i have 2-250w stealth heaters on my 150 and it takes a day or two to go up to 88* but stay away from chems. rough fish (fish without scales) especially loaches cannot tolerate some chems. It may take a few days before you see an improvement. i'd leave them in the main tank and do your ich treatment in there because the ich is already in there. if you Q them and put them back, you may be putting them back into an ich infested tank. give it time