Film?

[Brewski]

If you have no strobe, and will be relying on your HID for illumination you may consider Black and White film. Since the color temp of the HID will affect the overall color of the photo. Also the HID will most likely illuminate a hot spot in the center of the frame and not light the subject area evenly without some sort of diffuser.

 

[wildoceanphoto-dotcom]

Keep in mind that the "grain" of the film is more pronounced in your negatives and prints when you go with a higher ISO film. In general, you only want to go with higher ISO film if you are in lower light situations. I'd suggest starting with a 100, and if you find yourself needing more speed, go to 200, then 400, etc. I second the recommendation above for Fuji film for color saturation - Velvia has traditionally been a popular choice for underwater photographers.

Hope that helps!