if the tank is ok then allowing her back in the tank may be the best thing for her, at the end of the day it is your call to make if you feel that she would be better of tubbed that is up to you, the reason I say to put her back in the tank is because it will be less stressful then daily water changes, also if all the fungus has fallen off then it would be just as stressful to continue salt baths, perhaps having catappa/almond leaves in the water would be more beneficially as a anti-bacterial.
I can understand if you are unsure of tank capacity it can be quite daunting not being sure on amounts. I use a 25litre bucket myself to do water changes and going from one room to another repeatedly does make your arm/hand ache. when I'm refiling I measure and dissolve any salts and minerals into the bucket before adding to the tank.