[Norseman]

In children's terms? First you push that little knob on the side and then...

Ah... what camera do you have? Canon or Olympus?

In short you want to find the whitebalance button. There should be one provided the camera is a medium advanced one.

At depth, say 20 meters, point the camera at something white, so that most of the screen is covered. Then click on what the camera will have you clicking.
What happens is that the camera "boosts" the red since it can't find much red when you point the camera at something white.

Kyrre