I disagree. u have to treat ur original tank as well. Actually, I don't see a reason for a quarantine tank. Why wouldn't u just get rid of all ick at once rather then dealing with 2 separate systems?
I had ick with corries and live plants including a moss ball. What worked for me with no stress to any animals, plants or bio-filter was Metronidazole. It's safe for everything, even a snail, and doesn't stain water. People say it's best to feed it rather then just dump the powder in water. i had a pretty bad case, especially on my pleco, and i completely eliminated the problem with just one round of dumping, not feeding. I'm sure other things work too, but i can tell you what didn't do the trick for me - Kordon Ich attack and QuickCure.
1. Finish the heat treatment. As I said, I don't see a reason for the quarantine tank. But if you wanna use it, change water and raise temp + salt in the original tank too. I didn't get if your main tank doesn't have gravel or the quarantine one, but either way if u have any gravel u gotta vacuum it. if not - less work for you :)
2. If the heat treatment works then great. if not then dose the entire tank with medication