5 in 1 MODE: 5 in 1 PH tester, you can accurately measure TDS, EC, SALT, SG, Temp value; Clearly know the water quality to ensure the health of your family members . HIGH PRECISION: With a highly sensitive probe, you can quickly read the results; wide measuring range and high resolution ensure that you can measure different kinds of liquids AUTOMATIC TEMPERATURE COMPENSATION: With ATC function, the 5 in 1 pH meter solves the problem of inaccurate measurement caused by liquid temperature change; Easy to get reliable and stable reading EASY TO USE: After calibration, place the sensor in the solution you want to test and get the data immediately; Before another test, wash the probe thoroughly; Or you may get an inaccurate reading WIDE APPLICATION: The portable water quality tester can be carried anywhere to measure water quality such as tap water, RO system water, aquarium, l sea water, swimming pool water. MODE OF OPERATION: 1. Press ON/OF, open the instrument, remove the protective cap, put it in the solution to be tested, and do not immerse it above the immersion line. Then gently shake it several times in water to remove bubbles around the electrode and read the correct measurement once the value is stable. 2. Press MODE/CAL to enter different models, TDS unit is PPM or PPT, EC unit is uS or mS, salt unit is %, sea water specific gravity unit is S.G. 3. Press HOLD/TEMP and it will display in the upper left corner of the screen, indicating that the value has been held. Then remove the meter from the solution and read the value. Press HOLD/TEMP again to exit hold mode. 4. Press and hold HOLD/TEMP for a long time and the screen will toggle between C and F. TROUBLESHOOTING Startup But No Display The battery is not installed or the battery power is insufficient or not installed correctlyRemove the battery case, reinstall the battery or replace it with a new battery Check whether the positive and negative poles of the battery are correct Unstable Reading Air bubbles attached around the electrode will seriously affect the reading. To reduce air bubbles, fully immerse the electrode and swing in air to remove air bubbles The solution may be asymmetric, resulting in unstable readings The probe is not immersed deep enough in the solution Probe is broken: measure environmental interference.