Is seawater poisonous in the Millennium solar terms?

I have never heard of this statement, and seawater is not a chemical reaction equation. Toxic in season, non-toxic after season.

However, the weather in the Millennium season is complex and changeable, and the temperature difference between day and night is large. The reproduction speed of pathogenic microorganisms is accelerated, and bacteria are swallowed by fish and shrimp with food, resulting in disease variation of fish and shrimp. Strengthening water quality management is a special season for aquaculture.