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 Camera Floods: Avoiding the High Water Mark

No subject scares underwater photographers more than having an expensive housed camera turn into an aquarium. Even a bit of water can turn electronics into a corroded mess.

Here are a few general tips on maintenance that should help you avoid finding Nemo in your housing