Application methods of "live water" in the aquaculture industry

The fundamental method and ultimate goal of water quality control in aquaculture is to cultivate "live water," eliminate "oxygen debt," fundamentally solve the bottleneck problem of dissolved oxygen, promote the healthy and rapid growth of aquatic animals, reduce production costs and energy consumption, improve product quality and safety, and enhance the economic benefits of aquaculture.

1. Choose spacious aquaculture water bodies and design reasonable aquaculture structures. 
The application of "live water" in aquaculture aims to solve the hypoxia at the bottom of the aquaculture water body, eliminate "oxygen debt," and avoid risks such as "floating heads" and "ponds overflowing" in aquaculture. The key to "live water" is to continuously maintain a micro-circulation flow state in the aquaculture water body. If the water body space is too narrow or there are many obstacles in the aquaculture water body, the "live water" in micro-circulation will constantly encounter resistance and come to a standstill, making it difficult to maintain the "live water" state. In such water bodies, maintaining the "live water" state would require excessive energy consumption. Therefore, the water body used for "live water" aquaculture must be spacious with ample water area and free of obstacles. 
At the same time, to leverage the advantage of higher dissolved oxygen at the bottom in the "live water" state, it is particularly important to select economically valuable benthic marine and freshwater aquaculture species such as fish, shrimp, shellfish, crabs, and turtles, such as mandarin fish, yellow catfish, and whiteleg shrimp. Therefore, in water bodies where aquatic plants must be planted or nets set up, it is not advisable to use the "live water" method for species like river crabs, green shrimp, and crayfish.   

2. Design and adopt energy-saving methods to create inexpensive "live water." 
Factory-style flow aquaculture or large-scale oxygenation machinery can create "live water," solve the bottleneck problem of dissolved oxygen in aquaculture water bodies, and improve the aquaculture capacity and economic benefits per unit of water body. However, both scenarios lead to high energy consumption and high costs, which are not suitable for China's national conditions and the development trend of the global aquaculture industry. Only by forming physical "live water" (micro-circulation flow) under low energy consumption can it be widely promoted and applied in China and even globally. This must be based on the fluid dynamics characteristics of water as a special liquid, selecting simple and energy-saving mechanical methods to create "live water." 
Water, as a typical liquid (fluid), has the following physical characteristics. First, it has high inertia. The density of water is 772 times that of air, and once water is in motion, it contains rich kinetic energy and has enormous inertia. Therefore, rivers continue to flow forward as they enter plains, floods are like ferocious beasts, and tsunamis can devastate everything. Second, it has low friction. Moving water does not consume a lot of energy due to molecular friction, allowing it to maintain a continuous motion state. Ships sailing in the ocean can still travel several kilometers or even tens of kilometers after removing their power. Third, it has strong plasticity. When flowing water encounters obstacles, it does not stop like a solid but changes direction and continues forward. Fourth, the energy of slowly flowing water does not easily dissipate. Liquids only produce "turbulence" and cause additional energy loss when exceeding a certain speed. 
Therefore, despite the rapid advancements in technology worldwide, the aforementioned fluid dynamics characteristics of water determine that river and sea transport remain the most economical means of transportation today. New types of live water machines (also known as tillage water machines) can create physical state continuous "live water (micro-circulation flowing water)" with extremely low energy consumption by increasing the amount of water drawn and reducing the speed of drawing water, driving other physical, chemical, and biological processes in the aquaculture water body, making the aquaculture water body a "live water" that maintains a state of motion and vigorous life activities.

3. Remove excessive sediment to lay a good foundation for creating "live water"      
Current aquaculture methods are all high investment, high output, and high-risk production methods. Every year, a large amount of residual feed, feces, and organic matter from dead organisms accumulate at the bottom of the water, becoming the main source of "oxygen debt" in the aquaculture water body and the root cause of "floating heads" and "pond overflow" accidents. If the pond is not cleaned for several years, sediment will accumulate significantly, causing the aquaculture water body to remain in a state of hypoxia or low oxygen for a long time during the production season. This highly eutrophic water quality, even classified as inferior V type black and odorous water, is unsuitable for most aquatic organisms, rendering the creation of "live water" meaningless. 
Therefore, for ponds and other water bodies that have been farmed for many years, first, thorough dredging is required. During the winter and spring aquaculture leisure season, the accumulated sediment of organic matter over the years should be excavated. Second, the aquaculture water body during winter should be drained in a timely manner, and after deep plowing, or through "wind blowing, sun exposure, and night freezing," the organic matter in the bottom sediment should be fully oxidized and reduced. Third, use oxidizing disinfectants. For example, using quicklime, bleaching powder, strong chlorine, chlorine dioxide, and other strong oxidizing disinfectants can rapidly oxidize the organic matter in the bottom sediment. The above measures can prevent the organic matter in the sediment from consuming oxygen during the aquaculture process, thereby reducing the "total oxygen debt." This is the primary measure for creating "live water" and scientifically regulating aquaculture water quality.

