Originally Posted by Nemo the Clownfish
Byron, sorrry if I'm not being clear. I don't want to do anything with the information. I just wanted to know what those carbonates and bicarbonates are doing and how the buffer works chemically. I understand that this is part of the Carbon Cycle, or at least I would think so. I'm interested in these things. Sorry if i'm asking a weird thing or not speaking in a way that is clear to you.
As a chem student you may well know more about this than I do.
But I'll try to explain what I understand from my aquarist's perspective.
The carbonate and bicarbonate ions in the water do the buffering. These are related to minerals, primarily calcium and magnesium but a few others can also be present. As carbonic acid is produced through the biological processes in the aquarium they are taken up by the carbonates, thus maintaining a steady and stable pH. The more carbonates (= higher KH) the more they can do this. Without carbonates, as in very soft water, the production of carbonic acid will lower the pH because there are no carbonates/bicarbonates to take it up.
Live plants are a factor in this process due to their impact on the amount of dissolved carbon, CO2, in the water.