I've been lurking this board and a few others for a couple months while I designing my paludarium. I started the construction today, and figured I should start a construction journal. Hope this isn't too long winded, but after reading through dozens of builds I found that for someone wanting to try re-create some of the things I was reading about and come up with a plan, more details were better than less.
Beginning with a 40G breeder aquarium, I plan to build a large paludarium cabinet around it. Glass panels will add 2' to the top of the aquarium, meaning the final dimensions will be 36" long x 18" wide x 40" tall.
There will be two land portions within the aquarium, built using plexiglass that has been heated up and bent to shape, before being siliconed into the tank. The first will start at the right side of the tank, 6" from the front wall, and bend back towards the back edge, paralleling the back wall up to a point about 5" from the left wall, where will turn into the back wall. The second island will be in front of that last 5", creating a lagoon to hide the overflow. The plexiglass will be 10" tall. The return line from the sump will be drilled into the plexiglass on the side opposite of the lagoon, to create water flow from right to left across the tank. The plexiglass will be coated in silicone and then covered in sand to create a background below the water.
The background above the water line will be great stuff foam, covered with a mix of peat and coconut fiber.
I've already got a couple of lights from when this was an aquarium, one full spectrum, one with moon lights. I'm going to use these on timers (as well as adding a couple more full spectrum lights) to create a day and night effect. I purchased a fogger and some drip plumbing, which I will put on separate random timers to add humidity and (plus I think they just look cool). I'm debating putting in a mist king system. I think I'll start with the drip and go from there though.
Plexiglass land portions
Had I been thinking before I started this, I would have drilled the hole for the return line before putting this into the tank. Fortunately, my drill with the bit on was the exact length I built the widest portion of the land.
I didn't take any pictures of the plexiglass as I was bending it, but it actually went quite well. I'm glad I did this in the winter, as I could quench the plexi in the snow when I thought I had the desired shape.
Once I got to a shape I was happy with and had dry fit everything, I put a bead of silicone (GE 1) along the bottom edge of the plexi, and set it in the tank.
Up until this point I had debated buying a flexible universal rocks 3D background like I have in my 55g cichlid tank, and cutting it down into a 10" strip to fit the plexi, but after seeing the results of smearing silicone onto foam and covering it with dirt for terrarium backgrounds, I decided to try that with sand / rocks as well.
Again, this probably would have been easier to do out of the tank, and if I were to try in from in the tank again I would have masked off the glass to save some clean up.
Regardless, once the plexiglass was installed and silicone had started to harden, I started smearing silicone onto the plexiglass. I started with a back edge in case I didn't like it, and then finished off the rest. Part way through I decided that if I apply the silicone a bit thicker and finished with horizontal lines, it would look somewhat like sedimentary beds.
I'm happy with how it turned out. It isn't 100% opaque, but I figure once filled in there won't be any back light and it will look fine. I got a good deal on a bunch of bio balls a while back, and still have a very large box full of them. I'm planning on filling both portions with those once holes are drilled and bulkheads installed, and then putting progresively coarser substrate in (pebbles, gravel, flourite, dirt, then peat / coconut) on top of the bio balls.