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I went DIR... but my bungies pulled me back!
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Quick Question.

How is Heliair different from Trimix.

As I understand it Trimix is O2/N2/H2, by its name Heliair suggests H2+Air, that would be H2/O2/N2, which is the same as Trimix.

Have I missed something?
 

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The difference is how you blend it. With trimix you basically put in whatever helium you need, then any oxygen you need, then top up with air. This allows you to precisely set your oxygen fraction for your max depth, sort out you're end with helium and basically have the 'optimum' mix. However, it requires that bottles be oxygen clean (and whips etc) and that you have a supply of compressed air, helium and oxygen. Expensive. So an alternative is to add whatever helium you want then just top up with air - heliair. It means no need to buy oxygen or to oxygen clean kit. But it also means that the more helium you add the lower the oxygen fraction, which limits your depth range. So a less optimum but still very workable gas for less outlay. Also, the big advantage, you can top up  heliar fills time and time again - you just need to analyze for oxygen and you can then precicely calculate both the nitrogen and helium fractions as they are constant. With trimix you can't do this without a posh helium analyzer, meaning more wasted mix over a given years diving. Heliair tends to be used by home blenders and on expeditions where facilities are limited. Also you can buy some helium, put what you need in your bottles, then take em to the lds and get them filled with air. Analyze at home and voila - heliair without needing a trimix ticket. Very naughty indeed.
 

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[b said:
Quote[/b] (Darren27 @ June 05 2003,13:46)]that would be H2/O2/N2, which is the same as Trimix.
Erm, just a quick point, Helium is He, Hydrogen is H2.  Pumping H2 into your cylinders when you wanted He is liable to result in a big kaboom.
 

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<font color='#0000FF'>Purely for interest purposes only, the Comex divers have been experimenting with hydreliox , (Comex news)
which contains a hydrogen-rich mix, one guy (Théo
Mavratomos) used this in 1992 to go down to 701m , kinda puts John Bennets 305m a little into the shade eh?
Car-azy stuff
 

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<font color='#000F22'>why bother with either when a company is working on this  liquivent
and i thought they made it up for the film abyss
 

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I went DIR... but my bungies pulled me back!
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H2 ... He err.
Woops,  been along time since I did any chemistry.
Whats an extra electrons between friends (oh and the extra proton and neutron)
 
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