The cocoa should sit on top of the krausen it's very powdery and light. Once fermentation settles down it should settle out. It looks good!!!! I bet it smells fantastic!!
My brewing buddy and I have done a grapefruit (and other citrus) IPA. It's one of our favorite recipes. We do a steep at the end of the boil. Then we rack into a secondary and use the rinds for a week.
It's amazing!! And yes for 5 gallons two red grapefruit peels is enough to flavor the batch...