funny. No? Ok… I will continue. The two measures are KH and GH. KH stands for Carbonate Hardness (or
Karbonate, If that will help you remember it) and GH stands for General Hardness.
I am going to rely a little on Wikipedia here for certain numbers and reactions, so bear with me.
Carbonate Hardness is a measure of the dissolved carbonate (CO3 2-) and (HCO3 - ) bicarbonate Ions in the
water. It is measured in ppm which is equivalent to mg/L which isn’t at all equivalent to one dKH, the
conversion factor according to Wikipedia is one dKH is equivalent to ‘17.848 milligrams of calcium carbonate
(CaCO3) per litre of water (17.848 ppm)’. Carbonate hardness due to being composed of Magnesium (Mg)
and Calcium (Ca) and other multivalent (more than +1 charge) metals is expressed as if all the carbonates
came solely from calcium. Similarly, bicarbonates are expressed as if they were equivalent concentration of
carbonates.
General Hardness is simply a measure of the concentration of multivalent metals in a litre of water, it is again
expressed in a number equivalent to all the metal concentrations coming solely from CaCO3. It is expressed in
ppm of Ca 2+ or dGH.
OK, so the verdict on hardness is that hardness acts as a buffer to prevent pH changes. Hardness however,
does also have the effect of increasing pH, the harder your water, the higher your pH. It also means that it is
incredibly difficult to