I'm on the third floor with several tanks (55,75,10,29,5,6.) I'm kind of scared about setting up my 75G and are looking at renter's insurance. Some of my flooring had already sagged without help from the tank. :o
One the UPS issue, I would say it's a waste of money if you wants it to run for 30 to 45 minutes. By the time you need help from your UPS, the battery is probably long dead. You can try looking into a gas power generator from Home Depot or Lowes.
Look at all those live rocks on the beach at Florida's state park!