Just an FYI....To expect temperature alone to cure ich, you usually would have to have it above 86. Around 85 - 86 ich will stop reproducing, but will not actually be killed, but theoretically over time since they are no longer reproducing they will all die off. A cycle of ich is usually around a week depending on temperature. I would go two weeks with no symptoms to be sure. If you have a qt tank you can easily use, it may be worthwhile to remove the fish that have signs of ich and treat them with meds seperately just to make sure you get rid of it. Each cyst that falls off an infected fish can produce thousands of free swimming parasites after it hatches in the gravel.