I'm now back from Tenerife—back at the screen—and, as promised, I'd love to share with you the technique we've learned during our freediving course to stop your diving mask from fogging up.
It's common for diving masks to fog up, especially when they're brand new, and the three-step process below can help you prevent this from happening.
Snorkel or diving masks fog up when water vapor condenses due to a temperature difference between the inside and outside surfaces of the lens.1 "The moisture that collects in the mask has to attach to something, which is typically the residue leftover from the manufacturing process that coats the lens, dir, and oils on the lens from normal use and simple microscopic imperfections on the lens."1 This problem seems to have worsened as manufacturers build new masks with synthetic liquid silicone instead of natural rubber.2
As recommended by our instructor, we ordered the C4 Chanteclair "Cleaner" (green) and "Antifog" (blue) products.
This first step only needs to be done once you first buy your mask, and maybe when you haven't used your mask for several months.
The third step is two spit on the interior of the lens and spread your saliva with your fingers.
You're now ready to dive!
My mask lens didn't fog up once for the entire week.
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