I haven't tried ich attack, but I tried ich-x and it was a waste. After a week of using it all my fish were nicely covered in ich. I ended up getting a uv sterilizer and some garlic guard and most of the fish survived from that point on (I think I only had a foxface and some chromis left). I had problems with ich on and off for over a year in my 150, since I put on the uv I haven't had any problems (only run uv when adding new fish). Quarintine is the way to go, but since you already have it a uv might work for cleaning up the tank now. Just an idea, maybe someone with more knowledge on uvs and ich could fill you in more, I just know what has worked for me.