Is this a plausible phenomena for an alien ocean?

So, the oceans in this world have something in them that makes it non drinkable, like salt here. However there is a method in the story on which the "salt" is gathered through evaporation and mixed with more ocean water. As it gets saturated, some of the "salt" remains as sediment and slowly begins to attract and "crystallize" the rest of it, drastically lowering the amount it contains. Kind of like how water can crystallize rapidly into ice with impurity present or how reusable hand warmers work but not quite

.... Is there anything that could explain such a reaction? Btw, I was thinking that the reaction sometimes happens spontaneously too, creating different densities in the water and thus currents and climate shenanigans. I know there could be suspension of disbeleif but still