Prazi-Pro is not a copper-based medication.
I agree with b0bab0ey's suggestion to perform a fresh water dip. It's both diagnostic and palliative for the tang, and may help you save some time on proper diagnosis and treatment.
I've treated my reef tank with Prazi-Pro before with minimal problems. My BTA didn't expand as much during the treatment period, but made it out alive. All corals (I have mainly zoas, softies, and LPS), inverts, and clams did fine. My tubeworms and feather dusters also did well.