Getting Started

First Use Notes

The pH sensor is rigorously calibrated before leaving the factory and is ready for use upon arrival, requiring no further calibration.

Handling the Probe

The bottle cap of the probe contains protective liquid (3.3mol/L KCL). Even if the bottle cap is screwed tightly, some protective liquid may still leak around the bottle cap, forming white crystals. But as long as there is still protective liquid in the bottle cap, it will not affect the life and accuracy of the probe. So please use it with confidence. It is recommended that the white crystals be poured back into the protective liquid in the bottle cap.

The protective bottle at the electrode tip contains an appropriate amount of soaking solution. Immerse the electrode tip in this solution to maintain the activation of the glass bulb and liquid junction. Before measurement, loosen the cap, remove the electrode, and rinse with pure water.

Installation Methods

1. Submersible Installation: The sensor lead wires emerge from the waterproof conduit, and the top 3/4 thread is connected to the waterproof conduit's 3/4 thread using Teflon tape. Ensure the top of the sensor and the wires are not wetted.
2. Pipe Installation: Connect the sensor to the conduit via its 3/4 thread.

Electrode Calibration Instructions

1. The sensor uses two-point calibration. Prepare two standard buffer solutions with different pH values. For acidic solutions, use standard buffer solutions with pH values ​​of 4.01 and 6.86; for alkaline solutions, use standard buffer solutions with pH values ​​of 6.86 and 9.18; for general applications, use standard buffer solutions with pH values ​​of 4.01 and 9.18.

2. At room temperature (around 25°C), immerse the pH electrode in a standard buffer solution with a relatively lower pH value (e.g., choose 4.01 when using both 4.01 and 9.18 buffer solutions). After the readings stabilize, input the command to perform the first-point calibration (see the communication protocol example for detailed commands).

3. After the first calibration is completed, clean the pH electrode and dry it with a paper towel or soft cloth (do not damage the glass bulb of the electrode, otherwise the electrode will fail). Place the sensor in a standard buffer solution with a relatively high pH value (for example, choose 9.18 when using two buffer solutions, 4.01 and 9.18). After the value stabilizes, input the command to perform the second calibration (for detailed commands, please refer to the communication protocol example).

Precautions and Maintenance (Advanced)

◆ The equipment itself generally requires no routine maintenance. In case of obvious malfunction, please do not attempt to repair it yourself; contact us immediately!
◆ The glass bulb at the electrode tip must not come into contact with hard objects. Any damage or scratches will cause the electrode to malfunction.
◆ Before measurement, remove air bubbles from the electrode bulb; otherwise, the measurement will be affected. During measurement, stir the electrode in the solution to be measured and then let it stand still to accelerate the response.
◆ Clean the electrode with deionized water before and after measurement to ensure accuracy.
◆ After long-term use, pH electrodes may become passivated, resulting in a reduced sensitive gradient, slow response, and inaccurate readings. For non-metallic electrodes: Soak the lower bulb in 0.1M dilute hydrochloric acid for 24 hours (0.1M hydrochloric acid preparation: dilute 9 ml of hydrochloric acid with distilled water to 1000 ml), then soak in 3.3M potassium chloride solution for 24 hours. If the passivation of the pH electrode is severe and soaking in 0.1M hydrochloric acid has no effect, immerse the bulb end of the pH electrode in 4% HF (hydrofluoric acid) for 3-5 seconds, rinse with pure water, and then soak in 3.3M potassium chloride solution for 24 hours to restore its performance. For antimony electrodes: The metal tip can be polished with fine sandpaper until a metallic luster appears, restoring its performance.
◆ Contamination of the glass bulb or blockage at the liquid junction can also cause electrode passivation. In this case, cleaning with an appropriate solution should be used according to the nature of the contaminant, as detailed in the table below (for reference).

◆ The electrode's service life is 6-12 months. Replace the electrode promptly after aging.
◆ The equipment should be calibrated before each use. For long-term use, calibration every 3 months is recommended. The calibration frequency should be adjusted appropriately according to different application conditions (degree of dirt in the application environment, chemical deposits, etc.).

Preparation of Electrode Soaking Solution

Dissolve one packet of pH 4.00 buffer in 250 ml of pure water, then add 56 g of analytical grade potassium chloride. Heat appropriately on an electric furnace, stirring until completely dissolved. Alternatively, a 3.3M potassium chloride solution can be used for soaking, prepared as follows: Dissolve 25 g of analytical grade potassium chloride in 100 ml of pure water.