Quarantining corals can sometimes take up to a couple weeks, depending on where you get the coral from, and what you find on it that should not be there. It is also an ideal place to begin their acclimation to synthetic salts, artificial lighting, etc. Try to mimic your reef tank as much as possible - including lighting if you can afford it.
Realistically, people will use some sort of PC lights or something cheap to at least provide some light for their QT rather than go all out on halides, etc. This will be OK too in most cases for a short duration. When its ready to move your coral over to your main tank, be sure to start them off low in the tank and over time bring them to the spot where they will grow and be happy. This helps reduce light stress from sudden change.