Maintenance of dissolved oxygen sensor in aquaculture

    The quality of the water environment plays a crucial role in the aquaculture process. At present, there are two types of detection for the water environment, portable and online. For large-scale and high-density aquaculture, online water quality monitoring is more often used, mainly because online water quality monitoring equipment can real-time understand the changes of various parameters of the aquaculture water. After problems are found, they can be handled in a timely manner to avoid economic losses.

    For aquaculture, dissolved oxygen is one of the more important indicators, which is one of the important conditions for the survival of animals and plants in water. The content of dissolved oxygen in a good water environment must be kept within a certain range, so most of the dissolved oxygen in aquaculture is monitored online through sensors. However, as a consumable, the daily maintenance of dissolved oxygen sensor is very important. Today we will learn some maintenance methods about the dissolved oxygen sensor in aquaculture

Polarization of dissolved oxygen electrode

    When it is used for the first time or restarted after continuous power failure for ≥ 5 minutes, it shall be connected to the instrument and then powered on to balance the chemical system in the electrode and stabilize the electrode. At the beginning, the current of the electrode is large and decreases exponentially. During this period, the displayed data will gradually decrease until it is stable, and then calibration can be carried out.

Calibration of dissolved oxygen electrode

    When the dissolved oxygen electrode leaves the factory, the zero point and slope of the electrode have been calibrated. In the actual use process, the change is very small. Even after the electrolyte or sensitive film is replaced, the zero drift is very small. Normally, when calibrating the electrode, the zero point can not be calibrated, but only the slope, that is, the air calibration.

Maintenance of dissolved oxygen electrode

    1. Filter paper can be used to carefully dry the easily found clogging pollution; For ion pollution that is not easy to be found, the electrode can be removed, soaked with 3% - 5% dilute hydrochloric acid and then used. The soaking time shall refer to the product manual.
    2. In case of mechanical damage, slow response, unstable meter reading drift, and obvious failure to reach zero point and full value during calibration of the sensor, the sensitive membrane shall be replaced.

Performance inspection of dissolved oxygen electrode

    The performance of dissolved oxygen electrode can be qualitatively tested by means of zero oxygen measurement. Take out the electrode first and place it in the air. After the displayed data is stable, record the concentration value. If the concentration value does not coincide with the corresponding value of oxygen concentration in this environment, slope calibration shall be adopted. Place the electrode in an oxygen free medium, and record the concentration value after the displayed data is stable. If the concentration value does not match the zero calibration value, the electrolyte or membrane body shall be replaced.

Replacement of electrolyte and membrane of dissolved oxygen electrode

    1. The electrolyte is strongly alkaline, so contact with skin, mucous membrane and eyes should be avoided. In case of any of the above situations, a large amount of clean water shall be used to wash it quickly. It is recommended to wear safety protection.
    2. The electrode is equipped with membrane and electrolyte when leaving the factory, and has passed the factory inspection, so users can use it directly. If the user does not use it in time, the electrolyte must be replaced according to the manufacturer's regulations.
    3. Replace the membrane body in case of damage, slow response, unstable reading, etc.