Why is Nitrox so expensive (and so hard to get)?

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On the other hand I just filled 15 tanks mixing in a stick and ran my O2 tank to empty without a booster or very much danger of an O2 mishap. Mixing nitrox is not rocket surgery and does not cost that much. Three of us dive a few dive trips a year and I mix nitrox. It adds about $2.00/tank for the O2.

Yes, it's a cheaper way to mix nitrox than a membrane system and is used by many shops around the world. Word of advice, analyze each tank for CO with the risk of adiabatic heating and compressing o2 enriched air. There was recently a very well known fill station blending nitrox whose system was compromised from a flash fire in the filter. CO analyzers are cheap, they're portable, and could save your life or someone you care about lives. Hopefully not too O.T., but it should be an additional practice everyone takes when doing gas analysis before EVERY dive when switching to a new tank or topping off an existing.

Forgive the cross linking, but here's a link of the incident in mentioned above. I know quite a few people who were effected by this incident and others:

CO Incident
 
For those quoting prices of Nx tank fills, can you also include the buy cost for your O2 so it can be seen in perspective.

An 11 litre cylinder (80) requires about 300 litres of O2 to make 32% (regardless of metric or imperial, or the method of how you get the oxygen into the scuba cylinder) thus at $2 per tank that's 0.005 cents/litre for the O2, or about $50 for a G cylinder of oxygen. Is this correct? also are you using industrial gas, medical gas, aircraft gas (or perhaps voodoo gas).
 
While I understand your cost analysis, remember that they're already charging you $20/tank for air. And then demanding an extra $25 on top of that for nitrox. So you're paying $45 for a single tank of nitrox, not $25. I lived in Perth for a number of years and could get a tank of nitrox for $16. So I don't know what these guys here are doing that triples their costs. Although given that I could get my regs serviced in Perth for $110 and here it's $240, I suspect it's just pure price gouging.

A bit off topic, but for great quality reg servicing at a decent price try Diverepairs on the goldcoast. You can even mail them your regs.


Sent from my iPad using Tapatalk
 
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A bit off topic, but for great quality reg servicing at a decent price try Diverepairs on the goldcoast. You can even mail them your regs.


Sent from my iPad using Tapatalk

I now do my own, cheaper and I know the standard that they are done to. This is after a number of bad services.
 
A bit off topic, but for great quality reg servicing at a decent price try Diverepairs on the goldcoast. You can even mail them your regs.


Sent from my iPad using Tapatalk

Yeah, I didn't know any better at the time. I'd only just moved to Townsville and just figured it'd be around the same price as Perth. Because Perth is just expensive in general. I was gobsmacked when they told me how much it was going to cost. Was told I could pick them up in a week - didn't get them back for 6.5 weeks. You can tell how much I love the LDS here, right?

Still, thanks for the tip. It sounds like it may be cheaper to send them down south, or maybe even up to Cairns for servicing this year. I'd do it myself, but they're still under warranty, and don't want to mess with that.
 
As someone who has been a gas monkey, for a few different dive operations in Aust, general obsevations have been:

If you have lots of divers wanting Nitrox, buy a membrane compessor.

If the demand is not high enough ,then blend your own nitrox.

Buying a membrane compressor costs lots, but once it warms up, will fill lots of tanks at about same speed as an equivalent air compressor.

Blending nitrox, if all your equipment( compessor, fill whips, tanks/valves etc) is O2 cleaned, has a lower capital cost. But it takes lot longer per fill, so labour cost per fill is a lot higher.


However an Additional $24 per fill sounds like a lot extra, no matter which method the used.
 
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As someone who has been a gas monkey, for a few different dive operations in Aust, general obsevations have been:

If you have lots of divers wanting Nitrox, buy a membrane compessor.

If the demand is not high enough ,then blend your own nitrox.

Buying a membrane compressor costs lots, but once it warms up, will fill lots of tanks at about same speed as an equivalent air compressor.

Blending nitrox, if all your equipment( compessor, fill whips, tanks/valves etc) is O2 cleaned, has a lower capital cost. But it takes lot longer per fill, so labour cost per fill is a lot higher.


However an Additional $24 per fill sounds like a lot extra, no matter which method the used.

To what purity can you deliver oxygen from a membrane? 100%
 
You'll typically get around 95% or so. The exact output seems to depend on what you had for breakfast that day :wink:
 
I can probably get slightly cheaper rental from another gas company which I will try this in future. I could also use industrial grade oxygen which is cheaper, however given I am playing with my life, I like using medical grade. I believe the actual physical difference is that medical grade, on every occasion the cylinder is evacuated before filling, filled and then tested. Industrial grade its just refilled and not evacuated before filling or tested (except on a random cylinder basis perhaps). I believe the oxygen source is the same for both grades of oxygen. The real difference being that the medical grade is guaranteed to be 100% oxygen and no mixed gases and is certified as such. The industrial grade (while probably 100% oxygen) could potentially have other gases thus the actual gas content is not known or certified but only assumed to be 100% oxygen.

Over here in the land of litigation, Industrial, Medical and Aviation O2 all come from the same tank. I've been told by knowledgeable counter-men that Industrial O2 is actually cleaner (less impurities) than Aviation or Medical because you and I can breath crap (e.g. live in a big city), but contaminated O2 really mucks up a weld.

Given the paranoia about filling a potentially contaminated tank with pure O2 under pressure, I'm not sure where the requirement to purge tanks before filling comes from. Here is a very brief summary from Airgas:

Oxygen
Purity99.5%
InertsLess than 0.5%
Dew PointLiquid Oxygen: -80ºF or lower
Medical Oxygen – meets Oxygen USP
Oxygen99.0%
OdorNone
 
Yes, it's a cheaper way to mix nitrox than a membrane system and is used by many shops around the world. Word of advice, analyze each tank for CO with the risk of adiabatic heating and compressing o2 enriched air. There was recently a very well known fill station blending nitrox whose system was compromised from a flash fire in the filter. CO analyzers are cheap, they're portable, and could save your life or someone you care about lives. Hopefully not too O.T., but it should be an additional practice everyone takes when doing gas analysis before EVERY dive when switching to a new tank or topping off an existing.

Forgive the cross linking, but here's a link of the incident in mentioned above. I know quite a few people who were effected by this incident and others:

CO Incident

I monitor the CO all the time. So far have never seen it over 0.0 except when testing.

I don't believe tanked O2 is cheaper than a membrane system after you have bought the membrane system. Two shops I bought from in Mexico charged an extra $1.50 for 32% over air. That is less than my cost of welding oxygen in 32%.
 
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https://www.shearwater.com/products/swift/

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