Ok, first the questions:
1. Yes, these are all smaller growing plants. All are blooming size, except for a seedling which I stuck in there this morning (a Porrovallia Phil Jesup). Oh, and the Tolumnia is NBS, not BS. Oh, and the Macodes is a small start. So most are BS.
2. No fan involved. The top of the aquarium is open, except for where the fluorescent lights are. So hopefully that'll give enough circulation.
3. Not sure about the mold and algae. My hope is that the constant filtering and recirculation from the aquarium pump will keep out the algae, and that the open top will keep out the mold, but, as this is my first attempt, I'm not really sure what problems I'll run into.
4. Oh, and the dimensions are 12 1/2" deep x 30" long x 12 3/4" tall.
Ok, now on to the method of construction.
First off, I stole most of the construction method from this very nice webpage:
http://www.blackjungle.com/gallery/talltank/page1.html
What I did was as follows:
1. Get a bunch of rocks. Place them in the tank. This will form the basic mechanical structure, and the . . . well, the rocks. I wanted to use rocks in order to create a certain kind of scene. Cypress wood, as in the link above, would work as well if not better.
2. Spray a bunch of that expanding insulation foam stuff in there. This glues the rocks in place, and is the basis for the "ground" in the terrarium. I took care to ensure that none of it ended up being pressed up against the front of the terrarium by using rocks as a facade. It took me two cans of foam. Once you start using a can, you need to use all of it, as it will seal itself up within 2 hours. If you're doing a water feature, be sure to leave enough room for a pump or an uptake tube. The pump I used hangs on the edge of the tank, pouring over the side onto the big rock on the right, forming the waterfall. Its intake tube is in the open space behind that rock.
3. Once the foam has set, cut it into shape using a serrated knife.
4. Coat the foam with silicone caulk. Use a dark color. It took me about 1 1/2 tubes of caulk
5. While the caulk is still wet, press washed and dried coconut coir onto the caulk. This will make it look like actual dirt, or at least pretty close. You must wash the coir pretty well first to remove salts which are introduced through the manufacturing process.
6. Once the caulk has dried, vacuum up the excess coir.
7. Plant the terrarium. I used five methods for situating plants, and I plan to use a sixth for a plant I haven't installed yet.:
. a. Attach plant to a coir/foam wall, using a long staple or something similar. I used this for plants with small root systems, including mat-forming plants (moss, Mediocalcar decoratum), and small epiphytes (Tolumnia, Chamaeangis)
. b. Place plant on surface and pile coir, peat moss, or sphagnum moss around the roots. I used this method for terrestrial plants with short root systems, or for other plants in places where I had room to build up a bit.
. c. Cut a hole into the coir/foam "floor" (or in my case "bank"), and place the plant in as if in a pot. This provides for more root space. I had to take care to ensure that the hole I cut did not go below the water level, but that it had a hole in the bottom that did go down to the water, in order to provide some drainage. This was a little tricky.
. d. Drop in water. This only works for plants which you plan to grow fully hydroponically. I plan on putting an airstone in there to help keep the water oxygenated for the two Pleuros which are growing hydroponically.
. e. Drop on land. This only works for "airplants". I threw five Tillandsias in there, and they're just sitting on the surface. I took the picture above before putting them in, just to cut down on the visual confusion.
. f. Attach to rock. I stuck some moss in the natural crevices of the rock faces, with a bit of coir. This was also after the picture above. I think I'll also glue something else onto the rock face, using the brown caulk as glue. I have a Dendrobium lichenastrum var. prenticei which is likely to go in there soon by this method.
So there you go.