Home built background incorporating built-in filtration. The structure of the background consists of cellular polystyrene foam slabs carved and melted into shape, glued to tank sides and glass structure of the filtration chambers. Most of the polystyrene is covered in a very thin layer of cement with yellow and red ferrous oxide and yellow chrome oxide colouring. The whole is coated in several thicknesses of epoxy resin sprinkled with sand and coloured with brown ferrous oxide. The tree root built into the background is made of PU foam, also coated with several thicknesses of epoxy with a neutral filler.
The background of the land area was built separately of the same materials, incorporating niches for the plants. Strips of glass are glued to the backside of this background slab, and these were siliconed to the glass of the tank after assembling the cabinet for the paludarium. All the plant niches have drain holes and the relief of the slab is designed so that water pumped up into the background will reach all of them.
2 86.5 cm HO (39 W) T5 tubes, one pink for the plants (Osram Fluora), the other a high-Kelvin tropical light. On from 9 am to 10 pm every day.
3 20-watt halogen spots for ambient lighting and sunrise/sunset simulation, on from 8:30 to 9 am and 10 pm to 11 pm every day.
Homemade built-in filtration. The filter area in the back left of the tank consists of three chambers, each 9x9 cm in area and full-height (50 cm). Water is sucked into the first chamber near the bottom of the tank and travels upward through a coarse open-cell sponge for pre-filtration. Near the top it flows over into the second chamber, from where a small part of the flow is directed during the daytime up into the land-area background by a small-output pump through a tube built into the land background. The majority of the water goes on down through a fine sponge filling the second chamber, and at the bottom of the chamber goes over into the third. This houses the hidden heater, the CO2 output tube and a 900 litres per hour pump that directs the water through an opening in a jet along the background of the tank. The water pumped up into the land background reaches a horizontal tube hidden along the top of the background, from where it trickles down in several streams, wetting all the plant niches. Finally it reaches a trough built of glass and hidden by the background, along the back top of the tank. This trough is filled with clay granules and lets water flow back into the tank right next to the third filter chamber. Biological filtration is taken care of by the land plants and mosses, and by the clay granules in the trough. This small pump is on a timer that turns it off for the night so the plants in the land background are not soaked in water all the time.
It has been my dream for a long time to create a paludarium that resembles a Southeast-Asian backwater in the jungle. Paludarium may not even be the best word to describe it: it contains no actual “shore”, only a vertical dry-land background. I had started with a tank half this size that had an equal volume of airspace over it, but no land background, only emergent plants. I have kept the basic arrangement for this setup: rather than using a huge tank half-full of water, I preferred (both for ease of reaching inside and for cost efficiency) to build the bank section above the tank separately. If I can ever afford one twice as big again, I’ll probably do the same.
I never wanted the aquarium to be a true and faithful biotope, as its primary purpose is pleasure and not biological precision. Most of the plants and animals living in it are species that do occur in South and East Asia, but definitely not all of them in the same habitat. The only complete strangers to the crowd are the Otocinclus, whom I introduced about a year and a half ago hoping to keep green algae down.
The setup is presently two and a half years old. I have experimented with several plant species and there were times when I had more species of gouramis in it. Because the lighting is so high above the water surface and because of my floating plants, relatively little light reaches the bottom of the tank. I used to have some Sagittaria in the foreground, but it grew leggy and I have removed it. I’ve also tried other background plants including Cabomba and Aponogeton, but these did not like the conditions, nor did Microsorum, which is supposed to tolerate low light very well. I used to have one attached to one of the driftwood pieces, but it wasted away and died over the years.
Initially I used to have a different species of Nymphaea with much larger leaves. It had flowered several times (in this tank and in its smaller but similar predecessor), but to achieve that, I had had to let it cover all the water surface with leaves and even attach some to the sides of the airspace. My current waterlily was bought as a submerged plant this last winter and started growing floating leaves in the spring. I am letting it grow them in hopes that it too will flower but if it does not, I’ll mercilessly pinch off the floating leaves and force it to remain submerged.
I used to have a stand of Cyperus in the right back corner, but I had to remove it when it outgrew the tank. The long-leaved Hygrophila in the back left corner is usually allowed to emerge from the water, but by last winter it grew so huge and bushy that I have cut it down entirely, replanting a cutting of it which is just now reaching the surface.
I am also growing a couple of Cryptocoryne (both species) emerged, in the corner next to the filtration chambers and in the back filtration trough. The wendtii in the filtration corner flower regularly.
