research on how to film water close ups

A video I watched that showed how to film cool underwater shots 

This thought me how to take some really cool shots that look absolutely crazy. I would love to use some shots like this in my documentary but I do not know how realistic this is as it requires quite a lot of equipment.

This is some footage of me having a go at filming water in slow motion.

This is me experimenting  and filming water for the first time