You're about a half a stop to the dark side. Your reef is going to have some blown areas. Unavoidable in most fts. Use your Levels adjustments, particularly the mid-range, and the shadow highlight tool to open up the shadows and bring down the highlights. This image is pretty close. Your water appears to have a lot of bubbles/debris in it, which is refracting light and altering sharpness. Shoot a bracket, one stop overexposed, according to your meter; one shot that is what your meter says is the proper exposure; and one that is one stop underexposed. Then choose the best of the bunch. Make sure your flow is off and the water relatively debris free. Shoot in RAW. If you want, send me the RAW files and I'll help you with the PS part of it.
Gary