I think treating for 7 days has been the most effective for me. Usually when the deflation stops, you'll want to treat for another 2-3 days afterwards. Deflation typically stops about the 4 day mark- give or take a day. Terminating treatment early can result in a dead anemone or a drug resistant pathogen. It is my opinion that "some" wholesalers are running low-level antibiotics in their holding tanks or stopping treatment too early. This is why some anemones do not respond to treatment. It's what we refer to in the hospital as MDRO's. (Multi-Drug Resistant Organisms) Moving on...
Using a 10/g Gallon tank has been the easiest for me. I use a lot of 5/G tanks as well to save saltwater. All you need is a small heater, powerhead, and egg-crate to protect the anemone. Put the anemone on one side and the egg-crate, heater, and powerhead on the other. When you do a water change, suck all the detritus off the bottom of the HT, but do not get close to the Nem. I have sucked up more than I can count and I believe that it resulted in a few deaths. I know, it's that one piece of sand, black pellet, string hanging around the column, etc..that will bug you to death. Trust me, just let it be unless you know you can get it easily without causing trauma to the Nem. As far as discarding the water, the light breaks down the antibiotic in the 24 hour period and you can just flush it or pump it down the sink with no ill effects. When you add new water, make sure it's heated, aged at least 24 hrs, and SG matched to previous HT tank water. That's basically it. Any questions, feel free to PM me for help or opinions. Or you can ask JustinKY and Clorox who will be here shortly. They both have experience as well.
One other thing I would like to note:
Bactrim or aka Septra DS works very well too. I recommend treating with that first. Lately, we've used Septra more than Cipro with fantastic results on S. Gigantea and S. Haddoni. Cipro seems to work the best on H. Magnifica's. Septra is made of Sulfamethoxazole 800 mg and Trimethoprim 160 mg. The dose is one pill to every 10/G. However, let it be known that Gigs seem to overdose on Septra after long Treatment times. This is not confirmed, but we think that's what happens. So going forward, it might be a good idea to dose half a pill to 10/G. Good luck!