well i am new to the whole reef set-up my self but i have had a few years in FO
i had a 55g and had a purple and yellow tang and a clown fish. and i was always runing into the purple tang getting ick. its like they like to have it or somthing lol.
well i got tired of moving rocks and trying to catch the little bugger and i stumbled across a fish checher lol i cant remember the name of it, its been a long time ago but i just put dryed sea weed in there and he came to eat and i closed the hatch and put him in a Qtank. then i did i guess what is called a hypo somthing and lowered the salt to 1.009 over a few weeks and then slowey move it back up to 1.025 took about 5-6weeks then he was fine. but if u have the little buggers in your mian tank and a fish is able to host the ick u wont ever get rid of it. its best to qtank them all and let your tank set for 5-6 weeks to give the ick's life span to die off.
i know i am not as good as some of these other guys but it helped me a bunch of times. kinda a pain in the butt, but these fish cost to much to lose if u know what i mean.
o by the way then i bough a UV
lite and i sware by them if u do it right. other may not agree. good luck and i hope u get your problem under control