Working with ideas for water surfaces from below. Here we have the old Caustic Water image shared by Kadri years ago, that has been edited to be a seamless texture (I don't think I can share due to license agreement of the original file).
I am using a 2D cloud setup with the image map, at the same location as a transparent glass setup using the same image map. This allows reflections of the actual displaced water caustics. I added debris to the water, which are plainly visible without water depth cloud, but for some reason the water depth completely masks out the water debris, and I'm not sure why. Even if lit by ambience.
I am trying to think of up a way to procedural do all this but the PFs I came up with just didn't even look right so I never tried. Addition I want to add some dark "Masking" to create a surface falloff, as underwater, due to actual wave/water displacement a lot of shadows will be created over light being let through.
Made a Sea Bass card pop just to add a little something. That I can share (includes card TGC):
https://drive.google.com/open?id=1-EvjOaQlNBIBV8TuMkKpgdSiowPX0jGC