Water hardness test is a fast, simple and effective way to measure water hardness yourself.
This way we can know the hardness of our water, something that is necessary for the selection of the right softening system but also for its regulation and the control of the correct operation. 
This particular set measures the hardness of water in german degrees.

How to use: 

The set consists of a 15ml liquid bottle and a test tube. Fill the test tube with water that we want to measure, up to 5ml. Then we start and drop in the water one by one a drop of the liquid. The water in the test tube will turn red. Continue to add drops of liquid until the water turns red-green. Then we stop and count how many drops of liquid we dropped until the water turns green. The more drops we drop, the more degrees of hardness our water has. If, for example, we drop 16 drops, then our water has 16 german degrees of hardness.

1 german grade = 1.79 french points