Description

Operation

• Fill the pipette to the 10 ml mark with sample.
• Add the water to the clean flask.
• Add contents of one Total Hardness (I) (LR) 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.
• With swirling add the Total Hardness (II) (LR) reagent drop by drop untill the color changes from red to blue, Count the number of drops (N).
• Calculate the results. Total Hardness = N x 10 (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.