Description

Operation

• Fill the pipette to the 10 ml mark with sample.
• Add the water to the clean flask.
• Add contents of one Low Hardness (I) reagent to the flask and swirl to dissolve. A blue color indicates the hardness is 0 mg/L. If a red color develops, proceed to step 4.
• Fill the titration pipette with 1 mL of Low Hardness (II) reagent.
• Add the reagent slowly and swirling untill untill the color changes from red to blue. If 1 mL is not enough, repeat step 4 & 5. Read off the measurement value (V, mL) from the pipette.
• Calculate the results. Hardness = V x 20 (mg/L, as CaCO3).

Notes

• Rinse flask with deionized water before the test.
• The pH must be within the range 6-9. Adjust if necessary, with NaOH or HCl.
• When pipetting, if there are air bubles in the pipette, pull and push the piston repeatedly with the suction port immersion in the liquid.