There are a few things that determine the amount of color saturation and image clarity in underwater photography: depth, ambient light, and water clarity. Obviously you're not in control of the depth that your subject is at, or the water clarity, but you do have some say in the amount of light.
Underwater Photography Article Center
We went over to the Big Island for a week of “cillaxing” in February. Staying in a condo, we enjoyed several long drives around the island to visit the Volcano National Park, Hilo and the north end...
I managed to get out with Jack’s Diving Locker on one of their limited load trips one day. They did a great job with only 4 divers on a boat made for 8 or 10, for photographers it’s well worth the extra cost.