go look at some pictures of water... don't just guess at it! You shouln't need to be asking if this looks realistic... do you honestly feel it is?
use multiple layers of noise so that it breaks up any repetitve noise patterns.
Rendering smamples also need to go up. With regards to showing the dome I understand what farbtopf means but it's better to leave it on rather than showing the picture on black (as it gives you a false impression of the render)
Technical Director - Framestore
Currently working on: Your Highness