General Hardness GH vs. Carbonate hardness KH

["William M. Groth" <groth@rice.edu>]

I am sure this has been covered many times but here goes.

I have a water softening unit which uses DI resins which are regenerated
with Potassium salts.  We also have a carbon unit for the residential system
which removes chlorine, chloramines, etc.  

We have tested our water and the GH was approx.  .5 dH (less than 10 ppm)
but the KH was approx. 9.5 dH ( or 170 ppm).  Does anyone out there know just
exactly what the Tetra test kits for GH/KH actually measure and why the 
carbonate hardness KH would be so much greater than the general hardness GH??
______________________________________________________________________

       William M. Groth
       groth@ruf.rice.edu
       Senior Staff Auditor
       Internal Audit Department
       phone: (713) 527-8101 ext.3759
	fax:  (713) 285-5927
_____________________________________________________________________