Just set up my QT heater,filter,light will like to know what if any do I dose the tank to fight diseases. Also what the levels should be.salinity is same as DT already. :google:
try to match the dt levels as closely as possible, not always easiest trick though.
i normally do a waterchange and fill my qt with water from that change.
as for treating tank for qt its just like most things in hobby, matter of preference. some have a medicine regimen they use, which requires more water changes. they prefer this method to treat anything that "may" be on fish and this way they are comfortable putting fish in dt
others simply watch the fish in qt make sure it is behaving normally, eating well and not displaying signs of distress.
i recently setup a tank to treat a clown with bifuran. this required a daily water change. the clown was in a normal 10g tank and i did roughly 8g water changes a day for 8 days. the clown is now in the 10g and doing well without medication. it appears the infections (dark colored spot on ribcage area/side) has just about cleared up. i will probly leave in for another week and make sure it continues to eat well and act normal. there are several qt threads on this forum, find one you like or agree with and make it work for you