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Official account
First, the treatment of moss
Moss is a filamentous algae that is a collective term for several filamentous algae such as sponge, double star algae and transpose algae.
When the temperature rises above 10 °C in the spring, the moss begins to multiply and grow.
In the early days, it is attached to the bottom of shallow water like hair, and as the temperature rises, it multiplies in large quantities, growing into wisps of green filament standing upright in the water; in severe cases, it will cover the entire pond like a huge net.
1. The harm of moss
When the moss breeds in large quantities, it will absorb a large amount of nutrients in the water body, making the water body thin, and when the crab species climb into the moss, it will also entangle the crab species and seriously affect the normal feeding and activity of the river crab.
When moss is capped or adsorbed on aquatic weeds, it will hinder the photosynthesis of aquatic weeds, causing aquatic weeds to shrink and die, which in turn affects water quality.
When it dies in large quantities, it decomposes and releases a large number of toxins, causing the water quality to turn black and smelly, the ammonia nitrogen content exceeds the standard, and the dissolved oxygen content in the water body is low, causing harm to the river crab.
2. The main cause of moss production
(1) The pond is not complete.
If there has been a serious moss problem in the previous year, the crab pond has accumulated water in winter, it has not been drained in the spring of the following year, and the pond has not been cleared or dried before raising crabs, the incidence of moss in such crab ponds is extremely high, and the degree of harm is also greater.
(2) The pool water is too thin.
Before stocking, the culture pond was not fertilized or insufficiently fertilized, resulting in excessive thin water and causing moss to grow.
(3) The early stage of fertilizer water is not fertilized or the stage of aquatic grass growth is not timely fertilization, and after the aquatic grass consumes the nutrients in the pond, the beneficial algae cannot get nutrients.
Therefore, after planting grass, we must pay close attention to the changes in the water color in the pond, once it is found that the aquatic grass grows rapidly and the transparency of the water body is improved, it should be timely fertilizer to maintain the transparency at 30 cm.
(4) The one-time amount of snails is too large, resulting in thin water quality, difficulty in fertilizer and moss breeding. Snails are generally stocked before and after the Qingming Dynasty, and the fertility of the water quality must be paid attention to before stocking snails.
It is best to fertilize the snails in large quantities before stocking them.
(5) Excessive application of phosphate fertilizer and application of unfermented organic fertilizer, so that the water ecology is damaged, or when transplanting aquatic weeds and snails, the moss is brought into the crab pond, resulting in moss flooding.
3. Measures to prevent and control moss
(1) Thoroughly clear the pond
Remove too much pond bottom silt, the thickness of the pond bottom silt does not exceed 15 cm, and then dry the pond for more than 20 days.
When clearing the pond, 1.5 kg of copper sulfate per mu is dissolved in water and poured into the bottom of the pond and the slope of the pond, and after 5 days, about 10 cm of water is injected into the pond, and the whole pool is evenly sprinkled with quicklime of more than 150 kg per mu.
It should be noted that when the whole pool of quicklime is sprinkled evenly, such as when there are too many pieces of ash in one place and cannot be dissolved, it should be rakeed with an iron rake.
Crab ponds treated by this method, as long as they are properly managed, generally rarely have moss.
(2) Moderate fertilizer water
The growth of moss requires sunlight, and moss lives at the bottom of the water, and can increase the fertility of the water through fertilizer water, reduce transparency, and weaken light.
Due to the low water temperature in the early stage, algae are not easy to grow, and the water is not easy to fertilize.
First of all, after clearing the pond, the base fertilizer should be applied at the bottom of the pond, generally 100 to 150 kg/mu of organic fertilizer.
Then according to the water quality of the application of inorganic fertilizer, the amount of fertilizer in principle depends on the bottom of the pond, the water quality of the inlet water, generally in March to May to maintain the transparency of the pond water quality in 30 ~ 35 cm, the transparency is too high, indicating that the pond water is thin, need to increase the amount and frequency of fertilization.
After entering June, the transparency of the aquaculture pond water should be controlled at 40 to 45 cm.
Therefore, the principle of controlling the transparency of pool water: the water temperature is low, the transparency is also low; the water temperature is high, and the transparency should be controlled a little larger.
The organic fertilizer must be fully decomposed and fermented, and the inorganic fertilizer applied is mainly compound fertilizer.
When fertilizing, it should be noted that if the moss has occurred in large quantities, it is not possible to fertilize a large amount of fertilizer, because there is more nutrition after fertilization, which accelerates the growth of moss.
