There is definitely difference of opinion here. You'll have to decide.
I say put it directly into your tank. Deal with the hitchhikers later, but get that rock into the healthiest situation as possible as soon as possible.
If a hitchhiker is a serious problem, you can always remove the rock later and deal with. Right now, that rock has been out of water for long enough and it needs immediate maximum life-support...FAST.
The problem I have with qt
is that they are usually set up at the last minute and don't have established bio filtration. Starting the qt
with some tank water isn't enough. Freshly mixed salt water is no better. A fresh qt
is basically a fresh tank...unable to support life until it cycles.
If you had created the qt
over a month ago, cycled it completely so it was ready to accept the rock that's different...but it doesn't sound like you did that.