@aaron23 if the fish stops eating stop adding the meds (whether its copper or any other) I would remain at that level for 24 hours and if the fish still does not eat I would do a water change without adding copper to lower the level. I would try feeding at that concentration for a few days and if it starts eating I would resume adding copper and if doesn't start eating I would lower the copper levels again. But, someone like @melypr1985 (on vacation so may not reply) and @Humblefish would have more experience.
As far as turning the QT into a DT I would not use that water regardless of what the copper levels read. I would thoroughly clean with vinegar and bleach and allow ample dry time before trying to. But personally I would keep it as a QT/hospital tank.
As far as turning the QT into a DT I would not use that water regardless of what the copper levels read. I would thoroughly clean with vinegar and bleach and allow ample dry time before trying to. But personally I would keep it as a QT/hospital tank.