Ich in quarantine after 30 days in copper

[Chris' Reef]

I was about a week from starting to put my fish back in the DT following a 76 day fallow period for ich. I treated my fish with Copper Power for 30 days at 1.85ppm, verified daily with a Hanna checker.
Three weeks ago when the 30 day period at full theraputic levels ended I did several large water changes and began running Cuprisorb to remove most of the copper.
Today while doing routine maintenance I noticed a few spots that appear to be ich on my blue hippo tang. There has been no cross contamination and nothing new added to the quarantine tank since I started treatment. Is it possible I've run into a copper resistant strain or a strain that encysts longer than 30 days and therefore survived the copper treatment?
What steps should I take next? More copper and transfer to clean tank? TTM? I'm really tired of fighting ich and want to ensure I eliminate it this time.

 

[HotRocks]

I was about a week from starting to put my fish back in the DT following a 76 day fallow period for ich. I treated my fish with Copper Power for 30 days at 1.85ppm, verified daily with a Hanna checker.
Three weeks ago when the 30 day period at full theraputic levels ended I did several large water changes and began running Cuprisorb to remove most of the copper.
Today while doing routine maintenance I noticed a few spots that appear to be ich on my blue hippo tang. There has been no cross contamination and nothing new added to the quarantine tank since I started treatment. Is it possible I've run into a copper resistant strain or a strain that encysts longer than 30 days and therefore survived the copper treatment?
What steps should I take next? More copper and transfer to clean tank? TTM? I'm really tired of fighting ich and want to ensure I eliminate it this time.

Can you upload pics?

Hippos can be hard to judge. Since they love to wedge themselves places. Hopefully it's not ich.

 

[Chris' Reef]

I'll try to get some pics, but it's difficult to see in person. I have been observing the tank for a little bit and saw my sailfin (no visible spots yet) flash a few times, so pretty sure it's ich. Ugh!!!