Well, I have to say that I don't agree with putting any type of medication in a reef tank. The effectiveness of the so-called reef safe meds is really hit and miss. Some people say it works, but more say it does not. Also, the long term effects of any meds on inverts or the overall health of the reef tank is unknown at best.
How are your fish and tank doing with this medication?
I would really recommend that you setup a QT for future use in quarantining new fish before they go into your reef tank. There is just no way to avoid introducing fish diseases to your tank without doing this.
As for garlic, I find that using fresh garlic cloves works best. In a container crush the garlic until you extract the garlic juice then mix in your fish food [not flake foods]. Let the food sit covered in the refridge. for at least 1/2 hr then offer it up to your fish [Not the garlic but the soaked food].