That is, the more fertilizer is applied, the more the moss grows.
(1) The reason for the poor effect of fertilizer water
The water temperature is low; the light is insufficient; the dissolved oxygen of the water body is too low; the water body is too little; there are too few water body algae; there are too many zooplankton in the water body; there are more residues of water drugs; the pH value of the water body is too high or too low; the water body wind and waves are too large, and the up and down convection is more serious; the fertilizer and aquatic products used are not dissolved in the water or the solubility is poor.
(2) Fertilization measures
In view of the above situation, it is recommended that farmers take the following countermeasures to obtain a more satisfactory fertilizer and water effect.
a. When the water temperature is low and the light is insufficient:
Use amino acid fertilizer water paste + low temperature spores or photosynthetic bacteria to soak the whole pool, with oxygenators or start aerators to use;
When using solid fertilizer, it should be fully dissolved and then used, generally soaked for more than 6 hours, if more fertilizer sediment is found, it proves that the fertilizer water product quality is poor, and the product with better fertilizer water product quality can be used to ensure the fertilizer water effect.
b. When the dissolved oxygen of the water body is too low and there are many zooplankton:
First use insecticides to kill too many zooplankton (in the process of killing zooplankton, special attention should be paid to the selection of insecticides in polyculture ponds to ensure that there is no adverse effect on polyculture shrimp and crabs), and then use potassium persulfate with aerator tablets to sprinkle the whole pond in the morning, after an interval of 2 to 3 hours, use amino acid fertilizer ointment + phosphate fertilizer + em bacteria to soak the whole pond (the use of sunny days is better).
c. When the water body uses a large number of drugs, turbidity:
First use the fruit acid organic acid (5 to 7 acres / bottle) after the whole pool is sprinkled, and then use potassium persulfate whole pool to sprinkle, the next sunny morning using amino acid fertilizer water paste + algae + EM bacteria soaked in the whole pool sprinkled.
(3) Stocking of fine-scaled oblique-jawed catfish
Before the end of March, 100 to 200 species of slender-scaled oblique-jawed catfish with a size of 6 to 8 cm are stocked per mu.
The feeding of aquatic algae by the fine-scaled oblique-jawed catfish can effectively control the amount of moss in the water body and prevent the deterioration of water quality due to moss outbreaks;
The carp can also eat the residual bait of the river crab, which can effectively prevent the impact of food spoilage on water quality due to the spoilage of the bait.
(4) Drug treatment
If the moss has already occurred in large quantities, it is necessary to treat the moss by means of drug killing. Mix with wet fine soil and the moss-killing herb spirit and sprinkle it dryly on the dense moss, and the effect will be seen after 2 days of use.
In the area where the moss is concentrated, the copper sulfate and ferrous sulfate compound are directly sprinkled on the moss 5:2 for killing, and the quicklime is thrown once after 3 to 5 days.
When using drugs to kill moss, it should be not used in the moss stage of river crabs.
Second, the water bloom
"Blooms" are a natural phenomenon in freshwater caused by outbreaks of cyanobacterial blooms. With the arrival of the high temperature season, cyanobacteria will continue to appear, and the treatment of cyanobacteria has always been a problem in the process of river crab farming.
1. The main cause of "water bloom"
(1) High temperature
At room temperature, cyanobacteria do not grow faster than other common algae, and the growth rate of cyanobacteria accelerates with the increase of water temperature.
Under certain temperature conditions, cyanobacteria grow faster than other algae; in the high temperature season, the growth advantage of cyanobacteria will be reflected.
(2) Eutrophication of water bodies
Eutrophication of water bodies is caused by the following reasons:
With the progress of breeding, aquatic animals continue to grow, the amount of feed input will increase, the accumulation of residual bait, the increase of excrement of farmed animals, etc., resulting in nutrients exceeding the self-purification capacity of water bodies;
The accumulation rate of a large amount of feces and residual bait is far greater than the degradation capacity of microorganisms.
(3) The ratio of nitrogen and phosphorus is out of balance
The imbalance of beneficial algae nutrient sources leads to a slowdown in the reproduction rate of algae, a decrease in the amount of beneficial algae, and the amount of nutrients obtained by algae in the water is also reduced, and the decomposed nutrients cannot be fully utilized by the algae, and after accumulating too much, there is a feedback inhibition effect, resulting in the obstruction of the material cycle.
(4) Human influence
Frequent use of pesticides and disinfectants in the breeding process, and then not timely replenishment of beneficial bacteria, resulting in the lack of beneficial microorganisms in the water body, so that the degradation capacity of the water body is greatly reduced.
