DOWEX Ion Exchange Resins WATER CONDITIONING MANUAL

Useful Graphs, Tables, and Other Information
Concentrations of ionic species in water have been expressed in different units in different countries.
Concentrations should normally be expressed in one of the following ways:
• As grams (g), milligrams (mg = 10 -3 Ã��Ã��Ã����������Ã� �Ã�Ã�� -6 g) of the (ionic) species per liter (L) or
cubic meter (m 3 ) of water.
• As equivalents (eq) or milliequivalents (meq = 10 -3 eq) of the ionic species per liter (L) or cubic meter
(m 3 ) of water.
Still widely used concentration units are:
• kilograins of CaCO3 per cubic foot (kgr/ft 3 )
• 1 French degree = 1 part CaCO3 per 100,000 parts of water
• 1 German degree = 1 part CaO per 100,000 parts of water
• grains CaCO3/gallon (U. S.)
• ppm CaCO3
• 1 English degree (Clark) = 1 grain CaCO3 per (British) Imperial gallon of water
Table 31 gives the conversion factors for commonly encountered units to milliequivalents/liter (meq/L)
and mg CaCO3/L. Multiply by the conversion factor to obtain mg CaCO3/L or meq/L. Divide by the
conversion factor to obtain the different units from numbers expressed as mg CaCO3/L or meq/L.
Table 31. List of conversion factors for common units to meq/L and mg CaCO3/L.
kgr/ft 3
Unit mg CaCO 3 /L meq/L
2288 45.8
1 grain/U.S. gallon 17.1 0.342
ppm CaCO3 1.0 0.020
1 English degree 14.3 0.285
1 French degree 10.0 0.200
1 German degree 17.9 0.357
DOWEX Ion Exchange Resins 74 Water Conditioning Manual