ok,, because they will take advantage of sores like these and make them worse.. Honestly this fish issue isn't your fault Rob. Its not lack of care, its a bacterial disease that got the best of the fish while it was stressed....It happens. I would just keep it Furan 2 and let nature take its course. It may still turn around..
I realize that its easy to tie all the bad experiences together , but its a mistake to do that. The tank cracking was terrible...but unrelated to Discus for instance. Fish keeping can throw you curves. A few years ago I lost a whole tank of wild Rams to lympocyctis...Not a thing I could do.
al