1. Gently pull out the black plate with the switch on the pen, do not pull the wire, you can see 4 1.5V batteries, just pull out and replace;
2. Pay attention to the battery polarity and choose the same type of battery;
3. When the electrode is inserted into the test solution or calibration buffer, it should not exceed the maximum height marked on the test pen.
4. If the electrode is placed for a long time and the sensitive bulb is exposed to the air, the response will be slow and the displayed value will be unstable due to the drying of the electrode. At this time, the electrode should be activated by immersing it in distilled water for several hours;
5. To improve performance, insert the pH meter electrode into distilled water at least once a week for a few minutes each time;
6. Protein precipitates (such as milk, cheese, etc.) should be immersed in pepsin and hydrochloric acid solution for elimination; this solution is prepared before use, after use, immerse the electrode in this solution for several hours, and then rinse with water Rinse well, then immerse in distilled water for several hours;
7. The grease film also affects the measurement of the sensitive bulb. Li removed the film, rinsed the sensitive bulb with 75% alcohol solution, dried it with filter paper, rinsed with water, and then immersed it in distilled water for several hours.