The climbing Ficus grows rampant all over the place and needs severe trimming. The dwarf Ficus trees also need to be trimmed often, particularly the one on the right-hand side that has let an aerial root grow down all the way into the tank water and must be sucking up nutrients like mad. The others sharing the niche with it seem not to be getting quite enough trace elements and I may decide to kill off a couple of them in the future. The Syngonium took over a year to adapt to the conditions, almost dying off in the process, but is now growing wildly. The Fittonia was initially planted in the filter trough, as it is supposed to tolerate very wet conditions, but it barely remained alive there. I have replanted it to the top left niche where it absolutely thrives in the light.
I have not had much luck with ferns. My bushy Adiantum died off after about a year and the top right niche has been empty ever since, though the climbing fig appears to grow from there. The Pteris fern probably found the top left niche too wet for its taste, so I have moved what was left of it to the bottom left one that gets barely a trickle of water. It is growing now, but is much smaller than its original size.
The jewel orchid loved the place initially and rewarded me with three flowering stems when the setup was a year old (it was in flower when I first put it in there), but then started withering and is in a pretty sorry state now. I am thinking of spooning out the substrate from its niche and replanting a cutting or two in fresh, airier stuff.
Most of the land background is now covered in Java moss, and a couple of other mosses (imported with the potted plants and collected from forests) grow on the grapevine wood and in the plant niches. Interestingly, the Java moss does not spread to the submerged part of the background. The tank is well settled and gives no trouble apart from fortnightly water changes (about 20%). I add small amounts of liquid plant food after water changes and occasionally push homemade nutrient pellets of laterite, clay and a trace-element mixture down next to the roots of larger plants. In the summer, when the tank gets some direct sunlight, I have to fight against green algae, but otherwise the otos, flying foxes and shrimp keep the tank practically alga-free.
More about technology
I use simple yeast CO2 from spring to autumn. The air tube conducting the carbon dioxide ends in a small plastic bell to gather the gas, housed in the third filtration chamber. A small PC fan built into the hood of the tank is switched on for about half an hour in the morning, at midday and in the evening, blowing into the paludarium airspace to add fresh air, dry the emergent plants a bit after being drenched in water throughout the day and cool the interior down a bit. Water is maintained at 25 °C by a thermostat heater (200 W), which is also switched off for the night, so from autumn to spring, when room temperature is below 25 degrees, the water cools to about 24 °C, but not much lower by the morning. Because of the heat of the T5 tubes, daytime temperature in the airspace is usually around 30 degrees, sometimes more on hot summer days. Humidity at the very top of the airspace varies between 60 to 70 percent.
Except for the glass tank itself, everything including the cabinet is the work of my own hands. The sides are glass panes attached both to the cabinet and to the tank sides. There are air slits at the top of these side panes. The front consists of two sliding glass panes so it is easy to reach inside at either side or in the middle, and the panes can be removed altogether for cleaning. The wiring and technology are almost 100% hidden in the background, yet everything can be manipulated and removed if necessary.
Fittonia verschaffeltii (argyroneura?), nerve plant
Ficus sp. (a benjamina cultivar), dwarf Java willow
Syngonium x ‘Pixie’, dwarf arrowhead plant
Ficus pumila, climbing fig
Pteris sp., unidentified fern
Ludisia discolor, jewel orchid
Vesicularia dubyana, Java moss
two or three further species of forest moss
Trichogaster leerii, pearl gourami — 5
Trigonostigma heteromorpha, harlequin rasbora — about a dozen
Kryptopterus bicirrhis, glass catfish — 5
Crossocheilus siamensis, Siamese flying fox — 2
Botia striata, striped Botia — 5
Otocinclus sp. — 3
Caridina japonica, Amano shrimp — 5
Melanoides tuberculata, Malayan live-bearing snail — hundreds, probably
two other species of small pond snails — a couple dozen, kept in check by the Botias
Bottom layer of substrate: sand mixed with peat, clay and laterite. Middle layer: rough sand. Decorative top layer: fine reddish quartz pebbles. I built ridges along the bottom of the same materials as the background; only the deeper substrate behind the ridges includes the nutritive layer. The plants in the above-water background are rooted in a mixture of rough gravel, charcoal, peat and coconut fibre.
Several pieces of driftwood, some store-bought, some self collected. Two half coconut shells. The land section includes a long willow branch and a gnarly grapevine stem attached to the background. Several small rocks and large pebbles, all smooth and dark-coloured, quartz and basalt.