(1) The characteristics of light green and turquoise water color and its regulation technology 1. Characteristics This water color is the best water color that can be obtained in fish, shrimp and crab culture, especially in larval culture. This water color is rich in Chlorella, scenedesmus, Platycladus orientalis and other algae in Chrysophyta and Chlorophyta. These algae are rich in nutrients and vitamins, which are easily digested and absorbed as nutrients; At the same time, through photosynthesis, dissolved oxygen can be provided to water. The transparency of this watery water body is mostly 20 ~ 30cm, the water quality is stable, and there are few organic and inorganic suspended substances in the water. The "fat and cool" water quality needed by aquaculture is this sparse water quality, which is a high-quality water color to ensure good aquaculture benefits. 2. To cultivate and maintain this water color control technology (1). Before stocking, disinfect the pond mouth with quicklime and put in organic fertilizer. Generally, the dosage of lime per mu is about 150 kg. After cleaning the pond, organic fertilizer is put into the pond to cultivate the water quality, depending on the fertility of the sediment in the pond mouth, and the dosage is100 ~150kg/mu. (2) When the water color changes from light green to dark green in the breeding process, fresh water can be appropriately added for dilution and adjustment. To keep this water color for a long time. (2) The characteristics and control technology of dark brown and yellow-green water color 1. Characteristics In these two water colors, diatoms are the dominant species of phytoplankton, and some green algae such as neophyta, navicular, Phaeodactylum and dinoflagellate are the main species. The pigments in these algae are brown or yellowish brown. This water color is the best water color in fish, shrimp and crab culture. This water-colored algae is easily digested and absorbed by fish, and it is rich in nutrients, rich in inorganic salts such as calcium, magnesium and iron, and various vitamins. The water is rich in dissolved oxygen and scarce in toxic and harmful substances, which is suitable for the growth and development of fish and has low incidence. This water color is the best water quality in the seedling stage. However, the disadvantage of this water color is its short duration, and it is easy to change into other water colors after 10 ~ 15 days. 2. Control technology for breeding and maintaining brown, yellow, green and water color ① Fresh water should be replenished in time, and it should be replenished every 2-3 days in the peak period of breeding, and the amount of water injected each time is about L/ 10 of the total aquaculture water. (2) timely topdressing, which can use decomposed organic fertilizer and fertilizer containing phosphorus, magnesium and calcium, such as calcium hydrogen phosphate. Because it supplements the nutrients needed by diatoms and promotes the growth and development of diatoms, the water color can last forever. (3) Characteristics and control technology of strong green water color 1. Features This kind of water is dark green in color and its concentration increases, so its transparency is low, generally less than 15 cm. The algae in the water are mainly Chlorophyta, such as Spirulina and Chlamydomonas. This kind of water is rich and stable, which can last for a long time, and climate change has little effect on it. Most of the pond water bodies in the peak period of aquaculture are of this water color. In strong green water, algae are aging day by day, but with strong photosynthesis and good oxygen production function, they can still be digested and absorbed, so they are still among the good water quality in adult fish culture. However, in the high temperature season of aquaculture, attention should be paid to supplementing fresh water to adjust the water quality, so as to prevent the water quality from further thickening due to the increase of residual bait and excrement, which will lead to the increase of the concentration of harmful substances such as ammonia nitrogen and nitrite at the bottom of the water body, the decrease of dissolved oxygen in the water and the deterioration of the water quality, thus reducing the aquaculture effect and even causing diseases and losses. 2. technical measures to control and adjust the color of strong green water ① add fresh water every day to reduce the color concentration of water, and the amount of water added is 5% ~ 10% of the total water body. ② Reduce the feeding amount appropriately. ③ Sprinkle zeolite powder or quicklime to adjust water color, and the dosage is 0. 1 kg/m3. 2. Types, characteristics and control technology of inferior water color (I) Characteristics and control technology of blue-green water color 1. Characteristics Due to the proliferation of cyanophyta (mainly caused by Microcystis), the color of this water is turbid and viscous. There are a large number of blue-green suspended particles in the downwind water of Tangkou, and there are banded and cloud-like blue-green algae groups on the water surface to form oil films and bubbles (also known as when the water temperature reaches above 28℃, algae will die one after another, producing toxins and destroying water quality). In the high temperature season from July to August, most water bodies with excessive aquaculture density will produce this water color. If the blue-green water quality lasts too long and the concentration is too high, it will do great harm to aquaculture, easily lead to fish diseases, cause a large number of deaths and bring huge losses to aquaculture production. 2. Elimination of technical measures to control the water quality of blue-green water (1) Discharge method: discharge surface water through the opening above the water outlet of aquaculture water body, and discharge blue-green algae out of the pond mouth for 2-3 days continuously. Or use artificial dense nets to fish downwind. (2) Use 0. 1g/m chlorine dioxide. Adding zeolite powder 10g/m3 and spraying it in the whole pond for 1 ~ 3 days can effectively eliminate cyanobacteria and improve water quality. (3) After the blue-green water fades, calcium hydrogen phosphate is applied and re-cultured into green algae water or diatom water. (2) The characteristics and control technology of dark brown water color 1. Features The color of this water is also called soy sauce color water, which is dark brown or dark reddish brown and dark yellow brown. The main reason for this water color is that after feeding, the residual bait and excrement are too much, and the organic matter decays and decomposes at the bottom of the pond, forming eutrophic water quality, which increases the suspended organic matter in the water, worsens the water quality and increases the accumulation of poisons.
Characteristics and control technology of clear water color 1. There are two characteristics of this water color: one is moss water, that is, the bottom of the water body is covered with moss, which makes the water body clear and thin, and the water body lacks nutrition, which makes the beneficial algae extinct, and it is difficult for the cultured larvae to survive after entering the moss; Second, it is black and clear water, which is transparent to the end, but it is black and clear and has a fishy smell. The extinction of phytoplankton in the water and the emergence of a large number of large zooplankton are culturally called "turning to water". The latter kind of water is bad water with deteriorating water quality, which is not suitable for aquaculture.