Tank = Confusion AGAIN!!!!!!!

[CompuDude]

CJ, I don't disagree with you at all... we both know what we're talking about. But there are definitely some translation errors with what the shop actually said, at least, as reported, because what (we assume) they meant is NOT what was said: Air + PP Nitrox is ok. Obviously, it's not.

 

[rleslie]

When I arrived at the shop, they had several HP80 tanks sitting out. I purchased one and they proceeded to: a)put a light stick into the tank and quickly looked inside b) put a compound onto the threads and screwed on the valve. c) asked me if I would be using it for Nitrox. I stated that I would like to use Nitrox but it would always be less that 40% and I would be using only premix. d)They stated that I should not use premix, but should use partial pressure blend and what ever shop was filling the tank should put in pure O2 first when doing a PP.

That is when I questioned them. I specifically said that it was my understanding that if I wanted to use both regular air and Nitrox in the same tank and not have to have it cleaned, I should use premixxed and always stay under 40%. They repeated what they had originally stated: that PP blend should be used NOT a premix.

 

[Isaac-1]

Not meaning to hijack this thread, but does all this mean we need a new Nitrox tank label, one that denotes use of EAN40 premix or less for non O2 clean tanks?

 

[ClayJar]

Not meaning to hijack this thread, but does all this mean we need a new Nitrox tank label, one that denotes use of EAN40 premix or less for non O2 clean tanks?

No. A nitrox sticker does not serve to indicate a cylinder is O₂ clean.

(On my nitrox cylinders, my visual inspection stickers indicate whether the cylinder was cleaned for high oxygen use.)

 

[CompuDude]

When I arrived at the shop, they had several HP80 tanks sitting out. I purchased one and they proceeded to: a)put a light stick into the tank and quickly looked inside b) put a compound onto the threads and screwed on the valve. c) asked me if I would be using it for Nitrox. I stated that I would like to use Nitrox but it would always be less that 40% and I would be using only premix. d)They stated that I should not use premix, but should use partial pressure blend and what ever shop was filling the tank should put in pure O2 first when doing a PP.

That is when I questioned them. I specifically said that it was my understanding that if I wanted to use both regular air and Nitrox in the same tank and not have to have it cleaned, I should use premixxed and always stay under 40%. They repeated what they had originally stated: that PP blend should be used NOT a premix.

I wasn't there. But I call BS. Someone is clearly misunderstanding something somewhere along the road here.

You can freely switch back and forth between (1) pre-mixed Nitrox (from banks, stik systems, membrane, etc.) that is or is not o2 clean, to (2) plain, regular scuba air from any normally maintained scuba air compressor, with no need to maintain a tank in an o2 clean state. Period, end of story.

Nitrox does not equal <> PP blending... there are lots of ways to get it without exposing a tank to pure o2 at any point.

And as long as your tank will NEVER be exposed to pure 100% o2 (or any o2 percentage higher than 40%, for that matter), there is NO need to keep it o2 clean.

IF, however, you will ever fill your tank via PP blending, a process that normally exposes your tank to higher percentages of oxygen, you MUST keep the tank in an o2 clean state, and can never put in "plain" air (air that has not been hyper-filtered to an oxygen-compatible state). Well... you can, but the moment you do, your tank is no longer o2 clean and will have to be re-scrubbed and serviced before you can use it for PP Nitrox again.

 

[rleslie]

I wasn't there. But I call BS. Someone is clearly misunderstanding something somewhere along the road here.

You can freely switch back and forth between (1) pre-mixed Nitrox (from banks, stik systems, membrane, etc.) that is or is not o2 clean, to (2) plain, regular scuba air from any normally maintained scuba air compressor, with no need to maintain a tank in an o2 clean state. Period, end of story.

Nitrox does not equal <> PP blending... there are lots of ways to get it without exposing a tank to pure o2 at any point.

And as long as your tank will NEVER be exposed to pure 100% o2 (or any o2 percentage higher than 40%, for that matter), there is NO need to keep it o2 clean.

IF, however, you will ever fill your tank via PP blending, a process that normally exposes your tank to higher percentages of oxygen, you MUST keep the tank in an o2 clean state, and can never put in "plain" air (air that has not been hyper-filtered to an oxygen-compatible state). Well... you can, but the moment you do, your tank is no longer o2 clean and will have to be re-scrubbed and serviced before you can use it for PP Nitrox again.

No misunderstanding:no. I was very specific in my questioning. The sales person had already put "plain" air into the tank when they said that who ever fills it by PP blend will put pure O2 in first. THAT is what threw me and I questioned it, based on the explanations from the other thread. My understanding of this subject was exactly as you described in your post above, but they restated that PP was the proper method to use on future fills, not once, but twice. That's why I started this thread, to ensure that I had a proper understanding.

Perhaps their "plain" air is clean??

Thanks for your additional comments!!!

Roger

 

[CompuDude]

No misunderstanding:no. I was very specific in my questioning. The sales person had already put "plain" air into the tank when they said that who ever fills it by PP blend will put pure O2 in first. THAT is what threw me and I questioned it, based on the explanations from the other thread. My understanding of this subject was exactly as you described in your post above, but they restated that PP was the proper method to use on future fills, not once, but twice. That's why I started this thread, to ensure that I had a proper understanding.

Perhaps their "plain" air is clean??

Thanks for your additional comments!!!

Roger

I agree, I think you've got it right... I have to wonder about that shop dude, though.

If their "plain" air is o2 compatible, then their comments make more sense, but are still incredibly poorly phrased, because it makes it sound like they're telling you that you can put "plain" air in your tank and still use PP for Nitrox. That's true... if you only EVER get fills at their shop (and this still assumes they have o2 clean air, which has yet to be confirmed!). Their advice falls apart the first time you hop on a boat which puts actual "plain" (non o2 clean) air into the tank.