quarantine tank

is a 10g enough? or is going to pose problems because it's small and
unstable?
I got a sailfin tang that's developing ich, so I dipped it in my roommate's
f/w tank for 10s, it seems to have slowed it down, but I need to medicate
it..should I just have a sick tank with some copper in it? Will that be
enough?

I have a 10g set up that I was going to make into a f/w plant tank, but i'll
change it to a s/w sick tank if it'd be benificial to have...it's got an
aquaclear mini filter, a heater, and an incandescent canopy...shouldn't have
lights if I'm trying to heal them i guess...I would just medicate my display
tank but I've got live rock in it..can't afford to kill it.

TIA,
John