Patience with Ick. Salt and temp usually does it but it takes a week plus. Water changes and replenish salt. I have used reduced prescription quick cure with success on small bass but must be with water changes. Good luck.
ick doesnt just die at that temp lol, it will die at 85, it just depends, some ick can live longer in hotter water then others, guess it depends on the strain or whatever, and imo i wouldnt ever do more then 1 tablespoon per 5 gallons
also it will never be quickly gone lol, ick has 3 life stages, it takes a minimum of a week to fully get rid of ick, cause you have to kill them at a certain life stage as to where you cant kill them when in the other stages, so it takes a lil time