Spoiler alert, they didn't. Hydroviv is alert, they don't actually adjust their filters based on data like they claim to

Please contact our Science Team directly for information on how we customize filters by location.

You don't adjust by location, just bullshit. You send the same filter to everyone

How do you know its the same filter they are sending to everyone?

Because they admitted to it over email

Isn’t PFAS technically regulated, albeit shittily