It is not a pool with sea water and the salinity is not the same as in the sea.
It is a system that uses salt instead of chlorine to clean the pool water.
Sea water has a salt content of approximately 3.55%. The salt system works with a concentration of up to 0.40 %, i.e. about one tenth of what seawater has.
Pools that use salt for cleaning have several advantages over pools that use chlorine: they reduce eye irritation, dryness of the skin and help to revitalise the body's tissues and eliminate toxins. Another advantage is that they do not smell of chlorine.
As the density of salt water is higher than chlorinated water, these pools are also recommended for exercise and rehabilitation in case of accidents or injuries.