Application of sodium humate in aquaculture.The application of sodium humate in aquaculture has the following points:

1.Reduce the toxicity of heavy metal substances and purify the aquaculture water environment.

Humic acid is a stable natural macromolecular mixed organic matter with aromatic structure. Sodium hydroxide ion exchange (acid-base reaction)It forms soluble sodium humate by ion exchange with sodium hydroxide. To be exact, sodium humate is a strong alkali and weak acid salt. Because of the reticular spatial structure of humic acid and the existence of a variety of active functional groups, sodium humate has the dual properties of physical adsorption and chemical adsorption.

(1)physical adsorption of sodium humate

The physical adsorption of sodium humate, like activated carbon, can adsorb stench and some tiny impurities with opposite electricity in water.

(2)Chemical adsorption for sodium humate

Chemical adsorption for sodium humate is a kind of reaction between radical anion and metal cation. Such as sodium humate  is present in the form of humic acid ions and sodium ions in water. When the divalent and trivalent cations such as aluminum ions or lead ions are present in the water.  The humic acid can be re-complexed with the high-valent cation to form a complex-state humic acid salt which is insoluble in water. Thereby reducing the heavy metal ions in the water. The adsorption of the humic acid can effectively improve the environment of the water and reduce the heavy metal ions.

humic acid molecule can carry on micro redox reaction.

In addition, Humic acid molecule itself has oxidation group and reduction group. So humic acid molecule or molecule itself will carry on micro redox reaction. In the process of reaction, there will be the participation of free radical and release ecological oxygen. Which can inhibit some bacteria and improve the beneficial environment of water. The animal husbandry and water production bureau in Haidian District of Beijing soak the 2000 injured fish for 30 minutes with the concentration of 0.1% to 0.3% of the humic acid solution. The wound is healed after 7 to 10 days.  All the fish survived.  While 2000 injured fish without humic acid recovered slowly and 150 fish died in a week. 

2.Improve sediment, detoxification and deodorization, improve feed utilization rate:

Application of sodium humate in aquaculture.(1)Sodium humate belongs to reticular and porous structure. Which can improve sludge viscosity. Make the sediment loose.  Change the permeability of sediment. Improve the activity of aerobic microorganisms. And provide rich feed for fish and shrimp.
(2)Sodium humate can adsorb part of NH3 and H2S in the bottom environment. Thus removing the stench of sediment and thus reducing the pollution to the environment. According to Wang Neigui research., sodium humate can absorb part of ammonia. Thus reducing its harm to intestinal and external environment. From this point of view, we can consider whether some sodium humate can be added to reduce the deterioration of the environment by adding a part of sodium humate when the compound feed is widely used in the later stage of aquaculture animals. Humic acid is associated with feed to form macromolecules in intestinal tract.  Which increases the flow time of feed in intestinal tract and improves the absorption and utilization efficiency of feed.

3.Physical shading:

After the application of sodium humate, it will dissolve quickly and form soy sauce color water. The larger quantity the use of sodium humate, the darker the color. The darker the color can prevent part of the sun from reaching the bottom of the water. So that it can play the role of preventing moss. And the use is relatively large in crab culture ponds. In practical use, the time of keeping soy sauce color of sodium humate in leonardite is shorter, generally in 1 – 3 days. And the time of keeping soy sauce color of sodium humate in lignite is longer, generally more than 5 days.  The longest has seen 14 days of continuous soy sauce color. Therefore, it is suggested that sodium lignite humate should be applied in physical shading.  But because the color of lignite humic acid is lighter than that of leonardite humic acid, the amount of humic acid in lignite can be increased as appropriate.

4.Algae preservation:

In the Crab Pond, it is of great concern to the Algae preservation. Sodium humate can improve the root development of algae. It is recommended to use 500-1000g per mu. From the practical application point of view, it is recommended to directly spray the granular sodium humate product after planting water grass in the crab pond.  So that the sodium humate can reach the bottom rapidly.  Thus promote the root growth.
At present, humic acid of lignite is mainly distributed in Huolin River, Hulunbeir, Heilongjiang Tahe, Heihe, Hegang, Qitaihe and other areas, Zhaotong, Yunnan. Leonardite is mainly distributed in Inner Mongolia Wuhai, Shanxi, Xinjiang and other places. The products are mainly powder, granular and flake.
The diversification of products and the quantification of manufacturers have created the quality disorder of the current products. I hope that when purchasing, we will pay more attention to the price and quality of the products. And adjust the use of the products according to the products of different regions.