I have a single fish in therapeutic copper. Had him for a couple weeks then slowly raised the levels over 6 days with copperpower to around 2.0 with HC. I have an opportunity where I might be picking up some fish from another reefer buy am unsure of they could just go straight into the copper at 2.0 or if I would have to lower it first and raise it again. It's only been therapeutic for a few days.