Quick update! I've now added about 3/4 of the directed amount of copper to the QT. All fish are eating and still acting normal

except one fish :/ my Sailfin tang seems to be getting worse (more ich present). He is still swimming and eating, I just see more spots then when I started the treatment. Hmmmm? Is that supposed to happen? Or something else wrong ? Everyone else is getting better and doing great as fas as I can see and tell. Shall I just wait and see what happens ? I see another dose of copper this morning. I'm still under the directed amount due to I don't have a copper test kit yet. Haven't had time to get one