I had done some preliminary bench testing on peroxide before I retired. The info is here:Jay I had a question on this if you see it.
I might have a similar problem but I do not have copper in my tank. I was wondering if I reset my tank if I dose it with high levels of Hydrogen Peroxide. I believe that should kill everything, Parasites and Good/Bad Bacteria. I believe the peroxide will cycle out of the system, I then would do a 50 percent water change and re-cycle the tank. I have dry rock and crushed sand bottom. This way seems faster and less work not to mention less water waste. What are you thoughts, would this work?
Hydrogen Peroxide Bench-testing
Bench testing of the effects of hydrogen peroxide in aquariums.
www.reef2reef.com
Peroxide has good and bad points; it does decompose readily into non-toxic constituents, but dosing it is dependent on organic loading of the system, and it is difficult to measure the active dose without using the test strips I mention.
I just never got the the point where I felt I could use peroxide to fully sterilize a system.....
Jay