding error compared to the cost of the nitrox tank.

As for extra baggage while you travel... it's a handheld device, hardly takes up any room in your bag.

Hope this was a useful opinion!

 

[yle]

There were so many people stuffed onto the boat and the crew was rushing people into the water. It was a bit chaotic with so many people needing to analyze their cylinders and trying to get their gear set up with a very short ride to the reef. At least that trip taught us that our preference is for smaller ops generally or those that offer more help and less shrieking to "get in the water!!!". (I will get in the water when I am satisfied my gear is as it should be and not because someone is screaming at me to hurry up and crawl over the guys in the dry suits because the boat left late because a crew member overslept.)

Holy smokes... I have never been on a dive boat like this. Maybe you could leave a TA or similar review to warn other divers away. A crew treating divers like that is not only rude, it also suggests they are incompetent and would be incapable of effectively responding to an emergency.

 

[Diverlady13]

If money isn't an issue then definitely buy an analyzer. I bring mine with me on trips just for the reason you're describing... some dive ops, especially outside of the US, do not have analyzers on board and simply deliver a "nitrox" tank for you to use. They really don't understand why you wouldn't blindly trust them (I've found a couple mis-labeled in the past... people make mistakes.)

The analyzer I have is likely the most popular one on the market (the Analox you mentioned above), and I think it runs about $300. The O2 sensor has to be replaced every 2 to 3 years, and the last time I replaced mine it cost $130. So if you analyze 30 tanks a year, the cost of the sensor will be a little less than $1 per tank. If you analyze more, the cost per tank drops. Since you're usually paying $10 to $15 per nitrox tank anyway, the cost of replacing the sensor, at .50 to 1.00 per tank, is a rounding error compared to the cost of the nitrox tank.

As for extra baggage while you travel... it's a handheld device, hardly takes up any room in your bag.

Hope this was a useful opinion!

Thank you. Yes...your post was very useful and informative! I will definitely be buying an analyzer. Everyone has been so helpful and I've learned quite a lot here. We'll definitely be analyzing more than 30 tanks per year. If I can get an analyzer in time for our trip next week, we'll be analyzing well more than that on our upcoming trip.

 

[Diverlady13]

Holy smokes... I have never been on a dive boat like this. Maybe you could leave a TA or similar review to warn other divers away. A crew treating divers like that is not only rude, it also suggests they are incompetent and would be incapable of effectively responding to an emergency.

I've been quite tempted to leave a review, but I think I may be better starting off by writing the owner. This particular business has a good reputation and may just not have been a good fit for us. There were definitely good things about the company. We did encounter a couple of things that were questionable and we were not the only divers to give the side-eye to the situation. As a (now former) business owner, I would appreciate direct contact before someone posts a less-than-stellar review.

I will say some crews that seemed more experienced were very well organized, on time, and less rushed. All of the staff were friendly, but I really felt that the issues we did have were with the crews that were less experienced as a whole (based on conversations, not based on age). I felt like some of the issues could have been avoided had the crew been more of a mix of more experienced and less experienced individuals. The office people were mostly efficient and friendly - mostly - but then there were a lot of divers to deal with. I suppose the large number of people on the boats combined with all of the covid chaos likely did decrease the quality of the experience. Everyone is trying to bring in a dollar while still trying to follow the ever-changing rules.

I think the main thing we learned on that trip, besides working on our own skills, is that we're just not the type of people who like to dive in big groups or with cattle boat type dive operations. If we're going to have a guide, I don't want to be in a pile of 12 other divers. Plus, I hate feeling rushed and especially so in situations where missing small details can cause big trouble. We now look for smaller, more relaxed businesses to dive with. Found an awesome one in Mexico in February that we're going back to dive with in June.

 

[yle]

I've been quite tempted to leave a review, but I think I may be better starting off by writing the owner. This particular business has a good reputation and may just not have been a good fit for us. There were definitely good things about the company. We did encounter a couple of things that were questionable and we were not the only divers to give the side-eye to the situation. As a (now former) business owner, I would appreciate direct contact before someone posts a less-than-stellar review.

The clues you've dropped lead me to believe I have a good idea of the dive op you're referring to. If I'm right, I've dove with them quite a bit and never had a problem like the one you describe. In fact, we started diving with them years ago when they were a relatively small operation in south Florida.

If I'm right, then I agree with you: the owner and his QC staff would really like to hear about your experience. If you want to PM me the name of the op, I am curious to find out if I'm right.