A quarantine tank shouldn't have live rock in it. Just a heater, small powerhead pointed at the surface for good gas exchange, and some pieces of PVC for them to hide in. You can use black or white PVC, just the fittings or some pieces of pipe. Use at least 50% water from an established tank to fill the QT, and add a seasoned filter pad from the established tank as well. I like to use a SeaChem Ammonia Alert which works very well and lasts a year. I use AmQuel to detoxify ammonia when needed. Most ammonia test kits are not compatible with ammonia detoxifiers, but the Ammonia Alert is. You don't need a light on it, but you should have a lid of some sort because new and sick fish startle easily and are prone to jumping out.
For hyposalinity you HAVE TO use a refractometer to measure salinity as you need to be very accurate. Here is an ok link the hypo...wish I could find a better one:
http://www.aquariacentral.com/forums...o-Hyposalinity