Three kilograms. The ratio of shrimp sea crystal to fresh water is 3 kg per 100 kg of fresh water. Sea crystal is the product of seawater and salt chemical industry, which is mainly produced through a series of evaporation, centrifugation and concentration processes of seawater or brine. Sea crystals are white or pale white particles with no peculiar smell. They are mainly composed of sodium chloride, magnesium sulfate, magnesium chloride and calcium chloride.