3 in 1 reliably measure TDS, EC, and temperature. Three different measurement requirements can be met with 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 above 40) indicates higher TDS levels, while the green backlight (ppm below 40) indicates lower TDS levels suitable for filtered drinking water. Note: A TDS level of 40 is commonly used as a reference point for filtered water. The ppm meter features simple button operation—turn it on and dip the meter into water. The water hardness meter is built to high standards of quality and reliability. We are confident in the performance and durability of our water test meter.