You're better off with water changes over carbon. Using massive quantities of carbon can stress your corals out just as much as a million dying flatworms.
Now, given that it's too late to siphon out visible flatworms PRIOR to using the product, here are some guidelines to casualty free Flatworm Exit use:
- moderate carbon use
- frequent, medium (20%ish) water changes
- insane flow
- emptying your skimmer cup every time you walk by the tank
That's about it. As long as you follow those through, you'll be fine
