Advertising & transparency
How we fund this site — in full.
Affiliate links
We link to filters, test kits, and devices via affiliate programs (e. g. Amazon Associates). Buy through one of those links and we receive a small commission. You pay nothing extra.
Affiliate links are marked in-text (e. g. "ad link" or *).
Does advertising influence our recommendations?
No. We link to products that, based on our research and (where feasible) own testing, make sense. We do not accept payment for positive reviews. Bad filters are called bad.
Display advertising (Google AdSense)
Currently no display advertising. Once activated, you'll get a separate consent prompt with opt-in for personalized ads.
What we don't do
- Sponsored posts for individual filter manufacturers
- Hidden, unmarked advertising
- Health-related claims without sources
- Selling personal data