Alkalinity, in place of carbonate hardness, or dKH.
Alkalinity refers to the pH of any substance north of 7.0. Carbonate hardness refers to the amount of carbonate disolved in solution. The two terms are not interchangeable, yet they are within our hobby with great regularity.
This one has bugged me for years (decades, actually).
I did not know this. Learning new things
. I will now refrain from using the term Alkalinity 

. I still don't even know how sicce is pronounced


