Taylor Reagent Pack, Buret, Hardness (calcium/total), EDTA, 1 mL = 1 mg

Taylor Reagent Pack, Buret, Hardness (calcium/total), EDTA, 1 mL = 1 mg

In buret titrations, a solution of known concentration is added gradually from a buret to either a solution of a weighed quantity of unknown material or to a precisely known volume of solution of the unknown material. Addition is continued until the exact mole ratio required by the balanced chemical equation is reached. This point is called the “equivalence point” of the titration and is usually detected through the addition of an indicator to the solution being titrated.

Hardness in water was originally defined as the ability of soap to lather in water—the more calcium and magnesium ions, the “harder” it is for soap to form suds. Although other polyvalent cations also precipitate soap, they are often in complex forms, frequently with organic constituents, and have a minimal effect on water hardness. Today, total hardness is considered to be the sum of the calcium and magnesium ions present in water, expressed in milligrams per liter (mg/L) or parts per million (ppm) as calcium carbonate (CaCO3). The amount of hardness in water can range from several parts per million to hundreds.

In industrial boiler applications, hardness is removed from water by pretreatment equipment such as softeners, demineralization units, and reverse osmosis. Treatment chemicals are then applied to the water to prevent any low-level residual hardness from causing deposition problems. In industrial cooling tower water applications, hardness increases in concentration as the water cycles up due to evaporation. Treatment chemicals are often applied here, also, to prevent any scale deposits.

Wherever it occurs, scale reduces operating efficiency and can lead to premature equipment failure; therefore, it is critical to test hardness levels regularly. Taylor offers several test kits for hardness in sensitivities which range from trace to high-hardness concentrations. All of these kits include metal-interference inhibitors.