5-in-1 pH Tester: The tester can measure pH, salinity, EC, TDS and temperature. Simply press the button (MODE/CAL) to switch and read values between pH, salinity, EC and TDS. By long pressing the HOLD/TEMP button, you can switch between temperature degrees and Celsius degrees. Used for daily monitoring of water quality, so you can know the water quality at any time. Automatic Temperature Compensation: The pool pH meter does not need to consider the temperature of the liquid to be measured. This instrument can make accurate measurements over a temperature range of 0°C to 60°C (32°F to 140°F), which solves the problem of inaccuracies due to variations in liquid temperature. Whether you are in winter or summer, you can get accurate values. User-friendly design: The backlight on this EC tester allows you to see data clearly even in low light. The HOLD/TEMP button can be used to lock the reading, and the backlight turns off within 30 seconds. Press any button to turn the backlight on again. Easy Calibration: The swimming pool tester supports 3-point automatic calibration and can be easily calibrated automatically to 4.01, 6.86 and 9.18 according to the instructions. The unit has been calibrated at the factory and is ready to use upon receipt. If recalibration is necessary, you no longer have to worry about finding the calibration solution (the box is equipped with a calibration kit). Has many uses: The TDS meter for aquarium can measure salt water, used in swimming pools, spas, aquariums, aquaculture; The pH EC meter can measure EC and pH in hydroponic crops. TDS and pH meters can measure liquids such as permeate water, drinking water, tap water, coffee, fruit juice, brewed wine and beer.