My "new" aquarium (cut for width):
This is my old 75-gallon tank, which some of you may remember as having once been saltwater. A series of environmental disasters and toddler interventions rendered it essentially unfit for marine life this summer, so the inhabitants were moved into my other tank. This one then sat empty for WAY too long, as I decided what to do with it, and then waited for the money I would need to properly outfit it.
I decided to set it up as a planted freshwater aquarium, with an attempt to represent, after a fashion, a flooded Amazon forest environment (please note - I realize not all of the plants in the tank would appear in such an environment; believe me when I say it was the best batch from a poor selection that was available to me).
The tank has a three-layer substrate with no undergravel filter. There is a low-watt heating cable running along the bottom of the tank, and this is covered with a layer of fine white non-reactive sand that won't raise the pH of the water. There is then a thin layer of laterite (aquarium plant food/fertilizer) on top of this, and then a two-inch later of stream gravel on top of that. I would have tried for a more authentic soil-like substrate for the top layer if I hadn't read what an absolute pain they were to take care of, clean, and prevent from choking the filter.
In addition to the layer of food in the substrate, I'll be using a CO2 kit to fertilize the plants. I'm not comfortable with a pressurized gas canister around my children (currently 3 & 5), so I'll be using a dissolving-tablet system from Sera. That's the green box visible in the upper left of the tank, right above the magnetic algae scraper. The small clear plastic box in the upper left front of the tank is a long-term CO2 indicator that will warn me when levels are too high or too low.
The big green heater in the front of the tank will go away as soon as I receive the in-line heater I ordered (they forgot to ship it the first time). This is a keen little device that will be attached to the outflow of my external filter and heat the water as it passes through; this will wipe out the possibility of any of the plants or animals in the tank burning themselves on the normal style of heater (like the one shown here now) - it also helps the visual aesthetics of the tank because I won't have to try and hide the heater.
The external filter intake is on the lower right back of the tank; the outflow is at the upper left, near the CO2 boxes, and is directed diagonally across the top of the water to allow for gentle aeration and a good water flow that won't unduly disturb the plants. This is the same filter I used when this tank was saltwater, but it is much better suited for this type of application.
Finally, I'm using a glass-top system of the kind usually seen on the larger tanks (versus the plastic-and-glass combo canopies you usually see on tanks 30 gallons or less) to allow as much of the light for the plants through as possible. On top of this I have a 48" Coralife Aqualight Freshwater compact fluorescent fixture, with four 65-watt 6700K bulbs. Currently they cover pretty much the entire tank, but I'm hoping to find some nice floating plants that will help break the light up a bit.
The tank has only been up for four days at the moment; we won't add any fish in for another 2-1/2 weeks, in order to give the ammonia-eating bacteria culture I added in time to colonize the filter. Once we do add fish, our first batch will likely be a shoal of 6 lemon tetra and six silver-tipped tetras. The next batch (two weeks later) will include four cory cats, a small shoal of cardinal tetras, and either some bleeding-heart or head-and-taillight tetras. Finally, three weeks after that, we'll add in six juvenile angelfish, a clown plec, and a shoal of hatchetfish.
If I have time, I'll put additional pictures up of each stage. With any luck, by the time the last fish have been added it should look spectacular.