Product Short Description: Calcium and magnesium present in a water sample is determined, by giving the greatest color change as the end point. Product Description: Amount of calcium and magnesium present in a water sample is determined. The determination of the hardness of water is important in water treatment plants. RXSOL-60-6232-100 is standarised and caliberated solution of colour indicator, which will help for determination of HARDNESS standard by giving the greatest color change as the end point.