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Re: Aquatic Plants Digest V4 #1480

> Simple experiment:  Put your distilled water,
>> and your tapwater under aeration and measure the
>> pH.  The deionized water in my lab usually rings
>> in at a pH of 4.5 wheras the tapwater is about 7.1.
> Ah, but wouldn't this come a lot closer to explaining the difference in
> bicarbonate concentations than absorption? And if both had the same
> concentrations, whether zero or a particular amount, wouldn't their pH
> values be the same within the same room? (BTW, your tap sounds like it's at
> about the same as mine here in Tennessee - see
> http://www.tawc.com/ourwaterqual/data.html for most of the pertinent
> measures.)

I'm just saying that purified water always seems to have a lower pH than 
you would think.  Think about it, Deionized comes out at about 4.5, it 
fluctuates alot but thats about what it is.  Now pure gas free water has 
a pH of 7.0 by definition.  So there is about a 2 or so pH drop from 
CO2.  I think its because CO2 is more soluble in pure water, But I'm 
just guessing.  If this is the case it does have bearing on the 
situation in the sense that people with liquid rock would see less 
equilibrium CO2 than people like us who have to add minerals.