How many days does the shrimp pond use calcium chloride magnesium potassium?

Within 5-7 days after sowing, spray a small dose of calcium-magnesium mineral crystals along the pond at 6-8 pm every day. Calcium supplementation in advance is the concentrated molting period of prawns on the first day, fifteenth day (tidal gravity) and twenty-four solar terms (solar terms alternate) of the first lunar month. It is suggested that crustaceans should supplement calcium and magnesium minerals two days before the molting concentration period of shrimp, lobster and crab.