Gettiing to 32%

[wedivebc]

As moronic as this sounds, turn the tank over, then turn it right side up. Analyze. It might just read what you expected it to if it was recently blended.

Sounds ridiculous, and I used to clown on people who talked about this before I saw it myself.

Me too until I watched it work time and time again. I realized that the gas in a scuba tank is compressed to 200 times the density it is at 1 ATA and could therefore behave differently, more like a liquid when in a scuba tank. I know there are probably much more educated people than me shaking their head but I know what I see and nitrox mixtures do not instantly become homogeneous when first blended.

For the OP take your PADI table and plan a deco dive using EAD to the MOD of your target depth at 32% (you learned how to do that on your nitrox course right?) Now do the same dive using 28% and see if there is a difference. Now ask yourself do you really know the contents of your tank? What if you read 32% right after it was blended then you went to 130ft using what could potentially be 36%. Are you going to trust these variables to the dive shop tank monkey or take responsibility for you own safety?

---------- Post added December 1st, 2013 at 10:03 AM ----------

Wow you are so wrong...

Exactly which part is wrong?

 

[RJP]

I just take my double steel 108s and shake them like a martini shaker--don't you?

108's? Nah, I have my wife shake my 108's. The 119's are heavier...

 

[Superlyte27]

119's are heavier than 108's?

This spec sheet shows 42lbs vs. 46lbs. XS Scuba Worthington Steel Cylinder Specifications
108's weigh more than 119's.

 

[boulderjohn]

119's are heavier than 108's?

This spec sheet shows 42lbs vs. 46lbs. XS Scuba Worthington Steel Cylinder Specifications
108's weigh more than 119's.

He was just trying to trick his wife into doing the heavy lifting. Now he has to hope she doesn't read your post.

 

[PfcAJ]

Easy enough with my double AL80s. A set of steel HP119s are another issue altogether...

Weenie.

Do it with lp120s!!!

 

[RJP]

119's are heavier than 108's?

This spec sheet shows 42lbs vs. 46lbs. XS Scuba Worthington Steel Cylinder Specifications
108's weigh more than 119's.

I fill my 119's to 6,000psi...

:d

 

[altaskier]

I realized that the gas in a scuba tank is compressed to 200 times the density it is at 1 ATA and could therefore behave differently, more like a liquid when in a scuba tank.

The density is indeed very high, but it doesn't behave like a liquid. In a liquid, molecules "stick" to each other, though it's a dynamic phenomenon and they'll stick to one set of neighbors and then to different set; in a gas, they bounce off of each other without sticking.

 

[j2s]

If you request 32 you should get a mix between 31 & 33 at the most if the blender knows what they are doing and accounting for a slight variation in analyzers. But even at that it's usually less. Like maybe 1/2% or so. If they are telling you that 28 is going to magically become 32 by the time you get to dive sight they are full of crap. Stop wasting your money and just dive air. They don't know what they are doing, are ripping you off, have a bad analyzer, or are just full of it. I would not get mix from them of any kind.

Sent from my DROID X2 using Tapatalk 2

Ditto....I dive 32% regularly and analyze the tanks right after they're filled.......1/2% variation from 32% no problem, any more I'd be suspicious........a 1 to 2% variation will effect your MOD and Deco time......Especially on multiple dives.......

 

[Superlyte27]

Ditto....I dive 32% regularly and analyze the tanks right after they're filled.......1/2% variation from 32% no problem, any more I'd be suspicious........a 1 to 2% variation will effect your MOD and Deco time......Especially on multiple dives.......

If you're PP blending, you'll get a greater variation than 1/2% 99 out of 100 times, unless of course you're taking 12 hours to fill them. I'm guessing you're getting your fills from a bank.

 

[RJP]

If you're PP blending, you'll get a greater variation than 1/2% 99 out of 100 times, unless of course you're taking 12 hours to fill them. I'm guessing you're getting your fills from a bank.

I rarely get more than .5% variance from my target fill doing my own EANx PP fills. I do fill slowly, but not 12hrs slow. I do purge the valves for a second or two before analyzing, as I believe that the "last gas in" will collect in the valves/manifold. Maybe that helps?