I would definitely avoid that site.
There is science behind using a stable oxygen isotope to essentially create "heavy oxygen water," in which many ordinary organisms cannot survive in. But, there's no claim on the website as to which oxygen isotope they are marketing, nor do they have any information about how they are creating or maintaining levels of the isotope.
As they give instruction of using the product as "drops," and clearly label the product as stabilized oxygen, there's a point in which they left the grounds of hiding a trade secret and went straight into boldly lying to mislead potential customers about the product.
There's no way that someone can understand the chemical properties behind stabilized oxygen isotopes and be that confused about bacteria and virus survival rates.
And, simply put, everything has a formula. Their claim that this doesn't have a formula is likely a simple way of avoiding liability by never promising any product whatsoever.
Edit: Note the book about it that is sold on the site is by a man named Gordon Steward. I'm not sure how he is monetarily connected with the product, but it is worth noting, since his book is used throughout the site, that he is a homeopathic doctor. For what that is worth to you.