2. Occurrence of cyanobacteria in ponds
(1) There is no aquatic weed in the pond or the amount of aquatic weed is very small, and the nutrients cannot be fully utilized, resulting in too high organic matter content in the later breeding pond.
(2) The amount of snail stocking is too small, or the survival rate of snails in stocking is not high, resulting in rich organic matter content at the bottom of the pond in the later stage.
(3) The use of chemical fertilizers and organic fertilizers in the early stage is too much, and the use of microorganisms or the bottom change is small in the later stage, and the decomposition of organic matter is limited, resulting in the accumulation of fertilizer in the pond.
In the later stages of breeding, the temperature rises, the pH increases, the water body forms eutrophication, and cyanobacteria begin to occur.
3. Prevent the occurrence of cyanobacteria
(1) Frequent water change to ensure the normal growth of aquatic weeds, so that aquatic weeds account for about 50% of the pond area. In the middle of breeding, it is necessary to pay attention to the timely topdressing of aquatic plants and maintain the transparency of the water body at 30 to 40 cm.
(2) In the early stage, if the amount of snail stocking is not enough, a batch of snails can be added in June, generally the total stocking amount is 250 ~ 300 kg / mu, and the quality of the snails should be guaranteed.
(3) In the early stage of river crab breeding, try to use biological fertilizer to reduce the amount of chemical fertilizer used, and organic fertilizer should be fermented through Bacillus and yeast;
In the middle stage (after May), microbial agents should be used regularly in the pond, and the fertilizer water in the later period is mainly based on amino acid fertilizers, and the original powder of Bacillus subtilis and denitrification bacteria are used 1 to 2 times a month to decompose the organic matter at the bottom of the pond.
4. The harm of cyanobacteria
(1) When cyanobacteria multiply in large quantities, on the one hand, it inhibits the growth and reproduction of beneficial plankton in the farmed water body, and hinders the photosynthesis of other algae;
On the other hand, it also blocks the gas in the air from entering the aquaculture water body, resulting in a serious shortage of dissolved oxygen in the aquaculture water body, hypoxia or hypoxia, causing river crabs and other aquaculture animals to fall ill or even die.
(2) A large number of cyanobacteria will also corrupt the water quality, and produce a large number of harmful substances such as algal toxins, hydroxylamine and hydrogen sulfide, which directly endanger the health of river crabs and other aquaculture animals.
5. Reduce the amount of cyanobacteria in the pond
Cyanobacteria occur during pond culture and it is difficult to completely remove cyanobacteria, but the following measures can be taken to reduce the amount of cyanobacteria in the pond.
(1) In a small pond, the cyanobacteria can be enclosed in a small corner with a bamboo pole or plastic pipe in the windy area under the pool in windy weather, and then the cyanobacteria can be removed with a dense net.
(2) Reduce the pH of the pool water, and the pH value of the pool water can be reduced to 7 to 7.5 by organic acids. PH reduction should be gradual to prevent harm to river crabs and other aquaculture animals.
(3) In the downwind of the pond on a sunny day, the appropriate amount of copper sulfate, ferrous sulfate mixture or complexed copper preparation is directly sprinkled on the cyanobacterial algae mass at the edge of the pool, which can effectively kill part of the cyanobacteria
(Note: The area of drug spilling should not exceed 1/4 of the pond area, and the pond should pay attention to oxygenation on the day of spilling, and pay close attention to the water quality in the pond and the situation of river crabs, especially at night, to patrol the pond regularly).
(4) If a large number of cyanobacteria erupt, the water can be changed once a day if conditions permit, the cyanobacteria in the downwind outlet is eliminated, and then killed.
Cyanobacteria will produce cyanobacterial toxins after death, first detoxification, you can first change 1/3 of the water, and then use a detoxifier to remove heavy metals and cyanobacterial toxins, while using immunogly polysaccharides and detoxification high stability vitamin C mixing bait feeding, in order to enhance the physique of river crabs, reduce stress response.
One detoxification may not be complete, but can be used 2 to 3 times in a row.
After detoxification, the bottom can be changed 1 to 2 times continuously, and the bottom can be changed at the same time with the oxygenation effect is better. After the water quality is stable, the beneficial algae are re-cultivated in fertilizer water.
(5) Stocking some silver carp and snails can reduce the eutrophication of water bodies, thereby controlling the reproduction of cyanobacteria, and can also stock some tilapia, and tilapia can directly feed on cyanobacteria.
