I heard that raising the temperature does not kill the ich parasite, but speeds along their life cycle. so they go from parasite on fish, to protected incubator stuck on plants or gravel dividing into hundreds of new parasites (both life cycles cannot be killed without killing fish), finally to free floating babies which seek a host (fish). This is the only point in which they can be killed. I would suggest moving your fish to a quarentine tank. Then, slowly raise the temperature to about 83-84F. Then, slowly add 1tsp uniodized salt (aquarium salt or pure sea salt) to the water. by slowly I mean over several days. The salt kills the ich while they are free floating. And by speeding up their life cycle, you can kill them all faster. Keep the fish in 83F water with the full dose of salt for at least 2-3 weeks. Then you can be sure every last ich parasite is dead!! When you reintroduce your fish to their orrigional home, they will Never get ick again. Just be sure to quarentine new fish (without salt for at least 4 weeks, or with it for 2-3) and watch to make sure they are healthy. It doesn't hurt to quarentine new plants or inverts for a few days in a seperate tank, either (without salt).