3 in 1 reliably measure TDS, EC, and temperature. Three different measurement requirements can be met by one meter. Equipped with a high-quality titanium alloy probe, the TDS water quality tester allows for quick and convenient testing. Suitable for drinking water, swimming pools, laboratories, plants, aquariums, well water, and more. Water hardness tester features a large backlit LCD. The red backlight (ppm number over 40) indicates higher TDS levels. Green backlight (ppm number below 40) indicates lower TDS levels suitable for filtered drinking water. Note: A TDS level of 40 is commonly used as a reference point. The ppm meter allows simple button operation—turn it on and dip the meter into water. The water hardness meter is manufactured to high standards of quality. We have confidence in the performance and reliability of our water test meter.