Strong sunshine and high outdoor temperatures now change the water colour of shrimp ponds frequently. This makes pond management harder, and ineffective handling adds extra cost.
The water turns to undesirable algae colours, such as blue-green algae, euglenoids and dinoflagellates, because:
- there are too many nutrients in the pond;
- feeding is not matched to the shrimp's actual needs, so leftover feed fouls the water;
- digestive probiotics are not used properly, so shrimp feces stay bulky and hard to siphon, fouling the water and causing slime on the pond liner;
- the microbes in the pond are not working well;
- the supply water carries toxic algae seed because it was not prepared thoroughly, so once it enters the pond, the algae multiply and bloom, changing the water colour.
How to keep toxic algae under control
- Prepare the supply water so it is free of toxic algae seed. Water going into the pond must be clear and free of acid sulfate (alum) contamination.
- Feed according to the shrimp's actual needs for their age (days of culture).
- Add quality digestive probiotics throughout the crop to limit bulky feces that make siphoning difficult.
- Use probiotics regularly, siphon thoroughly and check the pond bottom often.
- When the pond water turns a toxic algae colour, deal with it gradually according to the algae load. Avoid overusing chemicals or enzymes to clear algae quickly, as this easily leads to an algae crash, fouled gills and gut disease in the shrimp.
Thinning the algae
When thinning algae, reduce the feed. How much water to exchange depends on how dark the algae are.
- Use the probiotic MAX 4000 (227 g/1,500–2,000 m3 of water) 1–2 times in a row to help thin the algae, then reapply once every 4–5 days.
- Or use the probiotic SOILMAX (100 g/2,000–2,500 m3) at night, optionally together with quicklime (CaO) to speed up algae thinning.
- Give BIOMAX digestive probiotics at a high dose to help keep gut health stable during the bad-algae period.
- Keep using MAX 4000 / SOILMAX regularly throughout the crop for better management of the pond environment.
English text adapted from Than Vuong's original Vietnamese infographic.
