2 Tank Dive, Nitrox for Both?

[ChuckP]

I heard a few years ago they were PP blending. They probably can buy O2 for next to nothing with their gas supply connections.

They supply the hospitals here - I'm just surprised due to the logistics. There tanks are fairly consistent week to week and the only good thing that's come outa Covid, their tanks seem fuller!

 

[BRT]

They supply the hospitals here - I'm just surprised due to the logistics. There tanks are fairly consistent week to week and the only good thing that's come outa Covid, their tanks seem fuller!

They have more time to fill them now! A guy there told me once that they filled 2000 tanks a day. Don't know if it was true.

 

[ChuckP]

They have more time to fill them now! A guy there told me once that they filled 2000 tanks a day. Don't know if it was true.

I don't know if you've ever seen the building but when we first started opening back up, there were narrow aisle ways only in that back room, I've never seen so many tanks - the second week of March, that building was empty at noon - they fill a lot of tanks

Google Maps

 

[BRT]

I don't know if you've ever seen the building but when we first started opening back up, there were narrow aisle ways only in that back room, I've never seen so many tanks - the second week of March, that building was empty at noon - they fill a lot of tanks

Google Maps

Yes, I've seen their fill area. I rented tanks from them a few times. I can kind of imagine what it would look like if all the tanks were there and not somewhere else.

 

[yle]

So far I have not found a tank that wasn't within a couple percent of what it was labeled. I still test.

A few years back I went to test the "nitrox" tanks that were provided for my party. I had my own analyzer (the shop wasn't offering theirs.) The guy at the shop (who had the shop's analyzer...) insisted that I didn't need to test them, that he had already done so. I thanked him and told him I would test them anyway, since that was standard procedure. He seemed upset.

And he became more upset when I told him they tested at 21%.

He then used his analyzer, claimed mine must not work correctly, and tried to show me that I was wrong. After I explained to him how to use his analyzer correctly, he was able to verify that my "nitrox" tanks were actually filled with air.

Learned my lesson... now I always bring my analyzer to Coz and I always test my own tanks. I've never had a problem since, and the only guy that ever got upset with me testing my own tanks was the guy that tried to give me air instead.

 

[yle]

I got one tank that was off by 10%. I asked for 30% and got 40%. In the case of the place in question...2%+ off wasn’t uncommon (my dive buddy ran into similar discrepancies at the same place).

Any idea how they fill tanks where you got the 40%? I ask because a reading like this could be a miscalibrated analyzer. If, for example, a shop banks 36 and mixes with air to make 32, 30, whatever, then you know before you test that a 40% fill from such a system would be impossible.

Analyzers aren't perfect, and the accuracy of even the best analyzer is still at the mercy of the operator. Finding out how they fill might seem intrusive, but I would bet most shops would be happy to talk about it.

The shop I get most of my nitrox fills at locally uses a membrane system and they've explained that it can only go to a max of 36. If I got a 40% fill from them, I'd find a second analyzer.

Anyone know how nitrox fills, in general, are done on Coz? Considering the volume, I would assume banking would be a necessity.

EDIT: I posted the above before I caught up on the discussion from the last page of posts... with Chuck and BRT talking about this very thing. Thanks!

 

[yle]

Sound advice, everyone probably should have their own analyzer. But not offering analyzers to customers is pretty far from OK in my book.

Or if they're not going to offer the analyzer, they should offer to analyze with the diver watching. It's unrealistic (and irresponsible) to expect every nitrox user to have an analyzer. I only bought one because I started teaching the nitrox class and I got a great deal on the analyzer.

Our go-to shop in Key Largo used to pass their analyzer around the boat for customers to use. But apparently they were replacing the $120 O2 sensor a little too frequently... so a while ago they switched their policy so that one of the shop DMs would analyze each nitrox tank while the diver observed.

 

[yle]

It was partial pressure blended. In the U.S. though...not Mexico.

Thanks... I saw this post after I posted above, asking about the fill method.

 

[living4experiences]

After reading these five pages, here's my two cent. For multiple dives over consecutive days, I use Nitrox to aid in the slowing of the nitrogen load on my body. I know that's not the scientific way to put it, so the techies here don't need to correct me. $8 per tank is not a bad investment in your health and safety. Feel lucky it's only $8. I'm going to south Florida in October and the nitrox is outrageously and stupidly priced at $15-$16 per tank. I'll pay it begrudgingly because there's no choice.

As far as the analyzer, it is unacceptable that any shop in the world would not have an analyzer in the shop or on the boat. In one sense, it's your responsibility to make sure you get what you pay for and dive accordingly, and in another sense, it's their responsibility to prove to you you're getting what you paid for. In no way should it ever be up to the diver to bring their own analyzer.

I was nitrox certified a couple of years ago at Blue Magic Scuba in Cozumel and went on to dive with them for the week, each time analyzing the tanks with their analyzer. Last December, I returned to Cozumel and stayed at El Cid La Ceiba and used their on-site dive shop, Babeica. To my shock and surprise, they don't analyze nitrox tanks and do not even have the tool in their shop. On the first day of diving, I asked for it and the shop owner said, "Oh, the whole island gets their tanks from the hospital and we don't have to analyze." So they don't even know what their mix is because they never check it themselves. I was more than bothered by that. So I have no idea what I was diving on all week...air? nitrox? weak nitrox? This issue coupled with the fact that the reef was in terrible shape last December, I'm not going back to Cozumel for awhile. And now I will not dive with a shop who doesn't analyze their tanks and will definitely inquire before I dive with any operator in the future.

 

[scubadada]

Hi @living4experiences

In SE FL, renting a nitrox tank generally costs about $5 more than an air tank. All the operators I use have analyzers, I also have my own