Get a few wrasses of the halichoers species.. the more, the better.. When in a situation like yours, natural methods are best.. Also, blowing affected corals with a turkey baster 1 to 2 times a week when fish are hungry will help you out.. Another wrassse that will gobble them up once in the water cloumn is the salon fairy wrasse. Good luck to you.. It is my recomendation after trying it myself to not attempt any in-tank treatments..