Hi All, I was wondering if anyone could give me tips on creating a mountain-like/hill look in a small 5g tank? I was hoping that it would look like a hill with rocks jutting out. However, I am unsure as to what to use as substrate under the rock? I wanted to use sand, but i am afraid of the sand loosening and the eventual collapse of the scape and of compaction and anaerobic conditions forming under the larger rocks. Is there a technique in forming that kind of scape? I have seen similar ideas used before, but am unsure of how to set it up.