How many of the fish are affected?
Ick is a pita. All kinds of treatments you can try but most require that all fish are removed from the reef for 6 weeks so the parasite doesn't find a host to keep it going.
I q-tanked a
royal gramma that had ick, treated it successfully and put it back in my tank. It has ick again (probably a result of the major move I just made). None of the other fish have ever been affected. Very frustrating.
I tried garlic, but it didn't work for me. I'm trying a med now that I put in the food - it's supposed to mess up the DNA of the ick so it can't reproduce. Since it doesn't kill the ick on the fish I haven't seen any results so far. I'll let you know if it works.
Good luck. Sometimes the ick goes away by itself if your tank is sable and in good shape.