You may not know all these common knowledge about dissolved oxygen, the aerator parts manufacturers tell you!

The main sources of dissolved oxygen in ponds are generated by photosynthesis of phytoplankton, mechanical aeration, and the dissolution of oxygen from the air into water. The consumption of dissolved oxygen is mainly caused by the respiration of plankton and the decomposition of organic matter in the water. In addition, dissolved oxygen in the pond is also affected by many factors such as light, wind, air pressure, plankton, and water quality. Although there are certain rules of change, it is impossible to accurately determine the dissolved oxygen content in the pond based on experience alone. Misjudging will have a high risk!

First, the change of dissolved oxygen at the bottom is an important indicator to reflect the health of fish and shrimp, and it can make a scientific reference for the management of substrate and water quality.

Use the oxygen measuring instrument to grasp the change rule of dissolved oxygen in the water. Dissolved oxygen records should be made four times a day: once at 05:30 in the morning, the lower stage of dissolved oxygen in the day; twice at 08:30 in the morning, which can be used as a starting feed The basis is three times at 15:30 in the afternoon and the higher stage of dissolved oxygen in a day; the fourth time is at 23:00 at night, which can be used as the basis for whether to turn on the aerator. Through long-term observation and recording, changes in substrate and water quality can be predicted and adjusted in advance.

1. The change of dissolved oxygen at the bottom should not exceed 7mg / L within a day. This is an important indicator of fish and shrimp health. The substrate and water quality are good and suitable for fish and shrimp growth.

Special attention should be paid: in the early stages of aquaculture, if harmful algae is produced due to imbalance of algae, fish and shrimp may also develop disease although the dissolved oxygen at the bottom changes normally. Therefore, in the early stage of cultivation, microbial preparations for removing organic matter at the bottom of the pond and cultivating beneficial algae phases should be regularly put on; in the middle and late stages of cultivation, microbial preparations for removing organic matter at the bottom of the pond and degrading nitrite and ammonia nitrogen should be regularly put in order to reduce the organic matter-induced Hypoxia, cultivate beneficial bacteria and algae phase; regularly add powder burned from shells to increase the total alkalinity of aquaculture water. The suitable total alkalinity for shrimp farming is 100-200, more than 300 or less than 60. Not easy to raise. Stable pH, suitable pH value for breeding is 7.8-8.6.

2. The dissolved oxygen at the bottom changes within 8-9mg / L within a day, indicating that the culture environment of this pond is in a sub-healthy state, the water quality is partial fertilizer, the algae tends to be rich, and the bottom substance changes to a bad direction. The bottom of the pond begins to breed a lot of harmful bacteria, Ammonia nitrogen, nitrite and hydrogen sulfide cause slow growth of fish and shrimp.

Treatment methods of aerator parts manufacturers: A. Reduce feed and mix with microbial preparations to enhance the fitness of fish and shrimp; B. Appropriately kill some over-proliferated algae (such as spraying more than 6:00 am in the morning) Bottom: Bottom aeration, disinfection (such as splashing hydrogen peroxide or dry spraying aerators at more than 11:00 in the evening), applying a microbial preparation at noon on the third day, cultivating beneficial bacterial phases, and cultivating the habit of using microbial preparations on a regular basis; D. placing shells Powder to increase the total alkalinity of the water body and stabilize the water body.

3. The change of dissolved oxygen at the bottom exceeds 10mg / L within one day, indicating that the fish and shrimp breeding environment is in an unhealthy state, the substrate is severely blackened, the water quality is severely fertile, the algae is too rich, and the shrimp crusts are softened or even stagnated, which can easily cause stealing. Or other diseases.

Scientific feeding of dissolved oxygen at the bottom

The most suitable range of dissolved oxygen at the bottom is 5-8mg / L, and it is a hypoxia state between 2.5-4.5mg / L. It cannot be in this state for a long time. In addition to turning on the aerator in special weather, the bottom needs to be aerated. . Most fish and shrimp start to float at 1.5mg / L (crab is 2.5mg / L), shrimp at 0.5mg / L (grouper, salmon, trout, sea bass 0.8 mg / L, eel 0.6 mg / L, crab 1.5 mg / L) began to suffocate. The bottom dissolved oxygen should be higher than 5mg / L during one feeding, and the last feeding should be higher than 5.5mg / L. This can not only improve digestion and absorption, reduce feed costs, but also reduce pond bottom pollution and reduce the incidence of disease.

Third, the effective use of dissolved oxygen at the bottom of the aerator

The saturation degree of dissolved oxygen in water is affected by temperature and salinity. At a certain temperature, pure fresh water can only reach the saturation value no matter how the oxygen is increased, which is a natural law. When the saturated dissolved oxygen value is exceeded, the oxygen increasing effect of the aerator is not obvious, not only wasting electricity costs, but also easily causing fish and shrimp bubble disease. The algae stopped photosynthesis at night, and the supersaturated dissolved oxygen produced by photosynthesis would overflow the water surface during the day. At this time, turning on the aerator will only accelerate the overflow of supersaturated dissolved oxygen. The more the aerator is turned on, the faster the dissolved oxygen will drop. . At 13: 30-15: 30 on a sunny day, open the aerator to stir the water body, so that the upper and lower water bodies communicate, increase the dissolved oxygen at the bottom, promote the material circulation in the pool, and improve the water quality and bottom condition of the pond.

Fourth, the calculation method of dissolved oxygen value in salty water

At 30 ° C, the saturated dissolved oxygen in fresh water is 7.6 mg / L. In water with a salinity of 10 ‰, the saturated dissolved oxygen at this time is 7.6-10 × 0.036 = 7.24mg / L.