I’ve never set out to set up a tank with a theme before now. I’ve always found tropical calderas awe inspiring. These ancient volcanic rings, broken apart and flooded with crystal blue water that over millennia have ground the walls of the fiery mountain into black sand, provide a wonderful palette of colors and serene randomness that only nature can provide.
6’ long 125 gallon aquarium (All-glass)
Felt background (sky color)
Substrate and Harsdscape
ADA Amazonia and Africana
Various lava rocks from New Mexico
Black Diamond coal slag (decorative sand)
Used pea-gravel to build up the base
4 Kessil A650WE Amazon Sun
Kessil light controller
Filtration and Heat
2 Eheim 2217 canister filters
2 Hydor 200 in-line heaters
JBJ temperature controller
Custom dual-stage Praxair regulator, Swagelok valve, Burkert solenoid
Rio+ 800 PT (needle wheel) with Eheim spray bar
Water and Fertilization
Tap water - water softened (KCl) to strip Ca+ and MG+
Week 1 water parameters
KH = 1.5 deg
GH = 17 deg (due to CaSO4, MgSO4 supplement)
pH (am) = 6.4
pH (pm) <= 6.0
NO3 = 10-15 ppm (uncalibrated API kit)
NH4 = .25 ppm (uncalibrated API kit)
- Possible lemon or pristella tetras, flame gourami, pygmy corys, Daisy’s rice fish
Anubias nana ‘petite’
Bacopa australis (~2 week dry start)
Elatine triandra (~2 week dry start)
Eleocharis belem (2.5 month dry start)
Hydrocotyle tripartita (> 3 month dry start)
Limnophila ‘mini Vietnam’ (~2 week dry start)
Micranthemum tweediei (> 3 month dry start)
Pogostemon helferi (> 3 month dry start)
Rotala mexicana ‘Goias’
Staurogyne repens (~2 week dry start)
I have several goals with this layout. I am going for good presentation from two sides, so I attempted to heed the rule-of-thirds from the short side (18” wide) as well as the front. I am also interested in executing what I call ‘painting with plants’. By borrowing from classical landscape painting concepts, I intend to achieve depth by laying out the plants with higher color and texture contrast at the front of the tank, and ‘blurring’ the detail towards the back of the tank by the use of relatively pale ground cover plants. As I am working with elevation, it is relatively easy to push the carpet plants to the background and bring taller foreground and smaller mid ground plants to the front. This is a tricky balance in order to preserve a sense of height scale as well. Taller plants toward the back of the scene will undoubtedly make the illusion harder to sell to the viewer.
As seen above in the full view, something is missing on the middle beach and the right grass. I’m thinking a half-round of small Lobelia cardinalis will help the middle interest, and give me a street of S. repens wrapping around behind it into the E. triandra. Some Syngonanthus madeira among the front third of the hairgrass would make for some interesting balance, provided I keep them pruned to 4 or 5 inches or so.
Right front view
Currently the weakest view in execution. The idea here is for the Bacopa australis in the back to become a sloping mound towards the Hydrocotyle (temporary) on the back mid tier. The Rotala ‘Goias’ should be carpeting behind the downoi and into the Bacopa mound. My original concept called for the H. pinnatifida to drape its leaves over the Rotala. Having never grown this before, I hadn’t realized just how tall this plant gets. It is a scale buster. Here I have a lone young stem. I’d wanted 3 of these for this spot, but now I need a plan ‘B’. The DHG didn’t spread as quickly as I’d hoped, either. I need this to spread up the front towards the downoi. I need the Rotala to spread down towards the DHG. I need to not get gypsum on the black sand...
Can you pick out the Hygrophila polysperma among the S. repens? Maybe I’ll leave it, like a rogue eyebrow hair that is always sticking out. Need to move the Limnophila near the downoi up and against the rocks, and spread the downoi left and up a little for a smoother transition (same texture, lesser detail).
Left side view (3/4 overhead)
Here you can see the Anubias, intended to be enjoyed from the left side view.
Left side view
Once the growth gets established I’ll thin out the Hydrocotyle and chop it an inch or two.
Lessons already learned
Using a typical 125 gallon aquarium, I discovered quickly that the trademark bowl of the caldera rim would be difficult to pull off with only 18 inches of depth (front to back). Lava rock is ‘lighter’ in water than it is in air, and should be stacked with the aid of epoxy. Buce should be secured to the rocks as well, as the current does work them out of the crevices in time, at least until the roots take hold. M. tweediei dry starts better in dry dirt than it does in saturated dirt. Aqua-soil is light, and blows all over the place.
Week 1 problems
S. repens appears to have melting leaves on the bottom, yet it is continuing healthy growth upwards. I’d suspected a NO3 deficiency, but (uncalibrated) measurements show 10-15 ppm. Some E. triandra is showing this, too, yet to a lesser extent.