Total hardness test set, model HA-71A

Description

Water hardness is almost entirely caused by calcium and magnesium ions. Other divalent and trivalent metals have a similar effect, but usually the concentration in drinking water is not high enough to cause problems. Hardness increases soap consumption in laundries and causes limescale to build up in boilers and pipes.

With the HA-71A Hach Lange test kit, simply count the number of drops required to change the color of the solution to determine the total water hardness concentration. Using the drop count titration method, this kit provides a double measuring range and contains about 100 tests.

Instructions for the determination of hardness in the low range (from 1 to 20 mg/l CaCO3)

• Fill the flask with sample up to the 100 ml mark.
• Add 2 ml Buffer Solution 1 to the flask. Rotate to mix.
• Add four drops of Hardness Indicator 2. Rotate to mix. Blue indicates soft water. If red appears, go to step 4.
• Add Hardness 3 reagent drop by drop. Count the drops until the color changes from red to blue. Shake to mix each drop.
• Count the results. Each drop of Hardness 3 Titration Reagent is 1 mg/L Calcium Carbonate (CaCO3).

Instructions for determining the hardness in the high range (from 17 to 342 mg / l CaCO3)

• Fill the plastic measuring tube to the top with the sample. Pour the sample into a bottle.
• Add three drops of Buffer 1 to the mixing container. Rotate to mix.
• Add one drop of Hardness Indicator 2 to the mixing container. Rotate to mix. Blue indicates soft water. If red appears, go to step 4.
• Add Hardness 3 reagent dropwise. Count the drops until the color changes from red to blue. Shake to mix each drop.
• Count the results. Each drop of Hardness 3 titration reagent corresponds to a hardness of 1 grain per gallon of calcium carbonate (CaCO3) = 17.1 mg/L.