What is Reddit's opinion of Apnea training?

From 3.5 billion Reddit comments

For starters I recommend the Apnea Trainer app for home use.

https://play.google.com/store/apps/details?id=ru.megazlo.apnea

Then creep some of the freediving forums when you google for them. A lot of these forums have great discussions on equalization.

When I did my freediving training Course, I was given a book called "Manual of Freediving" by Umberto Pellizari. It's got a very colourful Italian style to the writing that seems cheesy to me but it goes through all of the basics you need to know or train to be a good and safe freediver.

https://play.google.com/store/apps/details?id=ru.megazlo.apnea - hooks up to an o2 sensor and graphs/records all your sessions.