When using the reference electrode, the rubber plug of the small hole on the upper end of the electrode should be opened, and the liquid level inside the electrode should be higher than the liquid level of the measured solution.

When using the 2.217 double salt bridge reference electrode, the inner and outer salt bridge solutions can be prepared and added as needed.

3. The solution inside the electrode should not have bubbles to prevent circuit breaking.

4. If crystals are attached to the surface of the electrode, they should be washed away with distilled water to avoid bringing in the measured solution and affecting the measurement accuracy.