1 fish, 2 fish, dead fish!

[fishoholic]

The biggest thing I found with QT tanks (I've lost a few fish to ammonia spikes in QT tanks in the past when I thought doing large weekly water changes was good enough) was that you have to do a 40 to 50% water change every 2-3 days. Which BTW really sucks when you have a 110g QT tank running. I used more salt in the 2 months of QT'ing my fish (when they had marine velvet) then I usually use in about 5 months. However it was the only way I found I could keep the ammonia and nitrite levels in check.

I agree it is best to bring salinity down slowly but it is very important to raise the salinity at a very slow rate. When you're ready it should take about 2 weeks to slowly raise the salinity back up.