My dau gave me a frag of zoas for xmas. It has 2 types of algae on it, and one polyp has a purplish coating on it. How do I get rid of the algae. I've read some posts on the internet about dipping in peroxide. don't want the stuff to spread into my tank. For CUC I have 3 cerith and 2 turbans. No one has touched it.