After over 5 years of evolving Tannin Aquatics, decades of playing with leaves and twigs, and (hopefully), being one of the more vocal proponents of botanical-style aquariums, I've definitely learned a bunch of stuff, right along with all of you!
As a result of this, we've been able to determine some characteristics and "behaviors" associated with their use as dynamic hardscape materials. We may sound absurdly repetitive at times, but you -our customers and fans- want to know all of the ins and outs of this stuff, and we're happy to oblige! And thanks to your inout, we have a lot of good information to share!
We've been able to really "drill down" on a few things and I thought I'd share some of our "pearls of wisdom" based on my personal, and our community's observations on use of these materials in our aquariums:
1) Botanicals are not "forever" aquascaping materials.- We consider them ephemeral in nature. They will soften, break down, and otherwise decompose over time. Some materials, like leaves- particularly Catappa and Guava, will break down more rapidly than others, and if you like the look of intact levels versus partially decomposed ones, you'll want to replace them more frequently; typically on the order of every three weeks or so, in order to have more-or-less "intact" leaves in your tank.
On the other hand, if you're like me, and enjoy the more natural look that occurs as the leaves break down, keep 'em in. You may need to remove some materials if you find fungal growth, biofilm, or other growth unsightly or otherwise untenable.
Botanicals like the really hard seed pods (Sterculia Pods", "Cariniana Pods", "Afzelia Pods"), etc., can last for many, many months, and generally will soften on their interiors long before any decomposition occurs on the exterior "shell" of he botanical. In fact, they'll Miley recruit biofilms, which almost seem to serve as a sort of "protective cover" that preserves them.
Often times, fishes like Plecos, Otocinculus catfish, and other bottom-dwellers, will rasp or pick at the decomposing botanicals, further speeding up the process. Others, like ornamental shrimp, Apistos, and others, will pick at biofilms covering the interior and exterior of various botanicals, as well as at the microfauna which live among them, just as they do in Nature.
2) Virtually all botanical materials will impact the color of the water. -You'll find, as we have, that different materials will impart different colors into the water. It will typically be clear, but with a golden, brownish, or reddish tint. The degree of tint imparted will be determined by various factors, such as how much of the materials you use in your tank, how long they were boiled and soaked during the preparation process, and how much water movement is in your system.
Unfortunately, since these are natural materials, there is no set "X pods per ___ gallons of aquarium capacity", and you'll have to use your judgement as to how much is too much! It's as much of an "art" as it is a "science!"
3) If you really dislike the "tint", but love the look of the botanicals- You can mitigate some of this by employing a longer "post-boil" soaking period- like over a week. Keep changing the water in your soaking container daily, which will help eliminate some of the accumulating organics, as well as to help you to determine the length of time that you need to keep soaking the botanicals to minimize the tint.
Of course, it's far easier to simply employ chemical filtration media, such as activated carbon, and/or synthetic adsorbents such as Seachem Purigen, to help eliminate a good portion of the excess discoloration within the display aquarium where the botanicals will ultimately "reside."
4) You'll notice over time that many of the botanicals will "redistribute" throughout the aquarium- Yeah, they're being moved around by both current and the activities of fishes, as well as during our maintenance activities, etc. This is, not surprisingly, very similar to what occurs in Nature, where various events carry materials like seed pods, branches, leaves, etc. to various locales within a given body of water. In our opinion, this movement of materials, along with the natural and "assisted" decomposition that occurs, will contribute to a surprisingly dynamic environment!
5) Your aquarium water may appear turbid at various times- As bacteria act to break down botanical materials, they may impart a bit of "cloudiness" into the the water. Also, materials such as lignin and good old terrestrial soils/silt find their way into our tanks at times. One of my good friends, and a botanical-style aquarium freak, calls this "flavor"- and we see it as an ultimate expression of a truly natural-looking aquarium.
Yeah, the water itself becomes part of the attraction. The color, the "texture", and the clarity of the water are as engrossing and fascinating as the materials which affect it.
Need a bit more convincing to embrace the charm of the water itself in botanical-style aquariums? Simply look at a natural underwater habitat, such as an igapo or flooded varzea grassland, and see for yourself the allure of these dynamic habitats, and how they're ripe for replication in the aquarium. You'll understand how the terrestrial materials impact the now aquatic environment- fundamental to the philosophy of the botanical-style aquarium.
6) Just like in nature, if new botanicals are added into the aquarium as others break down, you'll have continuous influx of materials to help provide enrichment to the aquarium environment. - As hinted above, this type of "renewal" creates a very dynamic, ever-changing physical environment, while helping keep chemical changes to a minimum.
The fishes in your system may ultimately display many interesting behaviors, such as foraging activities, territorial defense, and even spawning, as a result of this regular influx of "fresh" aquatic botanicals. You could even get pretty creative, and attempt to replicate seasonal "wet" and "dry" times by adding new materials at specified times throughout the year...The possibilities here are as diverse and interesting as the range of materials that we have to play with!
The whole idea of using botanical materials in aquariums is not entirely new, as it has long been known that these natural materials provide various chemical benefits to the aquarium inhabitants.
However, the idea that these materials can help form the basis of a functionally aesthetic aquarium environment- one in which they form a direct influence on the chemical, physical, and aesthetic environment of the tank- is fundamental to our "practice."
A less rigidly aesthetically-controlled, perhaps less "high-concept" approach in the eyes of some- setting the stage for...Nature- to do what she's done for eons without doing as much to "help it along." Rather, the mindset here is to allow nature to take it's course, and to embrace the breakdown of materials, the biofilms, the decay...and rejoice in the ever-changing aesthetic and functional aspects of a natural aquatic system-and how they can positively affect our fishes.
We're seeing that not only do leaves, botanicals, and alternative substrate materials look interesting- they provide a physiological basis for creating unique environmental conditions for our fishes and plants. We're seeing fish graze on the life forms which live in and among the decomposing botanicals, as well as the botanicals themselves- just like in Nature...And we are seeing the influence- aesthetically and chemically- which these materials assert on the aquarium's environmental parameters.
With more and more hobbyists playing with botanicals and experimenting with as a foundational part of the aquatic environment, we're excited to see what kinds of creative ideas arise out of the botanical-style aquarium movement!
We look forward to seeing what you come up with! Embrace "the tint!"
Stay creative. Stay motivated.
And stay wet!