Thank you so much for this info. I have been out of town and just getting back on here. I put two grass carp in almost 2 years ago and they are huge now. I believe it has just taken the dye and the carp some time to catch up but it is slowly working. I don't think I will need to add another as the infestation seems to be mostly contained to the shallow water now as you said. I think I will continue raking it out here and there and reapply dye as needed.