You should look for Aquarium salt, API makes a good one, don't use ocean/sea salt as it's completely different, and keep treating for ich since you've already started, it can only help kill the ich that's not attached to the fish yet.
When you say "put the filter back in" do you mean just the carbon, or the whole pad? If you mean the whole pad, then you probably lost your cycle from removing it and put it back immediately in hopes some BB survived, and if you meant the carbon, keep that out until you are done with the entire treatment. The only real use or carbon is to remove medications, so I never use it except for Adam after I finish medicating.
Oh, and with the aquarium salt, make sure that when you are doing water changes, only replace the amount of salt you removed, say you remove 5 gallons of water, only put 1 tsp back in, 10 gallons, 2tsp. Anything less than 5 gallons I wouldn't mess with adding more salt to. I don't know what your evaporation rate is like either, but make sure you are only adding water to top off (with conditioner of course) rather than more salt. What you put in the water doesn't evaporate with it.
I know that probably sounds like common sense, but you'd be surprised how many people don't realize it! Lol