Ozone is O3
Ozone is created when electrical energy breaks apart a oxygen molecule (O2) into two single O1 atoms. The free O1 atoms unite with other O2 molecules to form O3 (Ozone).
Ozone is an unstable molecule. The third oxygen atom combines with inorganic and organic molecules to destroy or change them through a process called oxidation.
In a spa, ozone will oxidize organic molecules such as: viruses, fungi, bacteria, yeast, oils, chloramines, etc
The Spa still needs either some chlorine or bromine for this oxidation process to work
Ozone is great for maintaining your spa water