Dissolving CO2 in water increases bicarbonate concentration, so why
would it not increase KH?

Okay, I think I understand what you're asking. Sorry, I think we hit one of
those "two nations separated by a common language" potholes in the earlier
post. g When you said "bicarbonate," I thought you meant baking soda, since
bicarbonate means baking soda in many parts of the U.S.

CO2 added to water mostly stays CO2. A fraction of a percent of it becomes
carbonic acid, and that's what causes the pH drop. It doesn't affect KH, as we
measure it, anyway.

For chemistry meeps:

http://www.thekrib.com/Plants/CO2/alkalinity.html

http://www.thekrib.com/Plants/CO2/kh-ph-co2.html



Leigh

http://www.fortunecity.com/lavender/halloween/881/