IMO, the best and safest way to treat ick is with a hospital/quarentine tank and hypo salinity, it is the safest for the fish and being as you use another tank, it is completely safe for the inverts left in the main tank
there are many (supposedly, some are safe some aren't)reef safe cures for ick, but none are nearly as effectiive as copper or hypo, and copper is toxic(even to fish), the only completely reliable and worthy methods are the copper or hypo(both of which should not be done in the main tank with lr or inverts)