Rid ich will not erradicate the ich, Get some copper and place all your fish back in your 30g tank and use it as a hospital tank. Copper is the only tried and truley effective treatment for ich. Check out the articles and forums at Wetwebmedia, Aquarium, Pond, Marine and Freshwater Fish, reef tanks, and Aquatics Information . As far as your really sick fish is concerned, you may want to try a FW dip and act quickly. Take some FW in a bowl, add about 5-10% SW. Adjust the pH with baking soda and adjust the temp as well. Add several drops of methylene blue which aids in oxygen transport in FW. Then aerate the water with an air stone for 20 min. After this you are ready to dip the fish. You need to dip for a minimum of 3 minutes and a max of 5 min. The fish may lay down on its side but dont worry. This will help rid the fish of the parasites on its skin and gills.
If you decide to treat with copper, try seachems cupramine. Its supposed to be a less toxic form of copper and can be removed with charcoal and sea chems cuprisorb resin. You must also use a copper test kit to watch the levels. Too much copper will kill your fish and too little will not kill the ich.
With sea chems copper you must use a sea chem copper test kit. I have used this product with great success.
There's a new all purpose treatment for bacterial, fungal and parasitic disease that I'm using to treat ich in my new Powder Blue Tang in my QT tank. So far so good. Its called LifeGuard SW tablets with Halo sheild. Its very safe for fish and you can use it in your main tank. Its made by Jungle Labs/Instant Ocean/Marineland.
Good Luck. _________ 75g reef with Nova Extreme 8 bulb HO T-5 lighting, refuge, Remora skimmer, DSB, Seio powerheads, Acro's, LPS corals, assorted zoo's & mushrooms, Yellow Tang, Maroon Clown, Blue Cleaner Goby , Cleaner, Fire and Sexy Shrimp, Coco Worm, T.Crocea Clam, Derasa Clam
120g FOWLR, 260w Orbit power compact lights, Remora Pro skimmer, 30g DIY Sump/Refuge, DSB,Seio Power heads, Powder Blue Tang, Purple Tang, Flag Fin Angel, False Eye Puffer, Copperbanded Butterfly and a Moorish Idol  | 
