Calculating KH without a KH Test

[Reechard]

I didn't read all of this terribly closely, but there is one assumption that these all make along the lines of what others have said ignoring other buffers. This assumes that your pH and CO2 are directly related and mutually exclusive. The fact is that there are many other things that will affect your pH. From a ballpark point of view, this can be a reasonable approximation. From a quality control chemist point of view (me), I wouldn't lean to hard on it, as we say in the lab. But I admire your observation, in an ideal situation that would indeed be the case. Good luck finding ideality in this world though =)

 

[mr funktastic]

lepomis - how do 2 tanks measure so differently? u must be buffering the water somehow in one of the tanks. are u lowering your ph in one or raising the oh in the other? that will greatly affect the outcome of the equation.

 

[Lepomis]

Tank one uses tap water. Tank two I mix tap and distilled.