One is to clear the bottom sludge. The main components of sludge are large amounts of residual baits, organic matter, dead bodies and biological excretions. Excessive sludge will easily lead to deterioration of water quality, and will also produce large amounts of organic acids, hydrogen sulfide, ammonia, etc., which will reduce the value of pool water, inhibit and threaten the growth and survival of crabs, especially pathogenic microorganisms such as harmful bacteria and parasites. Exist in silt. Once conditions are right, various pathogens are flooded. The second is to freeze the bottom of the pool. After the crab pool is cleaned up, clear the ditch and pump it regularly with machinery to try to make the bottom of the pool go through freezing cold and sunlight for about a month to improve the soil conditions at the bottom of the pool so that some pathogens can be killed by freezing and exposure to sunlight. For the growth of crabs in the future to create a good ecological environment. The third is to build a drainage system. In addition to taking into account adequate water flow, water physical and chemical factors consistent with the growth of crabs, free from contamination and pathogens, we must also pay attention to the mutual infection and re-infection caused by the same canal used for drainage and drainage. Therefore, it is required that each crab pool be independent. The pool will be drained. Fourth, drug disinfection. 20 days before the stocking of crabs, strict disinfection with quicklime, bleaching powder, etc., quicklime disinfection with 75 kg -100 kg per acre, the whole pool of calcined water spilled, bleaching powder disinfection with 15 kg per kg-20 kg. The fifth is to do a good crab disinfection. Before the crabs go down the pond, disinfect with the appropriate drugs. Conveniently soak in potassium permanganate 15 mg-20 mg per liter for 20 minutes to 30 minutes, or soak for 10 minutes to 15 minutes with 10 mg of bleach solution per liter. The sixth is to transplant aquatic plants. Aquatic plants can provide habitat for river crabs, and the clam shell environment can also provide fresh and delicious plant feed and reduce the ammonia nitrogen content in the water, increase oxygen, and improve water quality. Among aquatic products, submerged plants include Vallisneria, Pyracantha, etc. The phytoplankton include water peanuts and duckweed. These plants should be sown, transplanted or transplanted in winter and spring, so that the coverage rate of crab pools is over 60%. One Step SARS-CoV2(COVID-19) IgG/IgM Test IgG and lgM antibodies to 2019 Novel Coronavirus can be detected with 2-3 weeks One Step SARS-CoV2(COVID-19) IgG/IgM Test Kit NINGBO AUTRENDS INTERNATIONAL TRADE CO., LTD , https://www.metests.com
after exposure.lgG remains positive,but the antibody level drops overtime.