P.S. and PSA:
There is a lot of concern from different people and groups about antibiotics use and the spread of antibiotic resistant bacteria. That is a valid concern, but something that is totally untested in an aquarium setting. Nobody can tell you what the real risk is because no one has a clue. Still...
Be on the safe side. When treating your tank with ciprofloxacin, you won't be doing much with the tank. No water changes or anything. When the treatment is done, you may want to do a water change. Best practice would be to dump bleach into your waste water before dumping it in the sink/toilet. Try to put about 10% of the total volume in bleach into the water bucket/brute can and let it sit for at least half an hour. This will kill any bacteria that may or may not have developed resistance to ciprofloxacin during treatment. Also try to limit your hands in the tank or wear gloves that go up high enough to not get water all over you, especially if you have an open would--it would not be fun for you to get an antibiotic resistant bacterial infection--I don't know the likelihood of that ever happening, but if you prefer safe than sorry.