well some people use chemi clean. and then do a water change. BUt you need to figure out where its coming from, Poor lighting or old bulbs, Low flow in the tank overfeeds help with all of this.
I used a product called "red slime remover" made by ultralife. One dose and it killed it all off in 48 hours. Then a simple water change and your good to go. Reef safe as well. Works great just did it a week ago.