Questions, answers, and ideas on the botanical frontier...

Every once in a while, we'll receive questions from our community, or from aquarists interested in the blackwater, botanical-style aquarium arena, about a variety of topics which we think would be of interest to a lot of people. 

Today, we're answering a couple of good ones, which are sort of "big picture", and might offer some good basis for future research and conversation. They're certainly not the last word on these topics, but I think they might sort of function as "position statements" we can build upon.

Q- You place a lot of emphasis on the stuff on the bottom of the aquarium. How does this differ from "active susbstrates" for planted tanks, and are there other benefits for aquariums that you can gain by using botanicals as the substrate?

A- I think one of the most "liberating" things we've seen in the blackwater, botanical-style aquarium "sector" is our "style" of utilizing the bottom itself  to become a feature aesthetic point in our aquariums.

In other words, the bottom itself becomes a big part of the aesthetic focus of the aquarium, with the botanicals placed upon the substrate- or, in some cases, becoming the substrate! Much like in nature, the materials that we place on the bottom of the aquarium will become an active, integral part of the ecosystem.

This is a big aesthetic shift in the hobby, but it goes beyond that. I mean, sure, we've done hardscapes before, with wood and stones dominating the 'scape. However, our tanks have placed far more emphasis on the "functional" aspects of the botanical materials we use. They've become not only physical places for fishes to hide and forage among- they've become an integral part of the entire closed aquarium ecosystem itself, helping influence water parameters, foster growth of fungi and microorganisms, and just maybe- some form of nutrient export/denitrification (although that last part is still a bit speculative).

It's certainly no stretch to call our use of botanicals as a form of "active substrate", much like the use of clays, mineral additives, soils, etc. in planted aquariums. Although our emphasis is on creating specific water conditions, fostering the growth of microorganisms and fungi, as well as creating unique aesthetics, versus the "more traditional" substrate materials fostering conditions specifically for plant growth. We've talked about "functional aesthetics" created by botanicals in the aquarium, the potential for additional biological support/filtration (and potentially even denitrification), and it's a big, BIG topic, with lots more to be explored,  discovered and deployed in our aquarium.


QCan you have "too much" tannins in your aquarium?

A- That's a tough question to answer. I mean, you can always have "too much" of anything, especially in the confines of a closed-system aquarium. Now, botanicals (leaves, seed pods, etc.) can release significant amounts of tannins and humic substances into the water (as they do in nature). Humic substances are documented by science to positively influence the health of fishes. Tannins will influence the the visual tint of the water, as well as the pH to some extent.

Obviously, having a lot of decomposing botanical material in a closed system impacts the nutrient load, can influence the pH (in a soft-water environment), and overall nutrient load. That being said, if you're on top of your water parameters (via regular testing and observation), managing a blackwater, botanical-style aquarium, even with a lower pH, is not that difficult.

You need to understand the relationship between the materials present in the system and the closed environment. I believe that there is a lot to learn about the microorganisms and other fauna (like fungi) which are present in botanical-influenced systems, as we've discussed many time here.

So, yeah, I suppose "too much" tannins could drive down the pH to rather low levels, creating a dynamic that requires more "situational awareness" of what's going on in your tank. You'll need to observe and test more often- no different than any other type of system.

In the end, we have accomplished quite a bit in the years in which the "New Botanical" movement has taken off- building upon decades of previous experience and experimentation in this arena. And the future...although somewhat tinted- is really bright!

Thanks for making the future happen!

Stay experimental. Stay excited. Stay creative. Stay diligent. Stay objective. 

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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