Blue Hippo - Ich - Treating with copper

[scherzo]

I have a Hippo Tang in a 15 gallon (It is a juvenile) and am treating it with copper. (It had ich).

Since I setup the tank a week ago ammonia is now going up. (**is a hospital tank.. NOT a DT!**)

How should I handle the water changes and re-dose the copper?

I think I'm about .25ppm for ammonia.

Should I just measure the amount I'm taking out and then re-dose?

I do have a copper test kit but I know that it is sometimes difficult to calculate dosage of the copper using a test kit. Maybe test 1st to get a baseline?

Anyone with experience?

Thanks