I wish I could remember the kent addative I use at the moment, but it is the stuff in the blue bottle, and the liquid is blue. It contains a lot of elements, one being iodine. I have read in books about using iodine adative for proper molts as well. Anyway, I picked the kent addative that contains more than one specific element, and it seems to work well, it is supposed to be a growth inhibiter for corals.