Is it OK to use dirt in a nano shrimp tank? I'm assuming this shouldn't be an issue. As I understand it, 1" of dirt with a 1.5" sand cap should work nicely. Can the layers for each be deeper without running into issues with gas pockets? When planting rooted plants, I'm assuming you plant into the sand and let the roots work their way into the dirt on their own, correct? Thanks in advance.