Dissolved oxygen meter and pH meter used in fish pond culture
Dissolved oxygen meter measures dissolved oxygen (DO)
Oxygen is the life element of aquatic organisms. Long-term hypoxia slows down the growth of aquatic animals; Under severe hypoxia, fish and shrimp will float, and H2S, NH3 and NO2 in water will not be oxidized and decomposed, and the toxicity will increase. Keeping enough dissolved oxygen can decompose and transform toxic substances.
Dissolved oxygen * in water should be kept at 3mg/L, and generally at 5-8 mg/L.. Excessive dissolved oxygen will cause fish to suffer from bubble disease.
Detection method: instrument test.
Solution:
1. The normal dissolved oxygen is 5-8mg/L;
2. The dissolved oxygen in seawater is less than 3mg/L and that in fresh water is less than 4mg/L, indicating that there is no oxygen in the water, and the head may float at this time, so you should use oxygen teto or turn on the aerator to increase oxygen in time. Injecting fresh water is also a way to increase oxygen.
3. Dissolved oxygen is higher than 12mg/L, indicating that there is excessive oxygen in the water, and fish and shrimp are prone to bubble disease. The reason for the high dissolved oxygen may be that there are too many aquatic plants in the pond, the water does not flow, the photosynthesis is strong and a lot of oxygen is released. At this time, the phytoplankton can be killed by insect algae, and it is also an effective way to change water or inject new water after discharging 1/3 of the old water. For ponds where chemical fertilizers are applied, the amount of fertilizer should be controlled so as not to make phytoplankton multiply excessively.
PH meter measures pH value.
Important PH data of culture technology: prawn breeding: 8.5; Eriocheir sinensis seedling: 8.0-8.5; Freshwater culture: 6.5-9.0; Mariculture: 7.5-8.5;
When the PH value exceeds 8.5, the toxicity of ammonia in water increases and the toxicity of hydrogen sulfide decreases.
When the PH value exceeds 9.5, most aquatic animals cannot survive.
When the PH value is lower than 6, ammonia in aquatic products is non-toxic, but the toxicity of hydrogen sulfide increases. Fish and shrimp are easy to float when the PH is lower than 6.5.
When the PH value is lower than 5, it is seriously dangerous to aquatic animals.
Detection method: instrument test.
Solution:
1. Use appropriate buffer to control the normal PH value;
2. The PH value is too high: if it is higher than 9.0, measures should be taken to reduce the acid, such as adding proper amount of acetic acid;
3. The PH value is too low: if it is lower than 6, measures should be taken to increase it, and lime or water should be added to make it clean, which can be solved.
