Yes, to a quarantine tank after a 1-3 minute FW bath, then treat the original tank for ich, reefkeeping.com has an article on treating tanks without meds, just google "treating marine ich. I am not a SW keeper so can't give you any help here.
Just cleared up the ick in my salt 150 tank now my niger trigger has one completly clouded eye ( not popeyed) and my pinktail trigger looks like its starting with him. Some good direction would be good. Thanks