1. Rinse the water sample test tube several times with the water to be tested and then fill with sample water to the 5 ml mark.
2. Add one drop at a time of the reagent contained in the bottle and gently swirl to mix the solution after every drop. COUNT the number of drops until the solution turns green.
3. Once the solution has turned green leave it to stand for 30 seconds. If the colour disappears, add more drops of reagent until the solution remains green.
4. Total water hardness is given in German degrees (°dGH) and corresponds to the number of drops of reagent utilized to obtain the green colour. 1 drop = 1° dGH. CAUTION: Thoroughly clean the test tube after use, securely seal all reagent containers and store in a cool, dry place away from sunlight. Keep the product out of reach of children.