Creating an underwater blue "tint?"
 

Hello! I am working to create an ocean scene with Bifrost's BOSS technology, and I need the camera to move under the waves at one point in the video. I want it to look semi realistic, so I want there to be at least a blue tint to the underwater sections, and maybe a bit of foggyness. I've found some tutorials online, but none really mention designing this from scratch. Can anyone give me a hand with this, or point me in the right direction? Thanks!