The white powder that crab vendors add to crab water may be sea crystal, and its main component is sea salt, which is used to imitate the composition of seawater to cultivate seafood. This practice has existed in Qingdao, Dalian and other coastal cities for 10 years, and it is not harmful to human body.
However, please note that if the configuration is not proper, it may have an impact on the survival rate of seafood, so it is recommended to choose a reliable seller when purchasing.