Sorry Stuart but imo deeming permanganate an option and not a mild dose of antibiotic (know to kill this stuff btw) is bad advice. Permanganate is not benign and I have seen whole ponds full of koi destroyed with it. TerryB _______________________________________________ Aquatic-Plants mailing list Aquatic-Plants at actwin_com http://www.actwin.com/mailman/listinfo/aquatic-plants