I used a big flat brush for this. Took around 2 h and was in between to snorkeling-sessions. The place was amazing, a small cove on the right and a quite deep spot in the middle. There were sealions swimming around, turtles and I even saw 2 rays! Not to speak of all the little and big fish, crabs, lizards, blue-footed-boobies and what have you.
This is my blog.
I will share information about workflow, my insights into image-making or just general thoughts and rants about being an artist.