For very small outbreaks, you can spot treat (pull out and use some kalk paste (or f aiptasia) to kill the roots. I had several outbreaks that went far beyond this and used Flux Rx. Both times it came back from some of the deep rock areas but the 2nd time i was able to spot treat and didn't have to use Flux Rx again. Flux didn't hurt any corals, inverts or fish - it's just a pain to do with no water changes, turn off your UV, skimmer etc.