There are ways to boost immunity and keeping your fish in a stress free environment will keep fish happy and healty. Once ich is introduced, I think you need to QT. QT, should be first but if you have it, you need to remove all the fish. A 10 gal
tank is only $9 and a filter is not much more. You could use a rubbermaid as well, you just wonf be able to inspect the fish very easily.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,