Operation Steps: # Remove the protective cover. # Clean the electrode with water (there is white crystalline salt around the electrode cap. It is a normal phenomenon of the pH electrode. As long as the electrode is immersed in water, it dissolves and disappears). #. Turn on the switch. Insert the pH meter into the measured liquid until the liquid is submerged to a slight immersion, allowing the solution to soak slightly above the immersion line. # Gently stir until the displayed value is stable, then read the displayed value. The pH meter must be recalibrated in the following cases: 1. Has been used (or placed) for a long time after calibration. 2. Particularly frequent electrode use. 3. High measurement accuracy. Operating Temperature: 0 - 50°C (32 - 122°F)