I also had this in my tank and at one point it reached plague proportions. I used chemiclean which worked, but eventually it came back. Then, I made sure that I kept up with changing out my lamps and reduced the time the lights were on, and that solved the problem. Basically, you kinda have to figure out what is causing it, and then eliminate, or reduce, the cause. Like everything in the tank, this is really just a another natural tank flora....but when not kept in check, it can reach plague porportions.