What does salt in water mean in practice?
The common term may mean sodium chloride or the sum of many dissolved salts that make up the conductivity and TDS.
When does it matter?
The salty taste does not reveal the full composition, and the softener changes the type of ions without removing the total amount of salt.
Which solutions are related to it?
Conductivity, chloride, sodium and other major ions are determined, and a membrane process is used to reduce salinity.