Something else to remember (isn't there always something else to remember in this hobby?) for the QT is that any thing you put in there for the fish to hide in will take up copper, whether it be coral rock or PVC. PVC is much less of a problem and easily disposed of after QT is done. Copper will bind with the calcium carbide in rock and significantly affect your therapeutic levels. Additionally, if you have a pH drop for whatever reason it will come out into suspension in the water column again and drive your Copper levels sky high (been there, done that, 45 years ago). PVC is the best option but make sure you have a good copper test kit that is oriented to the type of copper (chelated vs non-chelated) you are using. I'd also consider going hypo-saline in the QT once you have the fish settled in. You can drop the saline levels over a few days with additional RO/DI water to about 1.09-1.010d for a couple of weeks and then start bringing it back up to normal levels. This last comment may start a s**tstorm of controversy, but I have used hypo to good results in the past, especially if gill infestation is an issue, as it is easier for a fish to respire in less dense water and the parasites don't seem to do well in a more brackish environment.