How to distinguish between fat water and thin water?

1. Look at the water color: Generally speaking, fat water means that the pool water is yellowish brown or oily green, the water quality is viscous but not turbid, the transparency is moderate, and the water color changes obviously every day; Generally speaking, fine water means that the color of water is light, light green or light yellow, with great transparency and changing day by day.

2. Look at the index organisms: there are many plankton in the fertilizer water, and the dissolved oxygen in the pool is sufficient. The indicator organisms are diatoms and cryptoalgae, and rotifers have a large number of reproduction. This water is suitable for raising fish. The dissolved oxygen condition in the thin pool is good, but the number of plankton is small. The indicator organism is blue mud moss (filamentous algae reproduction).

3. Look at the downwind oil film: When it is difficult to observe the water bloom, the water quality can be judged according to the number, color and shape of the downwind oil film. There are many oil films in the fat pond, and the sticky foam changes daily, which is light brown in the morning and green in the afternoon (commonly known as "early red and late green"); On the contrary, it is a thin pond.

4. Look at the change of water color: the excellent water quality has monthly change (10 day, alternating light and shade for half a month) and daily change (morning and afternoon, upwind and downwind); The situation of poor water quality has not changed.

5. According to the visibility analysis: fix a brightly colored object at the front end of the tape measure and put it vertically into the water. If the object can be seen clearly below 50cm, it means that the water is thin, and the object can't be seen clearly below 30cm, which means water and fertilizer.