my tank has had ich in it sence i can first remember having one. but i have stayed on top of it and never let it get out of hand. but know i want to add some more delicate fish besides triggers and clowns. i have a tang in my 15g qt and i dont want to put it in my tank so it can "survive." i want whats best for my fish so i am gona let my tank fallow for a little over two months. the reason why i havent done this befor is because 1) i did not have a refractometer, but now i do. 2) my qt is not big enough for all my fish. but i got a second qt tank so i now have enough room to let my tank sit empty for two months. so in one tank i have my tang and clown. i am doing hypo in this tank. both of these fish are doing much better. but how ever in my 10g qt where i keep my humu trigger and purple dottyback, i am doing a copper treatment because they are not as sensitive to copper as a tang. but they have been in copper for three days and their condition has gone from maybe a few spots to covered in ich and constantly scratching. i dont get it i thought copper was the more efective treatment. if someone can explane whats going on that would be great. i fallowed the directions exactly as it said but no good results. do yall think i should do hypo in this tank too? any way all my dt has in it is my coral, hermits, and cleaner shrimp. i was gona let the dt sit empty for two months and an extra week to be shure but if you guys think i should do it longer plese let me know. thanks.