I'll just throw in my opinion based on my somewhat limited experience - I wouldn't ever dose copper into a aquarium that is going to have livestock in it long term ( a non-quarantine tank ).
There are stories all over this forum about strange crashes, livestock dying etc., and once an ICP test is finally sent off, people find out something is leaching copper into their water killing coral/other livestock. It seems like copper can get into the silicone of the tank, live rock like you mentioned, and even plastics from different equipment.
I feel bad saying this but if I were you, I wouldn't use that aquarium or anything in it ( sand/rocks/equipment ) for anything other then quarantine purposes. I'm not super familiar with exactly how much chelated copper would be in that 8.5ml dose, but still, I'm not sure if the carbon would be able to pull every bit of it out. And it would always bug me knowing in the back of my head there may or may not be copper that got absorbed into my liverock or other parts of tank. However, it may be so little of a dose, that running that carbon and doing the WC gets most of it out, i think its up to you whether you find it an acceptable risk or not.
Copper is typically more of a pre-treatment to use on fish before they enter your main display tank. If I remember right, when treating for ich, if it is in your main display tank, the tank should go fallow ( fishless ) for roughly 76 days, to allow for the parasites complete life cycle to be over. That time is cut if you are using a dedicated QT tank and doing frequent water changes during the QT process. You can get allot of useful quarantine info from Humblefish ( a user here on RTR, who has a very helpful website on this the details of QT and using different products to treat a variety of parasites and other fish illnesses).
https://humble.fish. Wish you the best of luck!
