3 in 1 reliably measures TDS, EC, and temperature. This meter meets three different measurement requirements in one device. Equipped with a high-quality titanium alloy probe, the TDS water quality tester provides quick and convenient testing. Suitable for drinking water, swimming pools, laboratories, plants, aquariums, well water, and more. Features a large backlit LCD display. The red backlight (TDS over 40 ppm) indicates higher mineral content, while the green backlight (TDS below 40 ppm) indicates lower mineral content, which is typical for filtered drinking water. Note: 40 ppm is commonly referenced as a general guideline for filtered water. The ppm meter features simple button operation—turn it on and immerse the probe into water. This water hardness meter is built to high standards of quality and reliability. We stand behind the performance and durability of our water test meter.