Application of water quality sensor in detecting water quality pH value in aquaculture
The pH value is an important indicator of water quality, which determines many chemical and biological processes in the water body, so the pH value has always been considered as a barometer of water quality. Too high or too low a pH value has direct harm to fish and shrimp. If the pH value is too low, the pH value of the blood of the fish and shrimp will drop, weakening its oxygen carrying capacity, and causing physiological hypoxia of the fish and shrimp. At this time, although the dissolved oxygen in the water is sufficient, the fish and shrimp will still float due to physiological hypoxia. and stop eating. If the pH value is too high, the gill tissue will be corroded, which can cause a large number of fish and shrimp to die. If the pH value is too high or too low, the microbial activities in the water will be inhibited, making it difficult for organic substances to decompose. When the pH value is higher than 8.0, a large amount of ionic ammonia will be converted into toxic NH3; when it is lower than 6.0, more than 90% of the sulfide in the water will exist in the form of H2S, increasing the toxicity of the sulfide. Fish and shrimp cannot survive when the pH value is lower than 4.0 or higher than 10.6.
Control of pH value:
The pH value between 7.7-8.8 is more conducive to the growth of fish and shrimp, so the pH value must be monitored and regulated during the breeding process.
1. Adjustment before seedling release If the pH value is higher than 9.0 (measured around 10:00 in the morning), the survival rate of fish and shrimp fry will be greatly affected, so pH adjustment before seedling release is an important part of breeding work . For regulation, the method of applying acidic chemical substances, such as adding appropriate amount of acetic acid, citric acid, oxalic acid, etc., can also change the water or inject new water (underground deep well water is better), and try to reduce the pH value to below 9.0 (above 8.5) , which can ensure that the survival rate of fish and shrimp seedlings after releasing seedlings meets the production requirements.
2. During the first two-thirds of the whole breeding process, the various indicators of water quality are generally relatively normal, such as the concentration of NH3 and H2S is very low, and the adverse effects on the prawns are very small. At this time, you can rest assured and boldly Control the pH value in the most suitable range for the growth of fish and shrimp. Subsequently, the pH value gradually decreased. If the pH value measured at 10 am is below 8.0, it should be adjusted in time. 20ppm quicklime can increase the pH value by 0.5.
3. In the mid-to-late stage of fish and shrimp farming, the various indicators of water quality are already very poor, especially in the case of high-density farming, the concentration of NH3 and H2S will inevitably rise or even exceed the standard, and the pH value will drop very quickly. If the pH value is not adjusted properly at the time, even if the aerator runs continuously at full capacity, there will still be a danger of physiological anoxic floating heads for fish and shrimp, causing unnecessary losses to the breeder, so the pH value adjustment technology in the middle and later stages The requirements are relatively high, and it is also the key link to determine the quality of the breeding effect.
