WATER HARDNESS*

          Water hardness is  the amount of dissolved calcium salts, magnesium salts, iron and aluminum in water.  While salts occur in a variety of forms, typically found are calcium and magnesium bicarbonates (referred to as "temporary hardness") and sulphates and chlorides (referred to as "permanent hardness"). 

          Hard water prevents soap from lathering.  Most people cannot tolerate drinking water that exceeds 300 ppm carbonate, or 1,500 ppm chloride, or 2,000 ppm sulphate.  Livestock can usually tolerate much higher levels of hardness, but total dissolved solids >10,000ppm will create problems.

 Hardness Formula: 
           Total Hardness in ppm Carbonate = (ppm Calcium x 2.497)
            + (ppm Magnesium x 4.115) + (ppm Iron x 1.792)
            + (ppm Manganese x 1.822)

          Hard water is treated by either a zeolite process (home water softeners) or a lime-soda ash process (large operations).

          Other measurements of hardness are  "grains per gallon" and "degrees".  

Equivalents: ppm to grains or degrees:

          1 ppm = 0.058 grains/US gallon
          1 ppm = 0.07 Clark degrees
          1 ppm = 0.10 French degrees
          1 ppm = 0.056 German degrees
          1 French degree = 1 hydrotimetric degree
          1 Clark degree = 1 grain / Imperial gallon as calcium carbonate
          1 French degree = 1 part / 100,000 calcium carbonate
          1 German degree = 1 part / 100,000 calcium oxide
          1 grain/US gallon = 17.1 ppm
          1 grain/US gallon = 1.20 Clark degrees
          1 grain/US gallon = 1.71 French degrees
          1 grain/US gallon = 0.958 German degrees

*Disclaimer:  For information only.  Use official guides for more accurate information.