How to identify good and bad water color in aquaculture ponds

1. Brownish yellow (tea color):The water has a yellow-brown color due to the growth of Bacillariophyta, which thrives in brackish and salty water environments at the beginning of the farming season. This is the most suitable water color for farming brackish and salty aquatic species.

2. Light green water (young banana shoots): The light green color is due to the growth of green algae (chlorophyta), which thrives in freshwater or lightly brackish water (below 10 parts per thousand).

This is also the most suitable water color for aquaculture. Green algae, in addition to playing an important role in the food chain, also has the effect of stabilizing the hydrochemical factors in the pond, absorbing organic substances, thereby reducing the amount of toxic gases in the pond. Farmers should try to maintain a light green water color, so that aquatic species will grow better.

3. Dark green water (moss green)): The dark blue color of water is due to the growth of blue-green algae (Cyanophyta), which thrives in fresh, brackish, and salt water environments.

If the water in the pond has this color, it is necessary to take measures to reduce the amount of algae, because this type of algae is not good for aquatic species. Moreover, if blue-green algae grow too much, it can secrete toxins that kill fish. In addition, it can also cause oxygen deficiency at night due to excessive algal respiration.

4. Orange yellow (rust color): This color often appears in newly dug ponds on acid sulfate soil. The orange color is due to the potential acid sulfate soil (FeS2) being oxidized to form iron scum.

For ponds with orange-yellow water, it is necessary to take measures to remove alum before stocking. You can use agricultural lime or pump and drain water many times to wash away the alum in the pond. For ponds that are being raised, lime should be spread on the pond banks to avoid the phenomenon of pH suddenly dropping when it rains.

5. Brick red (red soil color): Water with a lot of alluvium due to eroded sand and soil from upstream areas being carried by water to downstream areas; often occurs when a flood is about to come.

Farmers should note that they should not add water to the pond at this time, because the large amount of silt will make it difficult for shrimp and fish to breathe and reduce their ability to catch prey. It is best to add water to the settling pond before supplying it to the farming ponds.

6. Dark brown: The water is dark brown because it contains a lot of organic matter. This water color is often seen in ponds with poor water supply and drainage systems, poor environmental management during the farming process, and excessive feeding will easily cause the pond water to be dark brown. In this case, the dissolved oxygen content is very low, so immediate treatment is needed.

You can change the water many times until the brown-black color is gone, or combine it with biological products and chemicals that can absorb toxic gases. In addition, if you see that shrimp and fish have a lack of oxygen, you need to use a fan to stir the water or chemicals to provide oxygen immediately to minimize damage.

Ngoc Anh