The quality of water quality in crab ponds is of great importance. It not only affects the growth rate and survival rate of crabs, but also affects the individual size, fullness, color of carapace, and even directly influences the breeding efficiency. In summer and autumn, the water temperature is high, which is the peak season for crabs. Ingestion and metabolism are significantly enhanced, and water quality is easily deteriorated. How to control the water quality of summer and autumn crab pools and create a good water environment is the key to promoting the normal and healthy growth of crabs. The author engaged in years of crab breeding, has accumulated a wealth of practical experience, the water quality regulation technology is summarized below for reference. I. Reasonably adjusting the water level The water level of the crab pool is generally based on the location of the platform and is controlled at about 0.8 meters. The water level around the crab ponds may be maintained at about 1.5 meters. After a long period of feeding, the water quality of the crab pool becomes old and becomes fat. It is unfavorable for the growth of crabs. Therefore, new water should be added regularly to improve the water quality of the pond. In the early summer, water is added once every 10 to 15 days, and 20% water is added each time. From June to September, water is added once a week, and 30% to 40% of water is added each time. When adding water, fresh water with high oxygen content should be added to improve the water quality of the crab pool. Water pollution and deteriorating water cannot be added. Second, control the color and transparency The color of the water in the crab pool is one of the indicators commonly used in production to identify water quality. Under normal circumstances, the color of crab ponds should be yellow-brown, light brown, and light green. The transparency should be 35-40 cm, which is beneficial to the feeding and growth of crabs. Third, increase dissolved oxygen, promote the oxidation of organic matter in the pool Dissolved oxygen is an important environmental factor that affects the life and growth of crabs. The low dissolved oxygen brings more negative effects, such as the increase of feed coefficient, the proliferation of anaerobic bacteria, and the increase of ammonia nitrogen nitrite. The main measures to increase dissolved oxygen in crab ponds are to use micropore oxygenation and sprinkling of particulate oxygen, especially from mid-July to mid-August. In hot weather, the amount of dissolved oxygen in crab ponds is relatively low. Special attention should be paid to oxygenation. The use of microporous oxygenation should be based on the situation of crab ponds and weather changes. From May to June, when the water quality and weather are not suitable, it is necessary to increase oxygen at a proper time. After June, oxygen is increased from 12:00 to 15:00 at noon on a sunny day. Oxygen is increased depending on the actual situation in the early morning, and oxygen should be turned on in advance during the rainy days. From September to October, due to the water quality of the crab pool, the weather should be hot and more oxygen should be turned on. The optimal start-up time and start-up time should be based on the weather, crab dynamics, and aerobic load. Dissolved oxygen in crab ponds should normally be kept above 5 mg/l. Fourth, increase the PH value to meet the growth needs of crab life Crab pond normal water quality standards, PH value between 7.0 to 8.5, if found low PH value, measures should be taken promptly, mainly every 10 to 15 days using 10 to 15/667 lime added water-soluble hot water pool Spill, adjust the PH value of the pool water, so that the pool water is slightly alkaline, while increasing the concentration of calcium ions in the water, supply the crab absorption, is conducive to the growth of crab shells. Fifth, sprinkling biological agents to improve water quality Sprinkling once photosynthetic bacteria, EM bacteria, and beneficial bacteria every 15 to 20 days can improve water quality and reduce ammonia, hydrogen sulfide, and nitrite content in the water, which is conducive to the healthy growth of crabs. Desly Foods Co.,Ltd. , https://www.deslygroup.com