So, after I had finished carving I applied my first coat. I used white Drylok as the base (4 cups) and added Quikrete dyes (1/4 cup red and 1/16 cup brown). I let this dry for a few days to makes sure it was good to go. I used all of the extra left over from the front to coat the side and back twice to ensure it was nice and strong. I wouldn't add any more than that for fear of stretching the dimensions.
The next coat once again used the Drylok as a base (4 cups), to which I added brown Quikrete dye (1/8 cup brown). I covered up most of the red, purposely skipping over the deep crevasses so they would retain the red.
For the third coat I used what was left of the brown (About 2 1/2 cups) and added Brown (About 3/16 or so). It wasn't dark enough, but my father told me that if I were to add too much of the pigment it would destroy the Drylok, so I decided to add Acrylic into the mix. I used Mars Black (About 2 1/2-3 teaspoons). At this point I felt it was sufficiently dark enough, so I applied it, being sure to skip over even the more shallow crevasses.
Once that dried, I moved on to the last coat. I used a similar mix to the second coat, but added some yellow acrylic until I had the sandy color I was looking for. Then, using a natural sponge, I would take a little bit of the paint, dab it off on a paper plate, then lightly dab it onto the background. This is what really made it look amazing. So, I'll post some pictures of where I'm at right now!
So, here's a full background shot, including the plumbing.

Here's some details, flash on and off, and different spots.


I had to cut it into pieces (Pre-painting) to get it to fit. I cut the big piece I had to cut in half at an angle to make it easier to blend.

Here's the back and sides.

Here's the spraybar.


And here's the intake to the SunSun Canister Filter.