(6) After rain, a certain amount of water quality improvers are applied to the water body, and a certain amount of biological compound fertilizer (500 grams/mu) is supplemented, which can restore the reproduction and growth of beneficial algae in the water body in a short period of time and inhibit the reproduction of cyanobacteria (note that oxygen should be carried out 3 hours before the water quality improver is spilled).
(7) Transplant a certain amount of aquatic higher plants such as hyacinth, manjiang red, and water peanut in the cultured water body, and control the nitrogen and phosphorus content in the water body through higher aquatic plants to inhibit the large reproduction of cyanobacteria.
(8) When adding water or replacing new water, pay attention to the water quality of the outer river, such as when there is more moss in the water source, it should be avoided to bring cyanobacteria with the added water.
The above methods are difficult to completely kill or control cyanobacteria with a single use, and should be modified by drug killing, biological agent water transfer and substrate improver to improve water quality and substrate.
Through comprehensive control measures, the control and treatment of cyanobacteria in crab ponds can achieve better results.
Third, the water body is turbid
Turbidity in pond water is a common problem in river crab farming, and short-term turbidity has little impact on production.
However, long-term turbidity directly affects the photosynthesis of algae and aquatic weeds, resulting in insufficient dissolved oxygen in the water body, making harmful substances such as ammonia nitrogen, hydrogen sulfide, nitrite and other harmful substances in the water body exceed the standard, and the growth and germination of aquatic grasses is easy to fall and die without light, and the water quality of the pond is corrupted after decay, thus affecting the normal molting growth of river crabs.
1. Common causes of turbidity in the water body of crab ponds
(1) The amount of feeding is not enough, caused by the feeding activity of river crabs.
(2) Parasite parasitism makes the river crab restless and crawling around.
(3) Zooplankton rotifers are more caused.
(4) There are many small miscellaneous fish.
(5) The dissolved oxygen at the bottom of the pool is insufficient, and the river crab is restless.
(6) Insufficient or anhydrous weeds, poor self-purification ability of water bodies.
2. Measures to be taken to deal with turbidity in water bodies
(1) If the amount of feeding is insufficient, it is necessary to gradually increase the amount of feeding, and it is advisable to have a slight surplus the next day.
(2) Check the gills and body surface of the river crab, if there is ciliate parasitism, you can sprinkle the whole pool with fibrella net and other drugs, and when a large number of parasitisms are parasitized, it is splashed twice.
(3) If the water color is white, there are fewer phytoplankton in the water body, and there are more zooplankton, it is necessary to kill insects first (using avermectin, etc.), and then fertilize the water (using amino acid fertilizer water paste, etc.).
(4) If it is turbidity caused by wild trash fish, it can be removed by adding "Qingtang 2008" to the feed.
(5) Ponds with insufficient or no aquatic weeds can transplant disinfected water peanuts into the pond.
Fourth, water eutrophication
Due to the increase of nutrient salts in aquaculture water bodies, the productivity of algae and aquatic plants has increased, and the water quality has declined, resulting in eutrophication of water bodies.
1. The harm of eutrophication of water bodies
(1) Outbreaks of harmful algae
Due to the accumulation of feces and residual bait in the water body, the ability of microbial degradation and transformation is weakened, many substances exist in the form of macromolecular organic matter, and small algae cannot be absorbed and utilized, but harmful algae such as naked algae, dinoflagellates, cyanobacteria and other harmful algae can be absorbed and utilized, and this environment provides conditions for rapid reproduction of harmful and bad algae.
(2) Affect the sensory traits of the water body In the eutrophication of the water body, cyanobacteria and other large multiplication, the color of the water body increases, the water quality is turbid, the transparency is reduced, and the smell is emitted.
(3) Produce harmful substances Many algae in eutrophicationic water bodies can secrete and release toxic and harmful substances, so that the quality of water declines.
(4) Affect the ecological environment of water bodies In eutrophication-polluted water bodies, the nitrogen source of the water body accumulates too much, and the microbial transformation capacity is not enough, which leads to the accumulation of organic matter, anaerobic decomposition and toxicity.
Most harmful microorganisms are anaerobic bacteria, if the water body for a long time dissolved oxygen is insufficient, anaerobic bacteria will rapidly multiply in large quantities, and a large number of toxic and harmful substances such as ammonia nitrogen, nitrite, hydrogen sulfide and other toxic and harmful substances are deposited.
