Due to the effects of ocean currents and tides, the elements in seawater are relatively balanced.

For example: in areas with low salinity, due to the large amount of fresh water emissions, the corresponding ions are also relatively reduced. Due to the influence of tides, although the amount of ions is reduced, it is relatively balanced. Similarly, the high salinity of the deep sea, each ion index is high, between the ions is balanced.

The ion content of the inland seas will vary slightly due to differences in geology, and the reason for the balance is the large circulation of ocean currents.