Under normal circumstances, nitrite in water should be controlled within 0. 1 mg/L. Ways to reduce:
(1) aeration, aeration, increase dissolved oxygen in water (insist on turning on the aerator for one to two hours at noon on sunny days), so that the chemical reaction will proceed in the direction of nitrate.
② Add good fresh water into the pool.
③ Keep the PH value of the pool water above 7.0, and maintain a high level of hard water and chloride.
④ Use chemical or biological agents to adjust water quality, such as zeolite powder and diammonium chloride.
Causes and harm of excessive nitrite in make-up water
Nitrite is an intermediate product of nitrification of ammonia nitrogen, which is formed by the oxidation process of nitrite and NH4+ through nitrifying bacteria in the absence of oxygen. When the concentration of nitrite reaches 0. 1 mg/L, fish blood turns chocolate, which is called "brown blood disease", which makes fish gills swollen, food intake decrease, growth slow and diseases increase. When it reached 2.5 mg/L, the fish was poisoned due to insufficient physiological and metabolic functions, and its respiratory function decreased, its physical strength weakened, and the whole pool broke out and died.