Digital 0.0-14.0 PH Meter Tester 0-9990ppm &EC LCD Water Purity PPM Aquarium
0-50: high purity. 50-100: high purity. 100-300: for general purity. [Living] - Take care of your family's health, good water makes them healthier. 300-600: will form the scale. Place the pen in the solution to be tested.