I use it to just incase I don't have flatworms but I'm paranoid so I use it anyways I'm on my secound bottle duke used it and he was infested he bought a few wrasses flow off the corals every other day and used the flatworm stop 3 months later and his tank looks great lost a few tiny frags but I belive that's all I would say the stuff works well time will tell but it looks like there def gone he's been basting the corals and mornings coming off