This is a loaded question UF and I have gone rounds on already.
Salt can do a great many things....some good and some bad. What is it you are trying to achieve? What's the desired result? I have used a lot of salts, some as aid, some to treat, and some to disinfect.

In referance UF to our previous thread on this, I am testing both salts currently to guage the results. Nothing really interesting to report as of yet. Both swimming around like nothing is different. In consulting with my chemistry proff I had in college, he confirms your data (this is a good thing). Fisheries Biologist I know confirms your thoughts on using the wrong salt too. So I am diving deeper into this. So far, more than a month into tests and I am not detecting any problems. Doesn't mean there aren't any...I just haven't found them yet.

WARNING: I am not advocating anyone to just dump salt into their system. Educate yourself with your own research. That's what I am doing, and if it goes bad, you can only blame yourself. But if it goes great, you only reward yourself.

Best of luck.