I gave this a lot of thought today, actually...If you had to ask me to name what I think might be the most important and dynamic aquatic botanical we offer, I think it just might be "Fundo Tropical." Why is this? Because it can really help turn your biotope aquarium into a real "slice of the bottom." When mixed with more typical aquatic substrates, like sand or fractured clay gravels and such, it creates a substrate that looks almost dead-on like the bottom of a tropical stream.
Made from coconut fiber, it's lightweight, clean, sustainably sourced, and leaches just enough tannin into the water to create that "blackwater look" we so admire around here! You need to boil the stuff for a while to get it to sink, and then my advice would be to soak it in freshwater for a week or more, as it will continue to leach out tannins for some time- and you never want to overwhelm a system.
When you mix it in with other materials, including some seed pods, leaves, and other aquatic botanicals, it will ultimately recruit some bofilm and other particulate, attracting grazing fishes, shrimp, and some micoralgae, to take on a look so natural, you'd swear that you just dug up some substrate in the Amazon River system!
We're talking about substrates that are dynamic, natural-looking, and natural-acting- harboring valuable ecofauna, creating a literal foundation for a highly successful biotope aquarium.