Hardness is a measure of the mineral content of water. Calcium and magnesium are the most common minerals that contribute to hardness. Hard water causes scaling in boilers and other industrial equipment, and diminishes the effectiveness of soaps and detergents.
The EDTA Method (Total)
References: APHA Standard Methods, 23rd ed, Method 2340 C- 1997. USEPA Methods for Chemical Analysis of Water and Wastes, Method 130.2 (1983).
The total hardness method is applicable to drinking, surface, boiler, and brine waters. The EDTA titrant is employed in alkaline solution with a calmagite indicator. This method determines the combined calcium and magnesium concentration of a sample. If no magnesium is present, the end point of the titration normally appears sluggish. Results are expressed as ppm (mg/L) CaCO3.
Range: 100-1000 ppm as CaCO3
MDL: 100 ppm
Method: EDTA (total)
Increments: 100, 110, 120, 130, 140, 150, 160, 180, 200, 250, 300, 350, 400, 500, 700, 1000 ppm
Kit comes in a cardboard box and contains everything needed to perform 30 tests: thirty ampoules with valve assemblies, titrettor, 25 mL sample cup, and instructions.