I feel some of your pain. That being said, I dosed 4 grams. 2 grams on Super bowl Sunday and 2 more grams the next day. I have a 180 gallon reef. 2 weeks later I started to put carbon and poly filter pads along with big water change. 2-30 gallon changes within a week of each other. I was hoping this routine would pull out much or all of the fenben. Started adding snails. They’re thankfully doing great. Added a small leather it’s still closed after two weeks. My zoas in the tank that were present during the dosing are coming back. I’m doing another water change tomorrow. Fyi. no blue clove polyps have returned. Yay! Good luck.These things are driving me crazy. I tried one dose of the fenbendazole last year. It melted them for a little while, but I couldn't put in any softies, shrooms, invertebrates, and zoos for almost 3-4 months. These guys still came. I have been hesitant to add more since I'm worried about the long term affects. I've been trying to manually tackle them by 1) completely removing rocks (without corals) with them on it and baking and drying them out in the sun, 2) removing corals from rocks that have them; 3) scrubbing the cloves off the corals outside the tank. Just when I think I got them, they show up somewhere else that didn't have them before. From what I can tell they spread with tendrels, but do also spread spores some how. If so, the Fenben may be only way to eradicate them.