This is the idea I have for the vivarium that I would like to build in my 40 gallon breeder. The tank is 36" long, 16" tall, and 18" front to back. I will need to have at least 3" of water in the tank to keep the pump submerged.
Firstly, I plan to have a false bottom that is about 6" tall in the back right corner and slope it to 5" in the front left corner. I will use the eggcrate to form a 3 sided background in the back right corner to support the GreatStuff foam background, leaving the back right corner acessable for the pump (the black square) to be removed/adjusted.
There will be a waterfall in the back right corner using pieces of slate, cork bark, and river rocks, that will fall into a shallow pool at the base. To make this pool, I will use greatstuff to build a mount the size and shape I want the pool, then once it is hardened, carve out a depression in the center, leaving a wall of greatstuff foam around the edges to hold the water in place. I will then coat the greatstuff with scilicone, and then sprinkle the wet scilicone with pebbles and sand for a natural look.
From the pool, the water will follow a small stream diagonally across the tank towards the front left corner. The stream will be made in the same way as the pool, creating a long strip of greatstuff foam and then carving a channel into it for the water, coating with scilicone, and sprinkling with sand and pebbles.
The false bottom will have the front left corner cut off to allow a drop and a second small waterfall made from a piece of slate. This lower portion will be filled with gravel that will be slightly deeper than the water table, except for directly under the waterfall where I will scoop out an area that is lower to allow a small pool. The front edges of the false bottom on either side of the small waterfall will be hidden with greatstuff foam and coated with scilicone, sand, and pebbles.
The "wall" of foam around the upper pool and the stream will also create a barrier to hopefully keep substrate out of the water. I will slope the substrate so that it is deeper in the back and against the background, and level with the top of the foam walls along the river.
When I can no more stir my soul to move, and life is but the ashes of a fire
When I can but remember that my heart once used to live and love, long and aspire
Oh, be thou then the first, the one thou art, be thou the calling, before all answering love
And in me wake hope, fear, boundless desire.