I don't recommend keeping a tank running long term with copper and or meds.
I do recommend running a fully cycled (about 30 days or so) QT with the following in the QT to maintain good water quality. I seldom have to do water changes during QT.
1. HOB filter with a foam pad and a mesh bag with either Seachem Matrix or Fluval BioMax that has either been soaking in my DT sump for at least 30 days or soak them with BioSpira, etc. over night and then add the liquid to the QT.
2. A bubble filter with the foam pad treated the same as above.
3. A small powerhead aimed up at the surface so it's actively rippling the water's surface to increase O2 in the water column.
4. A Seachem Ammonia Alert badge, just to keep an eye on things.
5. heater
6. QT tank with end and back wall painted black or dk. blue to keep the fish calm.
7. Pieces of PVC and plastic aquarium plants to keep the fish calm.
8. Prime ready just in case (but this is only with chelated coppers like Copper Power or Coppersafe.
Antibiotics: NFG powder for tangs, angels, butterflies, especially; for the rest, Spectrogram
Copper: Copper Power is the most consistent and reliable. Hanna Copper Checker.