What water quality monitoring instruments are needed for aquaculture？

In the context of the upgrading of the fishery industry, it is necessary to increase the scale and mode of breeding of high value-added species by adjusting the structure and promoting upgrading. Use intelligent monitoring and management to realize the environmental regulation of breeding waters, increase the density of famous, special and high-quality aquaculture, and realize the transformation of industrialized aquaculture.

   The main content of factory aquaculture is to establish a closed aquaculture plant with water circulation, and monitor and control the aquaculture water through a series of chemical, physical and biological means to create the most suitable water environment for fish growth. The key to realizing factory farming is the water circulation treatment and control system, which controls the water temperature, pH, ammonia nitrogen (ammonium ions), COD, DO dissolved oxygen and other important water quality parameters.

   Online instrument for breeding water quality monitoring: ammonia nitrogen, temperature, dissolved oxygen, pH value, turbidity, etc. Using online monitoring technology, it can be automatically adjusted in time to ensure that the aquaculture water meets the growth requirements of fish. The automatic control of these parameters is very important for factory aquaculture, and some are controlled by biological methods, such as the use of biological filters to transfer other ammonia nitrogen through nitrification. Such parameters can be monitored and accurately controlled, which can fully reflect the factory Advantages of chemical aquaculture.

1. Temperature control (temperature analyzer)

   Different fish are suitable for different growth temperatures. Under the best temperature, fish grow fast, have high feed conversion efficiency, strong physique, and strong ability to resist fish diseases. The efficiency of the biological filter is also related to temperature. Too low temperature will affect the conversion efficiency of ammonia nitrogen. In the process of cold-water fish breeding, the influence of temperature must be considered, but in warm water aquaculture, temperature is not the main factor affecting ammonia nitrogen. (Such as salmon farming, temperature is very important.)

2. Dissolved oxygen control (dissolved oxygen analyzer)

   A large amount of oxygen is required in the water body of industrial aquaculture. Fish need oxygen for physiological activities. Each ton of fish consumes 3 kg of oxygen per day. Biofilters need oxygen to convert ammonia nitrogen. If 1 kg of ammonia nitrogen is discharged per ton of fish per day, 4.75 kg is consumed. Oxygen: More than 7.57 kg of oxygen is consumed directly and indirectly every day, so continuous supply of sufficient dissolved oxygen (DO) for fish and biological filters is a necessary condition for the normal operation of the water circulation treatment system. In order for the fish to grow as fast as possible, the DO parameter should be kept above 60% of the water body's DO saturation or above 5ppm. .

   In the process of aquaculture, the dissolved oxygen changes at different times. For example, after feeding, the digestion of food by fish will rapidly reduce the amount of dissolved oxygen. At this time, it is necessary to control the air pump to increase the amount of aeration to ensure the amount of dissolved oxygen. When the demand for dissolved oxygen decreases, the amount of inflation must be reduced to reduce the inflation time and reduce energy consumption. Therefore, automatic monitoring of dissolved oxygen and timely control of oxygen increase are very necessary.

   The automatic control process of dissolved oxygen is as follows: The dissolved oxygen sensor placed in the water detects the dissolved oxygen in the water and outputs it to the inverter. The frequency converter changes the current frequency according to the received control result, thereby controlling the increase and decrease of the motor speed of the air pump or aerator, and change the amount of air inflated to meet the requirements of dissolved oxygen.

