I have always seen people using clay flower pot in QT, but never dared to try since I don't know much about how or if it will react negatively in saltwater. Please share with your experiences. Thanks.
You mentioned it's for a QT...if you're going to use medication you are better off with PVC than clay pots. The clay will potentially uptake the medication you're dosing. This will initially weaken the concentration of the meds and then eventually leach it back into the water when you're trying to drop the levels of meds. If your QT is intended to just be for observation and food training then I'd say clay is all good.
+1 to what Omar said. Clay pots do have a good surface though and act like live rock. U can use it if ur not medicating but PVC will be better for meds