I saw a couple of very small white flatworms in the corner of my tank at the bottom near the sand tonight. I cannot see any on my corals and all my acros look great. My question is.. are there some flatworms that do not cause a threat? Also would it be a good idea to use flat worm exit just to be safe before they got to a lvl that the die off could be toxic? does the flatworm treatment harm anything or is it just the flatworm die off that is bad?