Water Hardness Test Kit
Essential when configuring a water softener to determine the level of hardness in the incoming water supply. Simply add the drops to a 10mm sample in the tube, each drop counts for 20ppm of hardness. Add the drops, shaking after each is added until the colour changes from red to blue. Multiply the number of drops by 20 to get the total hardness in ppm (parts per million) or mg/l (milligrams per litre).