Beginner question about Nitrox analyzers

[Crazy_Canuck]

really didn't think i would need one until i got gas fills at the dive site after having 36% in my tanks and then i had to calculate 700psi of 36 to top up at 3000 with 21 what do i have? to be safe you have to dive it at 36% for PPO2 and dive it at 21 for nitrogen loading. is you life worth a couple hundred to ensure you know what you are diving?

 

[jblack]

I will be doing my Nitrox course soon and have read that some people buy their own analyzers. Is this necessary or will the dive op/liveaboard that provided you with the Nitrox tanks also have an analyzer you can borrow? I'm just wondering if it's an immediate need if I'm gonna be using Nitrox or just a "nice to have" so I don't have to be sharing with others on the boat? Thanks!

BUY YOU'RE OWN. most of the ones at the dive shops are beat, not maintained, etc....

 

[Crazy_Canuck]

HOLLY ****. just yell at us. i bought my own....... that was the point of my post.....i just spent 2500 on a new drysuit, working on 1200 for new BCD. countless trips to Bonair,Tobermory, 2 hr drives to go diving every weekend. of corse i will spend a couple hundred to buy an analyser...... Take it easy buddy

 

[Crazy_Canuck]

jblack did you give up that easy? LOL

 

[Ghetto Diver]

really didn't think i would need one until i got gas fills at the dive site after having 36% in my tanks and then i had to calculate 700psi of 36 to top up at 3000 with 21 what do i have? to be safe you have to dive it at 36% for PPO2 and dive it at 21 for nitrogen loading. is you life worth a couple hundred to ensure you know what you are diving?

Can read your post two ways, but you would end up with either either 24 or 32. Plenty of apps to figure this out. Of course, confirming with an analyser is warranted.
As far as shop units being beatup etc.... I can check calibration myself with o2 at my shop. Even when I had my own unit, there was a semi consistent 1% difference in readings.

 

[tursiops]

Can read your post two ways, but you would end up with either either 24 or 32. Plenty of apps to figure this out. Of course, confirming with an analyser is warranted.
As far as shop units being beatup etc.... I can check calibration myself with o2 at my shop. Even when I had my own unit, there was a semi consistent 1% difference in readings.

Checking the calibration against O2 is not the best plan. Using (room) air is better, because 21% is close to 32/36% than is 100%. The sensors are not linear, so you can easily get that 1% difference by calibrating against O2.

 

[tursiops]

There is a bit of confusion in this thread between the necessity to analyze each tank, and the convenience of doing it with your own analyzer.

 

[Ghetto Diver]

Checking the calibration against O2 is not the best plan. Using (room) air is better, because 21% is close to 32/36% than is 100%. The sensors are not linear, so you can easily get that 1% difference by calibrating against O2.

True. I rarely calibrate theirs though.
My point is there may be a difference in readings. I have seen customers get flustered with a difference of 1% of requested blend (rec diving).
I had the same analyser, Miniox, as the shop, diffferent sensor.

 

[Hatul]

Never trust the blue tape. Analyze yourself. Too many factors: was it calibrated, did the person actually analyze, is the number the current %.

Buy an analyzer for CO and nitrox and use both every time.

As Ronald Regan stated: Trust but verify.

 

[yle]

Can read your post two ways, but you would end up with either either 24 or 32. Plenty of apps to figure this out.

Or just use some basic math. With a little practice, it's actually quicker than pushing buttons on an app.

700 @ 36% and 2300 @ 21%

(700 x 36 + 2300 x 21) / 3000

(7 x 36 + 23 x 21 ) / 30

(7 x 12 + 23 x 7) / 10

( 84 + 161) / 10

245 / 10

24.5

So the mix would be 24.5% O2.