General hardness and total hardness are the same. This refers to the
content of certain metallic ions present in the water, mainly calcium and
magnesium (which form carbonates, bicarbonates, hydroxides etc.).

General Hardness is a subset of the total dissolved ionic salt content of
the water.

Carbonate hardness (KH) is a subset of general hardness and is a measure
primarily of bicarbonate ions present, and as such is very closely linked to
alkalinity.

In other words, there is the total dissolved salt content of the water--of
which general hardness refers to the measure of certain types of these
dissolved salts and carbonate hardess (KH) refers to primarily one of the
dissolved salts that make up general hardness.

BTW I believe carbonate hardness is abbreviated KH because it is an
abbreviation of the phrase in german.


"TEACHSKIP" wrote in message
...
Can someone answer this please. What is the difference between General
hardness
and total hardness and how does it relate to KH?

TIA