I'm not sure I have an answer but I do have some observations I can share. I first noticed in the heath food stores some pretty pink salt also some yucky grey salt and that was the first time that I really twigged that there was more than just rock salt or table salt. Up until then I hadn't given it much thought. I was at Harbourside butchers and they had these pink salt bowls - when I queried what they were for they said they were used to marinade meats. Then another day when I was buying chocolate I noticed yummy chocolates with pink crystals on top. I asked what they were and was told pink himalayan salt. That was enough for me to come home and google.
There are conflicting views out there - that's a surprise LOL. Some clean eaters don't use salt at all. Other experts claim that there is no difference salt is salt.
I've linked in here a few of the articles I have read so you can decide yourself.
Now that I know that hidden salt is out of our diet, I figure I know how much salt I am adding as I cook. I threw out our table salt and swapped the salt in our grinder for pink himalayan salt that I bought in a scoop from the health food store. It looks pretty and it's apparently good for you. In opposed to table salt pink salt contains the full spectrum of 84 minerals and trace elements. It also has no preservatives or additives and is processed without chemicals. I think that makes it pretty clean.
Interesting articles about salt