I have at least one polyclad flatworm that has decimated my snail population. I caught a glimpse of it a few months ago but wasn't quick enough with the turkey baster. Speedy sucker hid in one of my rocks. Someone suggested I try Prazi-Pro, so I relocated my coco worm to a friend's tank and dosed the DT this morning. Now how do I know if it worked? Any suggestions?