I hope it is not too late and the reply will help...
I lowered the amount of salt from 2 t.spoons to 1.5 and lowered the temp. to 27. I lost that one that was at the bottom that day...but the other one servived. I did small amount of water change (keeping the amount of salt 1.5) every day, vacuum the bottom. I terned of the light of the aquarium keeping the light in the room. It took about a week to get rid of white spots