According to this link, the Orinoco basin substrate is mainly mud and peat, with sand more prominent further upstream.
I ordered a canister filter, and have found out the hard way about hatchetfish jumping out of the tank, when I had freshwater aquariums in the 70's and early 80's before I switched to a coral reef tank. I'm now back to freshwater, since I'm involved with freshwater ecological research at work. Also, after snorkeling in a coral reef near Cancun, I realized that my saltwater corals were tiny, even in my 180 gallon tank.
I set up a local biotope tank last year. Local for me was lakes around Madison, Wisconsin (Yahara River watershed). That setup is as follows:
75 gallon tank, CO2 injection (DIY with a cylinder), 3 T12 6500 K, maxi-jet 600 powerhead with a sponge prefilter. Water is 50-50 RO water and Tap (which is very hard). Substate is top soil on the bottom mixed with calcite clay and diamond pro, covered with #15(?) flint.
The plants are P. Illinoisensis, elodea, stargrass, Vallisnaria (which has flowered several times), Eurasian millfoil, hornwort, and duckweed. I'm fighting an algae problem caused from some neglect and fish overstocking - I was working a lot on my reef tank at the time. Right now, I'm not losing plants to the algae, and I think I've turned the corner - algae growth has dramatically slowed down, and my plant growth has picked up.
I'm glad to see all of the new insights on how to make most plants flourish. Back in my freshwater days, undergravel filters in addition to overhanging power filters with activated carbon were commonly used, and really didn't give the plants a chance to grow well and consistently.
Of course, today, the internet can make up for a lot of bad advice given out at large chain pet stores (which still happens), but I haven't found much on biotope tanks.
Mongabay.com and belowwater.com have been the most helpful for my Orinoco biotope information. My overall favorite general aquarium site was wetwebmedia.com when I had my reef tank. I'm not sure about how helpful they are for planted aquaria.
Has anyone come across some other good info - either websites or books on setting up biotope tanks?