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View Full Version : Do You Analyze All Tanks?



Iceman
10-13-2007, 11:47
Other threads have asked if you use your own or the shop's nitrox analyzer to check your tanks. But, if it is a shop or boat that provides both nitrox and air, how do you know which you have? Do you rely on the label, or lack thereof? Or, do you analyze all tanks?

Do you have nitrox at some percentage? Or, do you have air? Did the underpaid and overworked person who filled the tanks accidentally get nitrox at 36% (a standard mix) into that air tank? Or, if they also service technical diving, do you have 80%EAN in that tank that has no label on it?

CompuDude
10-13-2007, 14:16
Most of my fills are done at a shop that only pumps air. I don't analyze those tanks unless they were topping off a tank that had Nitrox in it, in which case I might end up with 28% or so, so it's worth checking.

On boats that offer Nitrox, I generally use it, and of course will always analyze. And when taking my tanks to other shops, I check it when I'm getting Nitrox (of course), but I generally watch my tanks getting filled so I can see what whip gets connected.

So... yes and no. Not sure how to answer poll given the answers available. :) But it seems common sense goes a long way... if you frequently get fills at a shop where confusion is possible or even has a higher potential, you should check. If not, there's not as much need.

Dive-aholic
10-13-2007, 15:29
Same as Compudude. If the shop fills anything other than air, then the tanks get analyzed. There's no way to know what banks they're filling from unless you watch which bank they're taking it from. Even then, I want to make sure they didn't mess up the banks and accidently put oxygen in the air bank. I even analyze my 100% fills. I see it coming out of the oxygen bottle, but how do I know the oxygen supplier didn't screw up?

No Misses
10-13-2007, 15:35
I check all tanks. I once ended up with 21 when it should have been EAN36. This could have ruined my 3 tank dive day :-(

in_cavediver
10-13-2007, 15:48
For me, when in doubt, I analyze. As I stated on a prior thread, I got my own analyzer to combat complacency. Its just to easy now to analyze my gas.

That said, if the dive is in one of the local quarry's with a hard bottom of 30ft, I don't worry to much about my gas or knowing if I have 32, 21 or something in between. (unless I have hypoxic something or trimix sitting around, then I analyze EVERYTHING I use until its gone). The quarry pumps only air and I really don't care what I am breathing so long as its not hypoxic. (I have dedicated 45's as 02 bottles and permanently labeled 50/50 bottles).

danielh03
10-13-2007, 16:49
The place I get my fills at I would never have to worry, the guy is to anal to mess up like that. But if I am at the quarry, I tend to wonder. Maybe time to purchase an analizer

Dive-aholic
10-14-2007, 20:45
The place I get my fills at I would never have to worry, the guy is to anal to mess up like that. But if I am at the quarry, I tend to wonder. Maybe time to purchase an analizer

A woman almost died a couple of years ago because her fiance messed up the mix. She trusted him. Do you think it's really smart to trust some stranger in a shop? Everyone has bad days...

tremtech
10-14-2007, 21:11
I always watch the fill at my lds, the whip for nitrox is green color coded and they have to use a din adapter.The air whip is plain old nickle .If I'm diving 50' or less I use air for the dive, but if I'm diving a mix I analyze with their analyzer. My lds is one of the best shops as far as experienced operators go, they also drain a tank that is being used for nitrox before filling it it makes the mix more accurate.

CompuDude
10-15-2007, 02:10
I always watch the fill at my lds, the whip for nitrox is green color coded and they have to use a din adapter.The air whip is plain old nickle .If I'm diving 50' or less I use air for the dive, but if I'm diving a mix I analyze with their analyzer. My lds is one of the best shops as far as experienced operators go, they also drain a tank that is being used for nitrox before filling it it makes the mix more accurate.

It doesn't make it more accurate. It makes it easier to do without having to think.

Iceman
10-15-2007, 10:07
Interesting responses.

Of course, if the place you are obtaining your breathing gas only has air you can be pretty well assured what is in the cylinders filled there is air.

But, if it provides both air and nitrox there are only two ways to be assured what is in the cylinder is what you want. Neither way is to rely on cylinder labeling.

The first way is to be sure the filling connection is labeled as air. That is pretty reliable if you can see plumbing routing.

The second way is to analyze all tanks. Of course this is the best way to be assured what you want is what you get.

cummings66
10-15-2007, 10:10
On some tanks like mine which are HP tanks it's easier to fill it. I often finish a dive with 1000 or more psi in the tank and without boosting the O2 you'd find it hard to get a mix without draining the tank.

You can do it by numbers, but since the O2 supply tank is LP and most likely has done a few fills it's probably way short of 2000 psi, so it's tougher to get a mix.

Dive-aholic
10-15-2007, 19:23
Interesting responses.

Of course, if the place you are obtaining your breathing gas only has air you can be pretty well assured what is in the cylinders filled there is air.

But, if it provides both air and nitrox there are only two ways to be assured what is in the cylinder is what you want. Neither way is to rely on cylinder labeling.

The first way is to be sure the filling connection is labeled as air. That is pretty reliable if you can see plumbing routing.

The second way is to analyze all tanks. Of course this is the best way to be assured what you want is what you get.

Some shops use the same whip for both air and nitrox. They just switch over close one valve and open another. It's not always easy to tell where the plumbing is leading to.

Iceman
10-16-2007, 16:48
Interesting responses.

Of course, if the place you are obtaining your breathing gas only has air you can be pretty well assured what is in the cylinders filled there is air.

But, if it provides both air and nitrox there are only two ways to be assured what is in the cylinder is what you want. Neither way is to rely on cylinder labeling.

The first way is to be sure the filling connection is labeled as air. That is pretty reliable if you can see plumbing routing.

The second way is to analyze all tanks. Of course this is the best way to be assured what you want is what you get.

Some shops use the same whip for both air and nitrox. They just switch over close one valve and open another. It's not always easy to tell where the plumbing is leading to.

Right on, unless you can verify for certain where the breathing gas came from it is always best to analyze, no matter what the cylinder label says.

tremtech
10-19-2007, 09:03
Well , that is the point of the analyzer if their air bank is contaminated with o2 how would you know since you have to calibrate the analyser to a tank with just plain old air which most likely just came from their air whip. If you get a reading of like 25% o2 from the regular air tank you might want to find a new shop IMHO

No Misses
10-19-2007, 09:21
I keep hearing people say that they calibrate thier O2 sensor by using an "air" tank. As tremtech stated " how do you know it has air in it"? I calibrate the sensor by sucking ambient air through the sensor (yes, i said suck, keep your childish comments in check). Some sensors are more open and can be calibrated by waving your hand in front of the sensor/ moving air past the sensor. By doing it this way, I am assured that I am using ambient air to calibrate the sensor. JM2c

Dive-aholic
10-19-2007, 16:11
Some analyzers don't work that way. You need to connect an air source to it to get air into it. Ambient air will also have an effect on the calibration. When I lived in Arizona and came to Florida every few months I saw a 2% difference in readings based on ambient air. The humidity makes a difference in the calibration.

How do you insure you have air? Get a tank filled at a shop that doesn't fill nitrox and calibrate off that tank.

Iceman
10-19-2007, 17:40
Posts 15 and 16 are testimonials to the fact that there is no substitute for knowing your kit and how to use it.

CompuDude
10-19-2007, 18:06
Posts 15 and 16 are testimonials to the fact that there is no substitute for knowing your kit and how to use it.

RTFM applies in most instances. LOL