Any reason not to have LR in a QT, as long as
the rock is not transfered from tank to tank?
Not at all. As long as you don't move that LR
back into your main tank. This is especially important if you use copper meds.
Will meds kill off the LR?
Depends on what meds you use. Copper meds will kill off any inverts living in the LR
, but should not effect the biological bacteria unless the copper dose is extremely high. Most anti-bacterial medication *WILL* kill off any beneficial biological bacteria on the LR
and it will then become dead base rock.