4. Utilize microbial action to enhance ecological activity. 
Phytoplankton and beneficial bacteria play an extremely important role in the ecological cycle of material transformation and energy conversion in aquaculture water bodies. Natural water bodies have low organic matter input, low biological density, and good diversity, allowing for self-purification and maintenance of dynamic balance. In contrast, aquaculture water bodies, as artificial ecosystems, have fewer biological species, a wide variety of inputs, high intensity, and high levels of human intervention, resulting in poor ecological stability. It is essential to leverage the key role of microorganisms in the material cycle and energy conversion in the water body to ensure that the aquaculture ecosystem operates efficiently. 
Therefore, in aquaculture water bodies, it is necessary to timely supplement the two types of microorganisms, phytoplankton and beneficial bacteria, that have diminished or disappeared, to maintain their high density and strong vitality in the aquaculture water body. On one hand, this can be achieved through timely water replenishment and water changes to realize the variety renewal and old-new alternation of phytoplankton, or by using specialized unicellular algae to supplement their numbers and update varieties. The use of micro-ecological preparations has now become basically mature, mainly by selectively using beneficial bacteria such as Bacillus, lactic acid bacteria, photosynthetic bacteria, yeast, and actinomycetes, to achieve a high density of beneficial bacteria in the aquaculture water body, quickly complete the degradation of organic matter, and prevent the accumulation of "oxygen debt" caused by organic matter deposition. Since microorganisms lack mobility, they can only rely on the movement of the water body to achieve positional transfer. To enhance the effectiveness of micro-ecological preparations, it is essential to rely on the "live water" state of micro-circulation flow, allowing beneficial bacteria to continuously obtain organic matter and dissolved oxygen, fully and "actively" purifying the water quality. Therefore, the optimal effectiveness and best results of micro-ecological preparations in purifying water quality depend on the continuous supply of organic matter and dissolved oxygen by "live water."  

5. Reasonably set up "live water" machinery to prevent aquaculture risks. 
According to experiments, a general 60-90 watt aerator (also known as a tiller) can support a fish farming area of 5-8 acres. The shape of the water body is best square or round, and the depth of the water should be 1.5-2.5 meters, providing enough space to maximize the aerator's "live water" function, achieving a slow circulation of water throughout the entire body (entire surface, entire layer), bringing the rich dissolved oxygen from the surface to the bottom, while transporting the rich organic matter from the bottom to the upper layer and surface, thus rapidly "oxidizing and reducing" the organic matter that has long been deposited at the bottom and in the sludge. 
Therefore, if an aerator (also known as a tiller) is used for the first time in a fish farming water body that has not been dredged for several years, during the initial period of using the "live water" machine (within 5-7 days), it will accelerate the repayment of the "oxygen debt" that has accumulated over the years, undoubtedly leading to a rapid increase in oxygen consumption, causing the dissolved oxygen in the farming water area to be in a state of "insufficient supply," making it easy to experience "floating heads" or "pond blooming." The disposal method is to continuously operate the aerator (also known as a tiller) while simultaneously running oxygenation machines 24 hours a day for 5-7 days to supplement the dissolved oxygen deficiency caused by the accelerated repayment of the "oxygen debt"; another method is to use chemical oxygen enhancers, such as "granular oxygen" and hydrogen peroxide, on the 1st, 3rd, and 5th days while continuously operating the aerator (also known as a tiller) to quickly digest the long-term accumulated "oxygen debt" and prevent risks during the initial use of the aerator (also known as a tiller). If it is a newly built or recently dredged fish farming water body, the above operations are not necessary.