POLL, Nitrox tank use and analyze
- Thread starter ThomasScherrer
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A lot of people in this thread seem to have the idea that there are two choices for tanks. Either they are always used for nitrox, or they are never used for nitrox. That may be what many people think, but it is pretty old school thinking, and I don't know anyone who dives that way.
I don't own a whole lot of tanks, but the ones I own have had just about anything in them from dive to dive, depending upon what I am planning to do. My doubles have had everything from plain air to 15% O2 and 55% helium. My Al 80 has had anything from air to pure O2. My Al 40s have had anything from 50% O2 to pure O2. Everyone I dive with will tell you much the same thing.
Let's talk about the hogwash about never putting air in an O2 clean (nitrox) tank, because it can contain impurities that can create problems in the case of partial pressure blending. In partial pressure blending, pure O2 is introduced into the tank, and then the tank is topped off with air! Air is always introduced during partial pressure blending--it just has to be highly filtered air. Therefore, there is no problem in putting highly filtered air into an O2 clean tank, since it is going to happen regardless.
Since my tanks will change in contents from dive to dive, it would be silly to be putting big yellow and green stickers on and off them every time I dive. I therefore have one permanent sticker: a VIP sticker that says it is an O2 clean tank. When I fill it, I analyze it and put another sticker on, one describing the contents and identifying the MOD.
And yes, I will analyze it even if I think I am diving air--because I might be mistaken if the tank was topped off over some other mixture.
I don't own a whole lot of tanks, but the ones I own have had just about anything in them from dive to dive, depending upon what I am planning to do. My doubles have had everything from plain air to 15% O2 and 55% helium. My Al 80 has had anything from air to pure O2. My Al 40s have had anything from 50% O2 to pure O2. Everyone I dive with will tell you much the same thing.
Let's talk about the hogwash about never putting air in an O2 clean (nitrox) tank, because it can contain impurities that can create problems in the case of partial pressure blending. In partial pressure blending, pure O2 is introduced into the tank, and then the tank is topped off with air! Air is always introduced during partial pressure blending--it just has to be highly filtered air. Therefore, there is no problem in putting highly filtered air into an O2 clean tank, since it is going to happen regardless.
Since my tanks will change in contents from dive to dive, it would be silly to be putting big yellow and green stickers on and off them every time I dive. I therefore have one permanent sticker: a VIP sticker that says it is an O2 clean tank. When I fill it, I analyze it and put another sticker on, one describing the contents and identifying the MOD.
And yes, I will analyze it even if I think I am diving air--because I might be mistaken if the tank was topped off over some other mixture.
RonFrank
Contributor
The whole thing to me seems rather ridiculous.
Some fictitious diver is going to use someones tank (not theirs) without that diver knowing because they are napping and skipping a dive they planned. Further this irresponsible tank nabbing diver doesn't tell anyone, AND the tank is Nitrox AND unmarked AND this second dive is deep enough to cause issues. IOW deeper than 110' feet on EAN36 .
That's a lot of AND's, and IMO a lot of BS. You guys seem to dream up things I've never seen....
Some fictitious diver is going to use someones tank (not theirs) without that diver knowing because they are napping and skipping a dive they planned. Further this irresponsible tank nabbing diver doesn't tell anyone, AND the tank is Nitrox AND unmarked AND this second dive is deep enough to cause issues. IOW deeper than 110' feet on EAN36 .
That's a lot of AND's, and IMO a lot of BS. You guys seem to dream up things I've never seen....
Tigerman
Contributor
I HAVE seen people grabbing the wrong tanks and not even realizing till some of the boat crew was awake enough to ask them if they where nitrox certified, which they wherent..
You dont need to be a rocket scientist to get a certification to dive, so if you assume people can use their eyes, atleast dont assume they can use their brains..
You dont need to be a rocket scientist to get a certification to dive, so if you assume people can use their eyes, atleast dont assume they can use their brains..
pjhansman
Contributor
At the risk of derailing this thread.....could people give me an idea what their preferred analyser is for testing Nitrox?
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sorry.miketsp
Contributor
In this thread I earlier stated that I'd never seen EAN in unmarked tanks and I would consider it criminally irresponsible to do so. Well this weekend I went diving with an operator with whom I've dived many times over the last 10 years and I was surprised to see the attached. 39% in unmarked tanks except for a strip of crepe tape and I observed that the divers using the tanks were often coming back from the dives with the tape missing and over half a tank of pressure remaining. So even after the dilution from topping off the tanks with air, the next unsuspecting (air) diver will be getting a hot fill. When I complained about the lack of tank markings it was shrugged off with the answer that they rarely do any deep dives so it wasn't an issue. 
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unless the shop has 2 different testers is serves no purpose to use thiers. I use my own. I have my own and use it normally. I have dove nitrox in coz and when i checked a tank ,, the shops and mine there was 4 % difference. I used the higher value for table use. had mine checked when arrival to conus and found my unit was correct.so i paid for 36 and got 31+. I would bet they did not expect to be called on it and rhey saved money on the shop o2 bill. If it were legit then thier tester was off and my using it would have verified a wrong content was correct. What if i asked for 40 and got 46 insteaad for an 80 ft dive.
I may be incorrect in this but my understanding is that the nitrox tank wrap was not required for 40% and below It was to serve as notice not to fill with other than hyperfiltered air as either the sole gas of the mixing gas AND it is saying that no gas other than N2 O2 not to be put in this tank (NO TRIMIX OR ARGON). As most dont understand that it is not a wonder that some places will not fill a tank with 21% air if it has a wrap on it.
the purpose would be to be testing it in the first place
... my point above was that some people dont have a tester, but the shop or boat will (should) and to use it
... my point above was that some people dont have a tester, but the shop or boat will (should) and to use it
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