Enter the water hardness value, in parts per million, into the calculator. Double-check the entry to ensure that it is accurate. Divide the ppm hardness value by 17.1, the conversion factor for ppm to gpg. The result is the water hardness expressed in grains per gallon. For example, say...
Convert Parts Per Million to Nanograms Per Microliter (ppm in ng/μL). Parts Per Million and Nanograms Per Microliter both are the units of DENSITY. See the charts and tables conversion here!