Water test for measuring temporary hardness KH (German degrees) in fresh and marine water aquarium. The optimal value in fresh water aquarium is about 4°, in marine water aquarium goes from 8° to 10°.


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 time of reagent contained in the bottle and gently swirl to mix the solution after every drop. COUNT the number of drops until the solution turns from light yellow to a red-purple colour.

3. Once the solution has turned red-purple leave it to stand for 30 seconds. If the colour disappears, add more drops of reagent until the solution remains this red-purple colour.

4. Temporary water hardness is given in German degrees (°dKH) and corresponds to the number of drops of reagent utilized to obtain the red-purple colour. 1 drop = 1°dKH.

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.