ICH cannot be eradicated in 3 days, and even if it falls off of your fish 3 days after you discover it, it is still alive in the tank. For more information try this link. As far as fish sensative to salt, if they can survive quick cure, they can certainly survive salt for the time it takes to treat ich.
http://www.aquariacentral.com/forums/showthread.php?t=39759
Dave
http://www.aquariacentral.com/forums/showthread.php?t=39759
Dave