melafix/carbon

I'd do both. First large water changes to get most of it out, then add new carbon. it should remove all the traces of it in a few days.

What kind of fish do you have in your tank? If any of them are labyrinth type fishes i.e. gouramies, bettas, etc. you might want to stop using it immediantly. The reason being is that I read that the active ingredient (melaleuca) could actually cause irritation to the lungs and possibly death. I have also heard of people using the product and having no problems at all. Everybody has different experiences. Also Bettafix has this same ingredient and if you look at the directions they want you to put double the dosage than that of melafix. If you calculate it all together you are adding the same amount of melaleuca either way you go. Just thought I'd pass that bit of info. on you.