In recent years, as the focus of aquaculture industry, recirculating aquaculture model has developed in full swing throughout the country. However, for most practitioners, they always feel that the circulating aquaculture model around them is less and more. This feeling is not groundless, comprehensive analysis of the reasons, because the circulating water aquaculture model is different from the traditional outside pond aquaculture model, has the characteristics of multi-disciplinary, high technical threshold.
Among the key factors that determine the success or failure of a circulating water system, one is particularly critical: the effectiveness of the biobank. The efficacy of the biological bucket is directly affected by the maturation of biological fillers, this paper will introduce a "non-inoculated strain type" nitrification system culture method, welcome colleagues to correct and exchange.
Nitrification system culture method (no strain type)
1. Prepare two breeding ponds (cement ponds, canvas ponds can be), the size of 6m×6m×1.2m, each pond must have 4 side aeration and more than 6 bottom aeration;
2. Measure the water quality index of the aquaculture raw water. If there are heavy metal ions, remove them with EDTA and other reagents; The initial ammonia nitrogen and salt indexes were recorded;
3. Fill the raw water for aquaculture that does not contain heavy metal ions into the two aquaculture tanks at a height of 70cm to ensure that the total water body of each pool is about 20t; Open the aeration switch and fully aerate for 24h to prepare for the filling into the tank;
4. Pour 5m³ filler into two breeding ponds respectively, requiring the filler to be evenly distributed on the water surface without local accumulation; The filler should not be too much, and the volume of the filler and the volume of the water should be between 1/4 and 1/3;
5. Close the side aeration, only open the bottom aeration, and adjust the air flow to the maximum to ensure that the filler can fully roll; Add 500g of shrimp ingredients to each pool and sprinkle as evenly as possible;
6. In the first week, add 300g urea and 600g brown sugar to each pool every day, and evenly sprinkle; Urea can be replaced by ammonium chloride, brown sugar can be replaced by white sugar; Daily measurement of ammonia nitrogen data, recorded;
7. In the second week, open the side aeration for 24h; Reduce the bottom aeration rate to ensure that the filler can roll up and down; Add 400g of urea and 800g of baking soda to each pool every day; Test the index of ammonia nitrogen, if it reaches about 30, you can suspend the input of urea;
8. From the third week until the end of culture, the added amount of baking soda is 1000g per pool per day; Test the data of ammonia nitrogen and subsalt every day: if there is a steep drop of ammonia nitrogen index and a steep rise of subsalt index, it is proved that the maturation of nitrogenous bacteria group, which takes 1-1.5 months;
9. From the fourth week, the nitrate index is measured once a week. If the nitrate appears and obviously accumulates, it proves that the nitrifying bacteria group ripening, which takes 1.5 to 2 months;
10. The filler can be moved into the biological tank after ripening. If you need to wait a long time before using, add 500g urea and 1000g baking soda once a week.