An employee at or local public aquarium told me 2 years ago that they use CP for disease management. I have been using ever since. I use 24/7 on my quarantine and hospital tanks. I once did a 5 month test on one of my FOWLR display tanks and had no ill effect on tangs, angelfishes, clownfishes, dottybacks and a coris wrasse.
I collect a lot of clownfishes and sometimes they come in it ich, velvet or brook. I use to use copper, but by the time I discover they have brook... it's too late and they end up dying. Copper has no effect on brook and it is a fast destructive disease.
Now I treat all fishes in quarantine with CP for 3 months... whether there is any signs or disease or not.