You can use bio spira and a sponge air filter. I have had then running in under 2 days before I put fish in them. If you have a little more time then use bio spira and put in a little ammonia concentrate to help build up the bacteria you just introduced. I never use anything from my tank, I just put in new saltwater, at 1.020 salanity and add bio spira, and use a sponge filter.
I would wait at least a week or 2 before starting a QT as anything can happen in a tank cycle, my DT was cycled in under 2 weeks, others have takin as long as 6 weeks.