I completely get the benefits of using a quarantine tank before adding new fish to an established tank. I've made the mistake in the past of skipping this step, and I don't want to do it again. However, I'm not in the habit of adding new fish frequently, so I'm wondering...
a) Is a quarantine tank just an empty tank that you keep running (filter, etc.) in case you need it at some point?
b) If the above answer is "yes" then how do you keep the tank healthy and cycled with no fish in it? If the above answer is "no" then how do you quickly set up a quarantine tank when you need it without going through the whole cycling process?
I'd rather not have to buy a whole small tank set up just to have on hand and ready for the infrequent times I might introduce new fish to my tank.