Bill
NO!!!!!!!!!!!
Salt and this Calgon(or Calgon wanna bee) are TWO different animals.
The Calgon takes minerals out of your clothing if you use it in your laundry, I have very hard water here at the stick built and the Calgon assists in keeping the whites from getting yellow.
Have no idea what salt might do down there, but, IMHO, it would not be good, might even be ugly!
Not sure the intended results of using the Calgon in the holding tanks, but believe it is to help keep em slippery, so stuff does not stick to the stupid sensors. Personally we don't use it for that reason at all, we use it to keep the ickies from building up. We use it to float out the soap scum and food particles.