Congrats!
I figured you might be planning some
LR additions as you seem to know your stuff, but figured it couldn't hurt to mention it.
210 is more than a third increase over 150, and the stars are likely small, unless you've been informed otherwise. Not sure how big your stars are. Mine seemed a little too fond of wreaking sandbed destruction.
I don't blame you on the water situation, but in a
QT tank the damage is limited, and beats starving your fish. I do not know much about Mandarins, but I believe they are not particularly likely to catch things, and haven't heard of them freaking out over water quality. I do know the major cause of death seems to be starvation, so it seems like a risk I might take, based on my knowledge. Like I said, depends on the quality of your
LFS, and if they even have a pod tank, what the tank is like, not to mention any additional knowledge you might have on them or your fish. I have not researched the fish in depth, so if you feel there is anything they might be sensitive to, don't hesitate to ditch this idea.
Regarding the rock transfer idea: Perhaps.. but I think you need a *right now* solution in addition. I've found it very easy to scrape some
pods off the tank glass and dump them into a bag with a very good survival rate. I'm sure she could donate some with little trouble. I do highly suggest the refugium idea however - mine is a life saver.
I'm also pretty sure some
LR sellers will be happy to send you some copepods with, free of charge.