Those are the exact brine lakes I talked about that exist in the bottom of the ocean.

Brine is too dense to be above seawater. They accumulate in the bottom, creating essentially small pockets that kills almost every normal life. Only extremophiles live near it, and even then its usually just surrounding the edges of the lake.

You also can’t exactly guarantee that the brine you make ends up here. They are in the bottom of the ocean, not exactly a place you can pump brine to.