3. Ammonia nitrogen control (ammonium ion-ammonia nitrogen analyzer)

   Nitrogen is an essential macro element for algae, and it is also a common nutrient element that restricts primary production in aquaculture waters, which has a great impact on production. In the water body of artificial aquaculture ponds, nitrogen exists in the form of molecular nitrogen (N2), inorganic nitrogen (NH3, NH4+, NO2-, NO3-) and organic matter (such as urea, amino acids, and protein). Under the influence of biological, non-biological and human factors, they are constantly transforming and migrating in the water body, and they are constantly undergoing dynamic cycles. Among them, the presence of nitrogen in water with NH3 and NH4+ ions has the greatest impact on production. NH3 and NH4+ are essential nutrients for algae. Almost all algae can directly, quickly and preferentially use NH3 and NH4+. The disadvantage is that the presence of ammonia nitrogen inhibits the utilization of nitrite nitrogen (NO2-) and urea by algae; and ammonia nitrogen consumes dissolved oxygen in water, especially in molecular form, in the process of converting ammonia nitrogen into nitrate. Ammonia (NH3) is very toxic to fish and other aquatic animals. Even if the concentration is very low, it can inhibit growth, damage gill tissue, aggravate fish diseases, and cause adverse effects on breeding and production. The main source of ammonia nitrogen in pond water is the decomposition of nitrogenous organic matter in pond water and bottom sludge and the metabolism of aquatic organisms. Especially in high-input, high-yield ponds, artificial large amounts of bait and fertilization increase the amount of nitrogen-containing organic waste in the pond; the density of stocking is high, the biological metabolism is strong, and the amount of waste ammonia excreted increases. The increasing rate of ammonia greatly exceeds the phytoplankton utilization limit, so that ammonia accumulates in the water.

   In the process of aquaculture, the by-product of protein digestion is ammonia nitrogen, which can produce about 2.2 pounds of ammonia nitrogen per 100 pounds of feed. Ammonia nitrogen exists in water in two forms, one is ionic (NH4+) and the other is non-ionic ( NH3), non-ionic ammonia nitrogen is extremely toxic to fish, it must be converted or removed.

4. pH control (online pH analyzer)

   Microbial treatment to remove ammonia nitrogen in aquaculture water is a commonly used economical and effective method, that is, to establish a biologically active filter, and nitrification reaction is carried out on the biofilm formed in the biological filter, which can convert the toxic substance ammonia nitrogen in the water It is less toxic nitrate and discharged from the water body to achieve the purpose of removing ammonia nitrogen. The nitrification process mainly relies on nitrifying bacteria, and the number of nitrifying bacteria is related to the effect of removing ammonia nitrogen. Experiments have shown that the pH value directly affects the number of nitrifying bacteria and denitrifying bacteria, and the alkaline water quality is conducive to the growth of nitrifying bacteria. When the pH value is 7.5, the ammonia nitrogen removal effect can meet the existing factory farming requirements for non-ionic ammonia ≤ 0.05 mg/L, nitrite ≤ 1 mg/L, and nitrate ≤ 200 mg/L. 

 Benefits of aquaculture instruments

   There are three methods for real-time monitoring of fishery and aquaculture water environment, namely basic on-site control, professional on cloud wireless transmission control, and industrialized system management (on-site display instrument: single parameter pH, temperature, dissolved oxygen, ammonia nitrogen ammonium ion or multiple options according to needs Parameter aquaculture instrument).

   The implementation can start from an on-site system, and increase to a cloud-based professional as required. When a certain number of fish farming units are used in an administrative area, the fishery authority can coordinate and upgrade to an industrialized system management type.

   The application of this technology will be a revolution in aquaculture technology, completely changing the past history of farming based on personal experience. Through quantitative digital management of the aquaculture environment, the scientific nature of aquaculture is improved.

1. Through the control of the water body, the stocking density was increased reasonably to achieve a 30% increase in production.

2. Reduce manual use and labor intensity, increase labor productivity, and reduce costs by 20%.

3. Energy saving and emission reduction, measurement and control, so as to increase oxygen, feed, reduce bait feed, save water change times and power consumption by 50%.

4. Improve product quality, reduce fish diseases, and increase income by 10%.

   Using this new technology, the annual comprehensive income will be increased by more than 30%. The input cost can be recovered in 1-2 years. It is a revolutionary new technology application worthy of promotion.