Dissolved oxygen refers to the oxygen molecules dissolved in water. Its content is affected by various factors, including water temperature, pressure, and salinity. In aquaculture, the content of dissolved oxygen needs to be measured constantly. Aquatic organisms rely on dissolved oxygen for their survival and growth. When the dissolved oxygen content in water is lower than 4mg/L, the growth of most fish will be inhibited. When it is lower than 2mg/L, it may lead to the death of fish. Measuring dissolved oxygen can help us understand the oxygen condition in water in a timely manner and avoid the hypoxia of aquatic animals. Meanwhile, dissolved oxygen is also an important indicator of water quality. Its content can reflect the degree of water pollution. Sufficient dissolved oxygen is beneficial to maintaining the ecological balance and self - purification ability of water bodies.
A dissolved oxygen sensor is an instrument that can monitor the dissolved oxygen content in water bodies in real - time and continuously. Taking the fluorescence - method dissolved oxygen sensor as an example, it works based on the principle of fluorescence quenching of specific substances. When the excitation light irradiates the fluorescent substance on the surface of the fluorescence membrane head, the fluorescent substance is excited to emit light. The luminescence lifetime is affected by the concentration of oxygen molecules. The concentration of oxygen molecules is calculated by detecting the luminescence lifetime, and the final value is obtained through temperature, pressure, and salinity compensation. It has many advantages, such as high measurement accuracy, good stability, fast response, and easy daily maintenance.
The FT - S8 fluorescence - method dissolved oxygen sensor has a measurement range of 0 - 20mg/L, a resolution of 0.01mg/L, and an accuracy of ±2%, ±0.3℃. It can automatically perform temperature compensation. It has output methods such as RS - 485 (Modbus/RTU) and 4 - 20mA, which are convenient for integration with various devices. It has strong adaptability to the working environment and can work stably in the environment of 0 - 50℃ and <0.3MPa. Its protection level is IP68, and the calibration method is two - point calibration. It is small in size, with a length of 170.2mm and an outer diameter of 30mm. It is easy to install, and its service life is about one year. The daily maintenance mainly includes wiping the dirt on the outer surface.
In aquaculture, the FT - S8 can monitor the dissolved oxygen content in water bodies in real - time, and provide timely feedback data. This enables farmers to accurately grasp the water quality situation, adjust and control the aquaculture environment, ensure the healthy growth of aquatic organisms such as fish and shrimp, and improve the aquaculture efficiency.
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