A few time ago it was uploaded in the channel Dan Hiteshew, the video “I’ve Been Wrong About pH For Years”.
As pubished in the youtube page by Dan Hiteshew: “Patreon: https://www.patreon.com/danielhiteshew
All the years I’ve been keeping fish, I’ve believed that pure water has a pH of 6.4 only to find out that it is in fact pH neutral. it only becomes acidic once atmospheric gasses, such as CO2 dissolve into it.”
You can check the video below: