Phosphate test

Phosphate test is to determine the amount of excess phosphate present in the boiler treatment feedwater. A measured amount of boiler water is poured into a mixing tube and molybdate is added. The tube is then stoppered and vigorously shaken. The next step is to add dilute stannous reagent, which has been freshly prepared from concentrated stannous reagent and distilled water, to the mixture in the tube. This will produce a blue color and lightness or darkness of the blue indicate the amount of phosphate in the boiler water. The tube is compared with standard colored glass slides, which marked in amounts of phosphate