Not to argue about dosing water, but fluoride has no value ingested and is poisonous at low doses. It's best to moderate your arguments against the anti-fluoride mob or you're too easily dismissed yourself.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956646/

> Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed.

https://en.wikipedia.org/wiki/Fluoride_toxicity