Other contributors have said "Hot tub chemicals?" is the same question as "What chemicals do you put in your hot tub?" If you believe that these are not asking the same thing and should be answered differently, click here
Chemicals used in hot tubs include Bromine or chlorine. Chlorine comes in granulated forms or a liquid. Another chemical used in hot tubs is sodium bromide.
if you want to however, you may have some tragic accident for example death. this all depends on the longitude and latitude of the balcony and hot tub... i suggest you might want to use a tape...
"Some of the chemicals that are needed for a hot tub are chlorine, bromine, biguanide, ozone and mineral spa care. You also need to change the water every 60 to 90 days."