What are the strange phenomena in Yintianchi, Guangxi?

Among the mountains at the junction of Fusui County and Shangsi County in Guangxi, there is a mountain with an altitude of more than 500 meters. Silver Tianchi is located on this mountain. It is a circular pool like a crater.

Yin Tianchi is not too big, the water surface area is only about 10 mu, the water beside the pool is clear and transparent, and the water in the pool is dark blue and bottomless.

The difference between Yintianchi and other pools is that whenever the rainy season comes, the water level in the pool drops, and the more rainfall, the lower the water level drops. When the dry season comes, the water level in the pool will rise. The drier it is, the higher the water level will rise and even overflow the pool mouth. This is really a strange pool, but no one knows why this phenomenon occurs.