new QT water or Re-use?

[Gregs]

Ive set up my 220g fowlr and now im in the proccess of stocking up fish. I have setup two 33g QT's for this and was wondering if there is a method to shock or treat the water somehow to kill anything left in the water and just reuse it for the next fish?
wondering if a heavy copperdose for a few days would suffice then clear it out with carbon?? temperature drops/raise? cleaning out the tanks between fish and mixing up a new batch of water is a PITA so im wondering what you folk all do.
Thnx