I just found this on the Krib...
"Also, most KH test kits actually measure total alkalinity. If KH is the predominate component of alkalinity, all is well. However, if other buffers are in the water (phosphate buffering products, for example), you will get a higher "KH" reading and you will think you have more CO2 than you really have."
If this is the only issue with the accuracy of the table...it's not an issue for me, because since my tap water KH is 0, I know that all KH in my water is only from what I've added, namely, the baking soda.
"Also, most KH test kits actually measure total alkalinity. If KH is the predominate component of alkalinity, all is well. However, if other buffers are in the water (phosphate buffering products, for example), you will get a higher "KH" reading and you will think you have more CO2 than you really have."
If this is the only issue with the accuracy of the table...it's not an issue for me, because since my tap water KH is 0, I know that all KH in my water is only from what I've added, namely, the baking soda.