Water hardness is the traditional measure of the capacity of water to react with soap, hard water requiring considerably more soap to produce a lather. Hard water often produces a noticeable deposit of precipitate (e.g. insoluble metals, soaps or salts) in containers, including “bathtub ring”. It is not caused by a single substance but by a variety of dissolved polyvalent metallic ions, predominantly calcium and magnesium cations, although other cations (e.g. aluminium, barium, iron, manganese, strontium and zinc) also contribute. Hardness is most commonly expressed as milligrams of calcium carbonate equivalent per litre. Water containing calcium carbonate at
concentrations below 60 mg/l is generally considered as soft; 60–120 mg/l, moderately hard; 120–180 mg/l, hard; and more than 180 mg/l, very hard (McGowan, 2000). Although hardness is caused by cations, it may also be discussed in terms of carbonate (temporary) and non-carbonate (permanent) hardness
Water hardness calculator
There are two types of water hardness. Temporary and permanent hardness. This calculator determines the permanent total hardness. For information about the temporary water hardness click here.
Total permanent water hardness is calculated with the following formula
TOTAL PERMANENT HARDNESS = CALCIUM HARDNESS + MAGNESIUM HARDNESS
The calcium and magnesium hardness is the concentration of calcium and magnesium ions expressed as equivalent of calcium carbonate. The molar mass of CaCO3, Ca2+ and Mg2+ are respectively 100,1 g/mol, 40,1 g/mol and 24,3 g/mol
Calcium and magnesium
Calcium and magnesium dissolved in water are the two most common minerals that make water “hard.” The degree of hardness becomes greater as the calcium and magnesium content increases and is related to the concentration of multivalent cations dissolved in the water.
what is calcium hardness in water
Calcium hardness is a measure of the amount of calcium ions present in the water. … These minerals are largely made up of calcium and magnesium carbonates, bicarbonates, chlorides or sulfates. The minerals mostly get into the water by washing over or through limestone and chalk rocks.
what is magnesium hardness in water
Water should have a total hardness of less than 75 to 85 mg/l as CaCO3 and a magnesium hardness of less than 40 mg/l as CaCO3 to minimize scaling at elevated temperatures. Many systems allow hardness in finished water to approach 110 to 150 mg/L to reduce chemical costs and sludge production