I treated my tank with flatworm exit today after doing lots of research; there's a several page thread on reefcentral that covers several peoples' experiences with this. I guess the trick is to siphon out as many flatworms as possible before treating, which I spent several hours doing before adding the stuff. Almost immediately after treating, I saw hundreds of more flatworms coming off the rocks and sand, dying quickly. That stuff is really fast; by the time I counted 150 drops in the sump and looked up in the main tank, most of the flatworms had already died. So, I got the siphon out and got rid of them, too. Then, I ran 2 lbs of carbon in a canister I made specifically for this. (about 12" tall 4" diameter acrylic tube completely filled with carbon) This was about 6 hrs ago, so far everything looks normal; at first my anemone retracted quite a bit, but it seems to be back to normal. I'll keep the carbon going for a couple of days. Maybe tomorrow I'll change 30% water.

After hearing the horror stories, and witnessing one, I was pretty apprehensive about treating for flatworms. But, so far, so good.

Matt