Balconies, on average, can only hold 40-100 lbs per square foot, depending on their construction. An inflatable hot tub filled with water can weigh between 2700 lbs and 3700 lbs. In other words, placing an inflatable hot tub on a balcony is not a good idea.  With the proper support underneath, you may be able to place an inflatable hot tub on a deck, although many people choose to place their hot tubs on a solid base next to their deck.