If you plan to use the 3-Step bromine method, then an ozonator is unnecessary. You'll be using bleach or dichlor to activate bromine from the bromide bank and a floater with brominating tablets to try to keep the level consistent. Ozone would only really be necessary if you were attempting to use that to create your sanitizing bromine and keep it a certain level. Most hot tub ozone generators are junk and don't last more than a year or so. Since an owner has no way of knowing if the ozonator is producing anything, they usually do fine without it and never replace them.
Just be warned that you need to do a lot of testing up from to determine how your hot responds to different conditions and how your bromine gets used up. So test frequently at first so that you can track you water chemistry accurately. Also, brominating tablets, like some forms of solid chlorine, are acidic and will lower both pH and TA over time. So make sure you are testing those values and don't be surprised if you need to add borax to increase pH or baking soda to increase TA (and pH if you add it with the air blower going).
