Features: Automatic calibration: The TDS meter has automatic temperature compensation that adjusts for water temperature and water quality, providing a TDS reading almost instantly. Wide use: Suitable for testing TDS value in drinking water, swimming pools, aquariums, spas or hydroponics. How to use: First remove the pen cover, turn on the ON/OFF switch 2. Insert the probe into the water, the water level is below the probe, stir gently 3. Wait for the reading to be stable and read the data 4. Press the TEMP button to enter the temperature measurement mode, then press Switch TDS mode once. High-sensitivity alloy probe: Anti-corrosion and anti-rust, accurate test and sensitive response. Power supply: Powered by a button battery, it is easy to replace the battery, durable, and needs to be recalibrated after replacing the battery. Note: 1. When the measured value is greater than 999, it will be displayed as X10. 2. The TDS value is affected by water temperature, water flow rate and water pollution, and the error is 2%-3% of the measurement range. 3. Measuring water temperature