Curious about salt in water softener
We just had a water softener installed. I just noticed the local grocery carries "regular" salt and salt that is supposed to help deal with "rust." Iron in the water is a common problem around here.
Anyway I wondered what the chemical difference is between the two kinds of salt. None of the websites I visited would say, only that it was an "FDA Approved additive" for the iron.
Can anyone enlighten me?
And how useful is the additive?