FUTI Impeller Aerator

Impeller aerators are widely used in adult fish ponds, providing three essential functions: oxygenation, water stirring, and aeration. While these functions occur simultaneously during operation, their prominence may vary depending on specific conditions. Below is a detailed look at the three functions and their benefits:

1. Oxygenation Efficiency

Impeller aerators typically increase dissolved oxygen levels in fish ponds by 1.0 to 1.5 kg/kW·h. However, when used in larger ponds (1.5 to 3.0 mu/kW·h), the oxygenation effect is distributed unevenly, and only a localized area around the aerator maintains high dissolved oxygen levels. This can help fish survive by creating a zone with sufficient oxygen, though the overall pond might not see a quick boost in oxygen levels.

For optimal results, aerators should be activated before oxygen levels drop too low. In fish farming, a dissolved oxygen level of 2 mg/L serves as a warning line to start aeration, and behavioral cues from tilapia or wild fish (such as surfacing for air) can act as biological indicators for aerator use.

In smaller ponds, or when the aerator load is lighter (0.8-1.2 mu/kW·h), the aerator shows more effective and uniform oxygenation across the pond, enhancing the pond’s overall health.

2. Water Stirring for Uniform Distribution

Impeller aerators excel in water stirring, promoting rapid mixing of water layers and refreshing the liquid surface. This equalizes water temperature and dissolved oxygen levels throughout the pond. On sunny days, the temperature and oxygen differences between the upper and lower layers of the pond are most pronounced, especially at noon. In such conditions, the aerator’s stirring effect ensures a quicker circulation of water, shortening the time it takes to balance the oxygen levels across all layers. The smaller the pond, the quicker the circulation process, which enhances the aerator’s efficiency.

3. Aeration and Harmful Gas Removal

When an impeller aerator operates, it promotes the release of dissolved gases from the water’s surface through splashing and liquid surface renewal. The escape of gases is directly proportional to their concentration in the water. Harmful gases like hydrogen sulfide and ammonia, which accumulate in the lower water layers, are expelled faster when the aerator is turned on, improving water quality. A noticeable fishy odor may occur during this process, indicating the removal of these gases.

While the aerator can slightly accelerate the escape of dissolved oxygen, its strong water stirring capabilities ensure that most oxygen is circulated to the lower layers, minimizing oxygen loss. Research shows that dissolved oxygen loss is about 0.77 kg O₂/kW·h, which is relatively low compared to the overall oxygen transfer to deeper water layers.

Impeller aerators are vital tools for maintaining the health of fish ponds. By improving oxygen levels, promoting uniform water distribution, and expelling harmful gases, they help ensure an optimal environment for fish farming. For best results, monitor the pond conditions and activate the aerator at appropriate times to maximize its benefits.

Best Practices for Using Aerators in Intensive Fish Ponds

Aerators are now widely used in intensive fish ponds across the country, but many are not maximizing their effectiveness. The common practice of only turning on aerators when fish begin to “float” due to low oxygen levels turns the aerator into a mere “fish rescue machine.” To transform the aerator into an efficient “oxygen increasing machine,” the following methods should be implemented:

1. Targeted Aerator Usage Based on Weather Conditions

To prevent fish hypoxia, the reasons for low dissolved oxygen caused by different weather patterns must be understood and the aerator should be used strategically. Here’s how to optimize aerator usage for different conditions:

• Sunny Days: On sunny days, the primary cause of hypoxia in the morning is the vertical differences in dissolved oxygen between the upper and lower water layers. The upper water warms up and has higher oxygen levels due to photosynthesis, while the cooler, denser lower layer remains oxygen-deficient. As night falls, when the upper water cools and mixes with the lower water, oxygen levels can drop significantly, leading to fish floating heads.Solution: Properly turning on the aerator at noon on a sunny day helps mix the upper and lower water layers, transferring supersaturated oxygen from the upper layer to the lower layer. This ensures that the lower layer receives enough oxygen to reduce its oxygen consumption. Although upper water oxygen levels may temporarily decrease, photosynthesis in the afternoon replenishes them, keeping the pond’s oxygen levels stable through the night. Using aerators at noon also accelerates the decomposition of organic matter and the circulation of nutrients, improving water quality during peak fish growing seasons.
• Cloudy or Rainy Days: Cloudy and rainy days often lead to low dissolved oxygen due to reduced phytoplankton photosynthesis, meaning less oxygen production and increased oxygen consumption.Solution: On such days, aerators should be turned on early to prevent oxygen depletion. Use predictive technology to anticipate fish floating heads and increase oxygen levels before hypoxia occurs. The aerator should always be activated before fish begin floating due to low oxygen.
• Avoid Turning on Aerators in the Evening: On sunny days, turning on the aerator in the evening can mix the water layers prematurely, leading to increased oxygen consumption. This can have the same negative effect as an evening thunderstorm, causing fish floating heads. Therefore, avoid operating aerators in the evening, especially on clear days.
• Rainy Noon Activation: Activating aerators at noon on rainy days may do more harm than good. It can reduce phytoplankton oxygen production in the upper layer and speed up oxygen consumption in the lower layer, increasing the likelihood of floating heads.

2. Flexible and Intelligent Aerator Use

The timing and duration of aerator operation should not be rigid but instead, flexible based on factors such as climate, pond conditions, water temperature, feed and fertilizer levels, and the aerator’s power. Use the following guidelines for more efficient operation:

• Best Times to Operate Aerators:
  • Noon on sunny days.
  • Early morning on cloudy days.
  • Midnight during continuous rain.
  • Avoid turning on in the evening.
  • Start aerators early when fish floating heads are predicted.
• Adjusting Operating Time:
  • Longer operation times are recommended at midnight, and shorter times at noon.
  • In hot weather, or for larger water bodies, extend the operating time.
  • In cooler weather or for smaller ponds, reduce the operating time.

By understanding pond conditions and dissolved oxygen fluctuations, aerators can be used more effectively to promote fish health and growth while preventing hypoxia.

Conclusion

To optimize the use of aerators in fish ponds, it’s crucial to adopt a proactive approach rather than waiting for fish floating heads to occur. By considering weather conditions, pond size, and oxygen needs, you can ensure that aerators provide consistent oxygenation, improve water quality, and enhance fish growth. Incorporating predictive technology can also help fine-tune aerator usage, reducing fish stress and improving the overall efficiency of your aquaculture system.