When I'm spearfishing, I don't think of the video since the camera is on my mask, just let it run
Hopefully get some sand in there somewhere, sometimes an amberjack swimming by is a good white reference. Have you tried green water filters?
https://youtu.be/ishcb_qGybI
I prefer the color editing sometimes to white balance, PD has stand alone color editing that integrates with editing. You might find this interesting
https://youtu.be/F2kEhtVOCnQ
Lastly, I just noticed my clumsy fingers entered 6K Youtube views for the orig Red Carpet Anemone Video but it is
60K+ views