Look at the color of the water. Generally speaking, oil green, yellow-green, brown-green, tea green, and green-brown are fertilizers; water is light, and the water color is light green, dark green, and blue-green. It is thin water; the brown color of the water is a sign of deterioration of water quality. Water and other measures have been improved.
Second, look at the daily changes in the color of water. If there is transparency in the morning in one day, the water color is light, the transparency in the afternoon is small, and the water color changes. This is a good water for fish farming. In addition, the general fat pond has more oil film downwind and is brownish in the morning and greenish in the afternoon.
Third, look at the transparency of water. The transparency of fertilizer ponds is generally between 20-40 cm, less than 20 cm or greater than 40 cm, indicating that the water quality is too fat or too thin.
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