On 28/07/2011 10:38 PM, Le_Forgeron wrote:
> Le 28/07/2011 21:24, Orchid XP v8 nous fit lire :
>> http://www.ebuyer.com/179913-feser-aqua-ultra-pure-coolant-1l-fa-0054
>>
>> "...is extremely pure water..."
>>
>> "PH: 2.0 - 3.0"
>>
> more interesting: 1000ml ... 1,100g !

Um, yeah.

> (ok, maybe it's bottle+water)

Perhaps. But don't bet on it!

> And what is PH ? pH yes, but PH ?

Well, ebuyer is very bad at formatting product descriptions properly. 
Most of them look like they blindly copy/pasted from the manufacturer's 
website. Hell, whoever did this probably thought that "pH" was a typo 
and helpfully "corrected" it.

> Also, notice, once open, any floating dirt in the air will contaminate
> the water... in a fraction of second.
>
> In fact, the air inside the bottle is not clean enough... they should go
> the tires way: have it filled with 100% nitrogen (gas) instead of air.
>
> Oh, btw, what about dissolved gas into the water after a storage of a
> few weeks ? (closed bottled)

OK, well I work for a lab company, and we really do use chemically pure 
water, so this is a subject I know a little bit about.

Nitrogen dissolves in water. Not as readily as some gasses, but it does 
dissolve. Apparently helium is the thing to use. (Indeed, we have 
degassing equipment that works by merely bubbling helium through the 
liquid. Any dissolved gasses tend to precipitate into the helium bubbles 
and leave with them.) Helium is very, very insoluble in liquids. I don't 
know why.

For this application (i.e., liquid cooling a computer), dissolved gas is 
unlikely to be important. Also, while dissolved CO2 might make the water 
very slightly acidic, pH 2 is *very* acidic. Either they got their 
measurements hopelessly wrong, or this "very pure water" actually 
contains some kind of additive (perhaps to limit corrosion or something).

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