5 in 1 pH Tester: The tester can measure pH, salinity, EC, TDS and temperature. Simply press the (MODE/CAL) button to switch and read the values between pH, salinity, EC, and TDS. Long press the HOLD/TEMP button to switch between temperature and Celsius. Used for daily water quality monitoring, allowing you to know the water quality status at any time. Automatic Temperature Compensation: The pool pH meter does not need to take into account the temperature of the liquid to be measured. This instrument is capable of accurate measurements over a temperature range of 0°C to 60°C (32°F to 140°F), which solves the problem of inaccuracy due to liquid temperature fluctuations. Whether you are in winter or summer, you can get accurate values Human-scale design: The backlight function of this ec tester allows you to see the data clearly even in low light conditions, The HOLD/TEMP key can be used to lock the reading, and the backlight will turn off within 30 seconds, Press any key to turn on the backlight again Easy calibration: The pool tester product supports 3-point automatic calibration, can be easily automatically calibrated to 4.01, 6.86 and 9.18 according to the instruction manual. The device has been factory calibrated and is ready to use upon receipt. If recalibration is needed, don't worry about finding the calibration solution (the box is equipped with a calibration kit) Widely used: Aquarium TDS meters can measure salt water, used in swimming pools, SPAs, aquariums, aquaculture; pH EC meter can measure EC and pH of hydroponic crops. TDS and pH meters can measure liquids such as permeate water, drinking water, tap water, coffee, fruit juice, brewed wine and beer