Always follow the instructions that come with the kit. Here is a summary of the method.

• Rinse the test tube or sample container 3 times with your water sample.
• Fill the test tube to the marked line with your sample water.
• Add 1 Alkalinity #1 tablet. Cap and shake until fully dissolved.
• Add 1 Alkalinity #2 tablet. Cap and shake until the solution turns green.
• Slowly add drops of Alkalinity Titration Reagent (Alkalinity #3), counting each drop. Swirl after each drop.
• Stop when the solution changes from green to pink.
• The number of drops used equals the alkalinity in ppm (parts per million) as CaCO₃.

Note: Record the number of drops used and the final colour change. If unsure about the colour shift, take a photo to compare or repeat for accuracy.