No cement. They sit, and are locked, pretty tight. As I'm sure most everyone here knows: It took 3 hours one day, 2 hours the next, and 2 more hours after that to get it how I wanted it.
As far as the substrate goes: I read a few books, read a lot of posts on the forum, and asked a lot of questions at my lfs
. But I am just a rookie in this avenue of the hobby. I'm told it is not cc
. It is aragonite based Fiji live sand. One third live, two thirds dry.
Thanks for the comments. All comments are welcome as that is the best way to learn.