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The grain per gallon (gpg) is a unit of water hardness defined as 1 grain (64.8 milligrams) of calcium carbonate dissolved in 1 US gallon of water (3.785412 L). It translates into 1 part in about 58,000 parts of water or 17.1 parts per million (ppm). Also called Clark degree (in terms of an imperial gallon).
The permanent hardness of water is determined by the water's concentration of cations with charges greater than or equal to 2+. Usually, the cations have a charge of 2+, i.e., they are divalent . Common cations found in hard water include Ca 2+ and Mg 2+ , which frequently enter water supplies by leaching from minerals within aquifers .
Mohs scale of mineral hardness; Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last ... Toggle the table of contents.
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels.
Carbonate hardness, is a measure of the water hardness caused by the presence of carbonate (CO 2− 3) and bicarbonate (HCO − 3) anions. Carbonate hardness is usually expressed either in degrees KH (from the German "Karbonathärte"), or in parts per million calcium carbonate ( ppm CaCO 3 or grams CaCO 3 per litre|mg/L).
Toggle the table of contents. ... Hardness scales may also refer to: Methods of measuring the deposit formation by hard water. The scale of Pencil hardness
Then, the output is translated into the "language" of common use: molar and mass concentrations, alkalinity, buffer capacities, water hardness, conductivity and others. History. Version 1.0 was released in January 2012 (after a half-year test run in 2011). The project is active with 1-2 updates per month.
Degrees of general hardness (dGH or °GH) is a unit of water hardness, specifically of general hardness. General hardness is a measure of the concentration of divalent metal ions such as calcium (Ca 2+) and magnesium (Mg 2+) per volume of water. Specifically, 1 dGH is defined as 10 milligrams (mg) of calcium oxide (CaO) per litre of