Eutrophication of water bodies leads to the lack of oxygen in water bodies, the lack of beneficial plankton, the increase of toxic and harmful substances, the stability and diversity of aquatic organisms are reduced, if it is rainy weather, the temperature of water bodies, pH, etc. change rapidly, and the water body will undergo great changes - inverted algae, resulting in intensification of the stress response of farmed organisms, resulting in disease outbreaks, causing a large number of deaths of fish and other aquatic organisms.
In addition, it also affects the utilization of biological resources such as fisheries, reducing the economic value of water bodies.
2. Commonly used detection methods
In production, a relatively simple instrument can be used to directly determine the degree of eutrophication of water bodies on site or through visual inspection.
(1) Transparency measurement method
A white porcelain dish with a diameter of 30 cm (iron plates or other materials can also be painted white instead) is placed in the water and the depth when visually visible is used as transparency.
Therefore, the measurement time should be determined at 9 to 16 o'clock every day.
Transparency can roughly reflect the degree of eutrophication of water bodies, and the smaller the transparency, the higher the degree of eutrophication of water bodies.
Sometimes, although the degree of eutrophication of water bodies is high, the measured transparency is still large, because: large filamentous fungi and aquatic plants multiply in large quantities, phytoplanktonic algae outbreaks of death, rainy days of phytoplankton algae sinking, water body by heavy metal pollution is not conducive to algae growth.
(2) Visual inspection
Through the naked eye to observe the color of the water, judge the quality of the water and the degree of eutrophication.
Water color is the color of the total composition of plankton (including phytoplankton and zooplankton), organic matter and suspended solids mainly in the pond water.
Identifying pond water color and timely regulation is an important technique in aquaculture.
(3) Typical poor water quality
(1) Green water body: the nitrogen content in water is large.
(2) Black brown or soy sauce color water: there are many leftover baits and residual baits, the substrate deteriorates, and the water body is dominated by flagellar, naked algae, brown algae, etc., and farmed animals are prone to disease.
(3) Yellow water: a large amount of organic matter accumulated in the pool is decomposed by bacteria, and this color is easy to occur when the pH value of the pool water drops, which is not conducive to the growth of farmed animals.
(4) White turbid water: mainly contains ciliates, rotifers, copepod zooplankton, clay particles or organic debris.
(5) Clarified color water: poor nutrient water or water contaminated with heavy metals, which is not conducive to aquaculture.
3. Recommended measures to reduce its harm
(1) Photosynthetic bacteria (3 billion / ml) and nitrifying bacteria (3 billion / g), a one-time amount, 3 to 4 ml and 2 to 3 grams per cubic meter of water, respectively, the whole pool is sprinkled, used once in 15 days, and used 2 to 4 times.
(2) Bacillus high potency (5 billion / g) and lactic acid bacteria (3 billion / g), a one-time amount, 0.3 to 0.4 grams and 3 to 4 ml per cubic meter of water, respectively, sprinkled in the whole pool, used once in 10 to 15 days, and used 2 to 4 times. After the application of microecological preparations, attention should be paid to oxygenation.
(3) According to different conditions of eutrophication water bodies, silver carp and bighead carp can be stocked according to 50 to 80 grams per cubic meter of water body, and the proportion is flexibly mastered.
(4) Frequently add new water, add water once in 10 to 15 days, and add about 20 cm at a time.
(5) Make good use of the aerator (in addition to the lack of oxygen in the water body, the fish floating head focus on the start, every sunny day at noon, afternoon start 2 to 3 hours), oxygenate the water body, agitate the water body and plant aquatic weeds in the pond.
Fifth, the hydrogen sulfide in the water body is high
Hydrogen sulfide is a highly toxic soluble gas that has a serious toxic effect on organisms.
In the iron salt is insufficient, dissolved oxygen is too low, especially when the water level and pH value drop, the H2S content is very easy to be too high.
The source of hydrogen sulfide in water bodies is mainly produced by the decomposition of anaerobic microorganisms such as feed residue bait, carcasses of aquatic organisms and silt in the absence of dissolved oxygen.
When the content of hydrogen sulfide in water bodies is high, the main prevention and control measures are as follows.
(1) Organic acid detoxification, one amount, 0.75 to 1.0 grams per cubic meter of water, sprinkle the whole pool, once a day, for 2 days.
(2) Bacillus with aerobic tablets, a single amount, 333 to 400 grams and 167 grams per acre of water body, respectively, the whole pool is spilled.
(3) Promote the vertical circulation and mixing of water, break the hierarchical stagnation state, avoid sediment, especially to avoid the development of the bottom water into a reduced state.
