The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Speaking from first hand experience, it won't kill your reef and it won't kill your Ich either. I tried this stuff out when I was a newbie. You need to kill ich with copper or hyposalinity. Or.... just keep a properly sized tank for your fish with pristine water conditions and plenty of healthy food and the fishes will be able to fight off the ich on their own. At that time the ich may still be in the water, however, the fishes own immune system prevents it from becomming an issue.