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Re: KH/co2 question

Cavan wrote:

<<Ok, about those co2/kh/ph charts. Why is there more co2 at a higher KH? 
If my KH is 2 and I add more carbonates but not more co2 (to KH 5), how 
could there be more co2? Does this make sense? >>

Let's say your pH is 7.0 and your KH is 4. From the chart you derive that 
your CO2 is 12 ppm. You are thinking that if you double your KH to 8, your 
CO2 will jump to 24 ppm. If only it were true -- we'd all be buying more 
baking soda instead of CO2 systems. What will happen is that your pH will 
go up to about 7.3, and your CO2 will remain at 12 ppm. The only way to up 
the CO2 is to put more CO2 into the water (or prevent more from escaping).

If you look in any given pH column, there *is* more CO2 at higher KH values 
-- but this is because for the pH to be the same when there is more KH, 
there has to be more CO2 in the water (acid balancing out the bicarbonate 
to keep the same pH).


Jared Weinberger