Hi TXreefer,
thanks a lot for your comments. With all the stuff on this board about high definition, I'm almost embarassed to own up to the fact that I'm still using a 6-year old standard definition system! Since you ask, here goes: USVH housing (all electronic controls, great simple housing with no penetrating controls, but when the owner of the business retired, USVH closed down too), UR-pro red filter for all shots, Sony 0.7x wide angle lens inside the housing directly on the front of the camera, a couple of mm away from the inside of the flat port, which is made out of perspex. Camera - Sony PDX 10P, 3-chip miniDV, which first hit the market in 2004 I think. The pixel density is so low (compared with my Sony HC9, e.g., which has just one 1/3" sensor for the many more pixels required for HD) that it's possible to white balance manually even at around 30m/100 ft (in the tropics at least). The clip you saw was taken at around 20m, about 7-7.30 am. I re-white balance every couple of metres or so, as I find that if I get the colours right in the camera it's usually better than any grading I might be tempted to do with Vegas afterwards. If the Sony NEX5n turns out to be good for video underwater then maybe I'll bite the HD bullet...
Matthew