Welcome to our forum.
Can you not retro fit a non oem one. ?http://www.ebay.co.uk/itm/A2Z-Ozone-Aquatic-2-Ozone-Generator-Hot-Tub-Spa-Ozonator-AUCWED3-/321255387968?pt=LH_DefaultDomain_0&hash=item4acc503340
As Tman suggested, the tub would of course need to be Ozone ready.Usually indicated with a single small jet in the footwell i believe.
No you can not. Unless, the tub is Ozone ready. Some are but not all.
Any other opinions on the cost / benefit of having an ozonator?