The GH and/or KH tests are titrations in their purest sense - add drops one at a time, mixing each time, keeping track of the drops until you get a color change from whatever the color was starting out to the color of the solution bottle (I think it starts out orange when you add drops, then changes to green or something like that).

The # drops = degrees of KH. Degrees*17.9 = ppm.

__________________
Officially fishless until after the move....tune in later for details!