Changing the sun color is one way to change sunlight intensity. You can also change the "Light Intensity" slider in the "Light" tab of the "Atmosphere Editor". Be sure the checkbox is set to "Sun only", or it will affect all light sources.

When changing sunlight color, to stay "white", just keep sunlight colors pure neutral (i.e. equal values of Red, Green and Blue). Pure white = full intensity, gray = some intensity, pure black = sun off.

I think your caustics look good - could be a bit brighter (lower sun intensity, as you already said). Maybe the water looks too clear? Hard to say without background objects.

_ jc...'Art Head Start' e-book
.......'Art Head Start.com site Digital Art skills. Free lighting chapter, tutes, Vue models, tex pix.