I did not have any plant issues with QuickCure, which - although I suppose it may be molecularly different as Tracey indicates-does have the same 2 ingredients as ProForm C (formalin and malachite green) I thought I noticed some browing of the larger, older water hyacinth leaves-but this may have been a coincidence as these things were growing leaps and bounds at the time. The new foliage looks great. Also it did not hurt the frogs in my pond for which I was VERY grateful,