It can be used to increase the dissolved oxygen in the pool, generally using mechanical oxygenation or chemical oxygenation, to promote the oxidation of hydride sulfide into sulfate.
(4) As far as possible, keep the substrate, the bottom water is neutral, slightly alkaline (pH 7.5 ~ 8.5), for which lime can be applied, try to avoid the bottom, the bottom water is acidic.
(5) The application of iron agent, improve the content of Fe2+ and Fe3+ in the bottom water of the substrate and bottom layer, once there is sulfide formation, it can be converted into FeS, and the elemental sulfur is fixed in the sediment, so as not to accumulate in the water and cause harm.
(6) Avoid a large amount of sulfate entering the aquaculture water body.
Sixth, the water body is white in color
1. The cause of the whitish water color of the pond water body
(1) In the early stage of breeding, it is usually caused by too many zooplankton or sudden mass death of phytoplankton, and single-celled algae cannot grow normally.
(2) In the later stage of breeding, due to sudden weather changes, dissolved oxygen deficiency, increased toxins, feeding and feeding, improper disinfection and treatment, etc., it can also cause abnormal mass deaths of single-celled algae, and then harmful microorganisms multiply or zooplankton reproduction excess.
2. The main prevention and control measures for the whitishing of water bodies
(1) Open more aerators, and then drain part of the bottom water and introduce some new water.
(2) Use ammonia repellents, oxygenators, photosynthetic bacteria.
(3) Introduce new algae species and appropriate fertilizer.
(4) If the content of ammonia nitrogen or nitrite is too high in whitish water, it should first use an ammonia water purifier (such as zeolite powder, aluminum chloride), and reduce or stop feeding feed.
After most of the zooplankton have been ingested or died, some new water is introduced and fertilized.
(5) For the whitishing of water caused by rotifers, etc., it can be continuously oxygenated first, and the insecticide is sprinkled along the pond in the early morning of the next day and phosphate fertilizer is increased in the morning.
(6) Sprinkle vitamin C, etc., to reduce the stress response of aquatic animals.
Seven, the water color of the water body is thin
Only by maintaining a certain degree of fertility can the water body maintain a good material circulation and energy flow in the water body. For thin aquaculture water bodies, the measures often taken are fertilization, but attention should be paid to the method of fertilization.
(1) In pond culture, the method of applying sufficient organic fertilizer and topdressing inorganic fertilizer is often adopted.
Apply more nitrogen fertilizer in the spring and more phosphorus fertilizer in the summer to promote nitrogen with phosphorus, so as to meet the absorption ratio of nitrogen and phosphorus by phytoplankton, but also not to over-enrich ammonia nitrogen.
(2) In the topdressing should be the inorganic fertilizer should be fully dissolved, choose to sprinkle evenly in the morning on a sunny day, and avoid turning on the aerator immediately after spilling, so that the nutrients can be fully absorbed by the phytoplankton.
8. The nitrite in the water body is high
Normal aquaculture water nitrite is generally not more than 0.1 mg / l is appropriate, too high nitrite in the water body will lead to a decrease in the amount of feeding of aquatic animals, gill tissue lesions, breathing difficulties, restlessness or slow response, severe outbreak of death, shrimp farming process "stealing death" is often caused by high nitrite.
In the middle and late stages of culture, the high nitrite in ponds is an extremely common phenomenon, which is related to the increase in feeding volume, the increase in biological and nitrogen stocks in the middle and late stages of culture, while the nitrifying bacteria themselves reproduce relatively slowly and their growth is easily inhibited by other flora.
For nitrites that are too high, the common prevention and control measures are as follows.
(1) Start the aerator or sprinkle the whole tank with chemical oxygenator to promote the conversion of nitrite to nitrate.
(2) The use of ammonia chelating agent, activated carbon, adsorbent, humic acid polymer and other combination of water quality adsorbent (such as nitrite degrader), through ion exchange, adsorption or degradation of nitrite.
(3) Use microbial preparations such as bacillus, nitrifying bacteria, photosynthetic bacteria, etc., and use live bacteria preparations to accelerate the decomposition and transformation of nitrite.
(4) Thin water body increases phosphate fertilizer, with calcium dihydrogen phosphate as the best, to promote the absorption of nitrogen by phytoplankton, and the partial fertilizer water body is sprinkled with zeolite powder or alum plus table salt in the whole pond.
(5) Timely discharge of water, especially the bottom water and sewage, and timely clean up the dirt in the pond.
(6) After disinfection and killing of anaerobic bacteria, adsorb with zeolite powder.