Out of ideas.

[fsjman]

add garlic to the tank and turn your heat up to about 81 or so I have two yellow, sailfin ,regal,miki,and brown tang in my 150 and had a ich outbreak at the first. I poured a full bottle of garlic in the tank and turned up the heat and have not had a sign of ich ever since .... ich hate the garlic . also my tank stunk of garlic till my first water change but they all lived also buy some Ocean Nutrition seaweed select with garlic added the tangs I have liked the brown algae the best Good luck

[Wayne]

Does a freshwater dip get rid of ich? Do you have a quarantine tank?

I read on http://reefkeeping.com/issues/2009-04/newbie/index.php
that a salinity of 1.009 was needed for combating ich. Definatly shouldn't do this in your display tank though. After about 48hrs of 1.009 slowly raise it back up to normal salinity and just watch them for signs of ick for about a month.