WATER TREATMENT BEFORE STOCKING
Water treatment for shrimp farming is an indispensable step. Without the best conditions, shrimp will be susceptible to disease, slow growth, and development.
Reservoirs are twice as large as grow-out ponds, and 0.5 - 1m as deep as grow-out ponds. They are used to store clean water. Pond bottoms must be plowed, limed, and cleaned. Water before being pumped into the grow-out pond should be filtered through a fine mesh to get rid of trash and reject natural shrimp and fish. Then, it is processed in reservoirs to remove impurities, harmful organisms to the development of shrimp.
In aquaculture, farmers should rehabilitate and pump water into the reservoirs before renovating grow-out ponds for 20-30 days. Water is filtered through the net and allowed to settle for 10-20 days to ensure that the organic matter has enough time to decompose into nutritional salts for algae growth and reduce the density of pathogenic bacteria. To accelerate this process, providing more oxygen by aerators is necessary. The longer the sedimentation process is, the more effective it is to prevent Early Mortality Syndrome (EMS) conditions. If there is no reservoir, the grow-out pond can be replaced as a settling pond.
When transferring water from reservoirs to grow-out ponds, it must be pumped through a filter bag with poly cotton fabrics to eliminate predators, competitors, or intermediate hosts carrying pathogens such as crabs, shrimp, pulp, etc., and determine the salinity to report to the postlarvae hatchery if needed. The ideal pond water level for shrimp and environment stabilization is 1.3 - 1.4 m.
In about 3 days, the aerators must run continuously to make the fish eggs and crustaceans fully hatched and then kill them with tea pulp (saponin), fish medicinal plant roots (rotenone), or specialized chemicals. The most effective time of saponin is from 4 - 6 a.m. In case that the salinity of pond water is lower than 10 ppt, or there is a lot of goby, perch, and snakehead fish in the pond, you should increase the dose. Please take note, you need to soak the saponin in water for about 12 hours before using it. The best time to stock postlarvae is 3 days after killing impurities. If the biocide only contains natural saponins, no harmful chemicals are added, the fish will die after about 3-4 hours.
For the treatment of turriform or bottom seaweed, copper sulfate (CuSO4) can be used with a treatment concentration of 2 - 3 ppm.
Bacteria killing should be implemented 2 days after impurities killing to eliminate pathogens in pond water. Chlorine, TCCA, BKC, potassium permanganate KMnO4, Formol, Iodine, or PVP-Idodine are currently the most commonly used disinfectants. Chlorine is most commonly used with treatment doses of 25-30 ppm if the water pH is <7.5. This dosage can be increased or decreased depending on the amount of organic matter present in the water and the pH of the water. The higher the pH, the more organic matter content, the higher the treatment dose of chlorine needed.
Please take note, the effects of potassium permanganate and formol can adversely affect the health of the users. Farming areas with acute hepatopancreatic necrosis disease, also known as Early Mortality Syndrome (EMS/AHPND) should use BKC with a dose of 0.3 ppm.
Culture green water
To culture green water, farmers can apply different methods of water treatment such as fertilization, the density of algae maintenance, and a natural food source creation. After culturing green color, you should check the transparency of pond water before stocking.
During shrimp farming, the water in the pond can be contaminated. It is necessary to ensure the best water quality for shrimp growth. You should change the water in the ponds regularly until the end of the season.
Green solutions provides products that support water treatment prior to the aquaculture process. All of them are imported directly from the developed countries that apply the result of international advanced technology in aquaculture products to ensure high value and efficiency as well as commit to protecting the environment.
According to: contom.vn