My 55 and my 40 have ich. I called my local aquarium store and they suggested that I use seachem's ployguard. I used it and it seems weak. I have ich-x and want to change over to that. However, seachem has that sulfathiazone in it. I says on the ich-x bottle not to use with other meds especially those with sulfa. I treated my 40 first and lost 3 angelfish and I was warned that the med would turn my water blue, it never did. Somehow I cross-contaminated my 55. My favorite fish are in that 55. They clearly have ich and I've treated with salt and an airstone and temperature raise. Should I change over to ich-x and how would I do that safely. Would i do a massive water change after filtering with carbon. Then add more salt and the new meds?