Attached Link: http://skytimelapse.com/503.mov

Hi all, I've been playing with cloud animations, and the only thing I can't seem to solve is the semitransparent cloud layers. I minimised it in this clip below but you can still tell: http://skytimelapse.com/503.mov Does anyone know how to make the clouds totally opaque? I've played with the cloud thickness and everything but cant seem to get it just right.