If you are never going to QT all fish, inverts, corals, etc. then get a small pack of live rock from Florida and let it spread the worms, pods, starfish, etc. all over the tank. This diversity can help some fish diseases as they fall off of fish for that part of the lifecycle - the tomonts/tomates will get eaten by many things and/or fail to develop if they land on surface bacteria or algae. This is not eradication, but it helps a lot and is why tanks of the past, before dead/dry phase of the hobby, usually had very little disease after 6-9 months once the fauna spread all over the sand - you remember... the waiting for the tank to mature before buying an expensive fish paradigm?
You can get the live rock and have the diverse fauna while you let the tank sit fallow, or have the fish recover somewhere else.
Wet rock from captivity can, or might not, have that same type of fauna. No way to know without really looking at it. If you don't see tons of mini brittle starfish, pods, lots of different types of worms like spaghetti, bristle, etc. then you might need some fresh rock to seed.
If you do have the tank sit fallow, consider dosing ammonium to get the most biologically available source of nitrogen to your corals. Feeding shrimp and crabs can help too. No corals want to get nitrogen from nitrate. Not all corals can even use nitrate, but those that do convert it back to ammonia/ammonium at a cost of 30-70% more energy needed (nobody knows for sure).