Ptarmigan wrote:
On Thu, 12 Jan 2006 10:57:14 -0600, Rocco Moretti wrote:

Not everyone has a KH between 1 & 8?

I did not say that they would have.

Sorry, I wasn't trying to be snippy. I was trying to answer your
question, and the question mark was an indication of unsureness:

they all require me to test the KH to know the mg CO2
What am I missing ?

Not everyone has a KH between 1 & 8?

That was just the range of values that I inspected.
quote (ie. all the KH's that I examined ) /quote
I was asking for clarification, not issuing a dictat.

And I was trying to to point out that the situation *might* change for
someone with a higher KH. I have a KH in the 15-25 range, and a GH to
match. It's sometimes hard to remember that not everyone has liquid rock
for water. I was thinking you too might have gotten into the trap of
thinking that everyone has water like yours. So although such a
technique works for low KH waters, it might fail for higher ones, and
"what you're missing" is that the internet websites have to give advice
valid for all water types.

The question mark was not intended to be sarcastic or anything, it was
merely indicating the fact that I don't know if the relation breaks down
in high KH waters, and didn't have time to check when I posted.

Looking at http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm,
it appears you are correct, and KH doesn't matter - at any given,
constant KH, the pH drop of a given increase in CO2 is independant of KH.