"Extended operations...."

Hard to believe, but we're closing in on 5 years of operations here at Tannin Aquatics! Five years of sharing our vision of the botanical-style natural aquarium. Five years of talking about unusual ways to replicate the form and function of Nature in our tanks...Many of you have been with us right from the beginning. And quite a few of you were experimenting with botanicals and such in aquariums even before we emerged as a company!

Like us, you've been drawn to this alluring world of tinted water, decomposing leaves, and biological complexity...

The practice has begun to emerge from the shadows, shaking the stigma of "side show"; with you losing your "daredevil" status as a fish geek for trying a botanical-style tank as it moves into the main stream of the hobby.

One of the questions that were starting to see more of as we evolve in the blackwater, botanical aquarium specialty is, "What are the long-term implications for maintaining such tanks?" (okay, it's not always worded that succinctly, lol). Hobbyists are interested in how these systems function in the long term, specifically in regards to nutrient control and export processes...

Now, this is an area of great interest to me, as well.

Over the many years that I've been expert,ending with and managing blackwater, botanical-style tanks, I've placed a lot of emphasis on water quality and environmental consistency. Now, on first glance, the visual  impression you'd get from our practice is that these are "dirty", organic-heavy systems, with high levels of nitrates, phosphates, and dissolved organic compounds...Systems "teetering on the edge", if you will. 

And I suppose that's partially because of the very appearance of these tanks- filled with decomposing leaves, seed pods, accumulating biofilms, embracing detritus, etc. Oh, and that dark brown, tannin-stained water! On the surface, the uninitiated could easily conclude that you're playing with all of the ingredients for a potential disaster.

How long do you keep your botanical-style aquariums up and running?

A few months? A year? Several years?

As self-appointed "thought leaders" of the botanical-style natural aquarium movement, we spend an enormous amount of time talking about how to select botanicals, prepare them, and utilize them in aquariums. We talk about what happens when you place these terrestrial materials in water, and how botanical-style aquariums "evolve" over time...

All well and good...

However, we've probably talked a lot less about the idea of keeping these aquariums over the very  long term.

And, I'd define "very long-term" as a year or more.

I mean, this makes a lot of sense, because botanical-style tanks, in my opinion, don't even really hit their "stride" for at least 3-6 months. Yet, in the content-driven, Instagram-fueled, postmodern aquarium world, I know that  we tend to show new looks fairly often, to give you lots of ideas and inspiration to embark on your own journeys.

And I suppose, that's a very cool thing. Yet, it's likely a "double-edged sword."

Like so many things in the social media representation of today's aquarium world likely gives the (incorrect) impression that these tanks are sort of "pop-ups", set up for a photography session and broken down quickly. We are, regrettably, likely contributors to some of this misconception. 

I think we, as those "thought leaders", need to do more to share the process of establishing, evolving, and maintaining a botanical-style aquarium over the long term. To that end, we're going to do a lot more documentation of the entire process in months to come- documenting the journey from "new" to "mature"-sharing the ups, downs, and processes along the way.

Regrettably, the way this work is often presented on social media, it likely enables us to project our human impatience and desire or instant gratification on living creatures, which, in my opinion, is sort of the opposite of Nature's "timetable." She does things in a time and manner that are best suited for the creatures who reside in the natural world. There is no need or reason to conform to our timetable to get the aquarium cycled and stable "this weekend."

Besides, if the goal is to keep an aquarium functioning for the longest period of time, what's the rush to get it stabilized?

Patience, as always, is the key ingredient here.

Like with most types of aquariums, I don't think that there is an "upper limit" to how long you can keep a botanical-style aquarium up and running. It's predicated upon our ability to stick to a mindset...

The longest I've personally maintained such a system continuously has been about 5.5 years, and the only reason I broke down that aquarium was because of a home remodel that required the removal of everything from the space in which the aquarium was located. I set it up again shortly after the work was completed, keeping the substrate intact during the "move."

The reality, though, is that I could have kept this system going indefinitely. 

And the interesting thing about these tanks is that they run very, very well for extended periods of time, with simple, time-honored husbandry practices and mindsets.

As most of you who work with these aquariums know, the key to long-term success with them is to go slowly, deploying massive amounts of patience, common-sense husbandry, monitoring of environmental parameters, and careful stocking management. Not really much different from what you'd need to do to successfully maintain ANY type of aquarium for the long haul.

As we've discussed many times, for the longest time, there seemed to have been a perception among the mainstream aquarium hobby that botanical-style blackwater aquariums were delicate, tricky-to-maintain systems, fraught with potential disaster; a soft-water, acidic environment which could slip precipitously into some sort of environmental "free fall" without warning.

A scary and undeserved attribute ascribed to these tanks.

Most of us who have played with these types of aquariums have seen the exact opposite: Minimal, if any- detectible nitrates, phosphate, and remarkably stable pH values.

The reality is that, one the tank is "set"- that is, once you're done with the initial adding of lots of botanicals, and wood, and leaves and such...Like any tank, these tanks seem to "find" some sort of equilibrium. I've said it many times and I think that it needs repeating: In my opinion, blackwater, botanical-style aquariums are no more difficult or "dangerous" to maintain than any other type of aquarium we work with. They simply have different "operating parameters", which, one you learn, create stable, long-term viable systems.

There are always "warnings" that we receive from hobbyists about the "dangers" of flirting with materials which can lower the pH of our tanks under certain conditions. The so-called pH "crashes"- which I personally, in over 23 years of playing with this type of tank- have never seen. I just haven't. I know that's a big concern for a lot of people- and I won't downplay it or dismiss it. However, the reality is that I personally- nor none of my close friends who play with these kinds of systems- have ever experienced this. 

Are we lucky?


Do we practice overall good aquarium husbandry?


That means we do water exchanges. Like, 10% or more weekly. Every damn week. With the same kind of water (RO/DI). We clean/replace filter socks, pads, or any other media that we use. We don't feed recklessly. We don't overstock. We monitor basic water parameters weekly. We properly prepare and replace botanicals gradually and regularly.

Put is in for medals, right?

I mean, just because we do it with relatives ease and success doesn't mean that this is a piece of cake or anything. I get that. My point was not to "humble brag" or anything. Rather, it was to remind you that if a guy like me can be successful with this stuff, hobbyists with serious skill like you can REALLY be successful!

However, it should give you some comfort knowing that, in addition to just myself an a few friends, hobbyists worldwide are playing with botanical-laden systems without "anomalous" crashes and disasters. Can bad stuff happen? Sure. The most common "disasters" we've seen have been by adding too many botanicals too quickly, resulting in excessive bacterial respiration- which, in turn, likely lowered the water's dissolved oxygen and increased CO2 levels rapidly to a dangerous rate. These effects happen at the same time and can lead to fishes gasping for oxygen at the surface- or worse.

But that's the extent of the "bad" that I've seen.  

The idea of a pH "crash" is possible, I am sure...but I think it's largely avoidable, much like the CO2 increase. A pH "crash" is when the pH suddenly (and unintentionally) drops because of the release of acid into water with little or no buffering capacity...this can be dramatic and quick...But I think, once again, it would be caused because of our own actions- intentional or otherwise...Not something that is inherently "on standby" in a blackwater, botanical-style aquarium. Sure, we work with materials that can affect the pH..but it's not a ticking time bomb, if you add materials logically and slowly.

Observation and patience are keys. 

Now, I am not a chemist, and I'll be the first to admit that what I'm using to justify my position is largely anecdotal, based largely on my operating many such systems over the years. I have not done rigorous controlled experiments on this stuff.  That being said, I'd welcome those with the interest and knowledge to conduct some cool experiments to see what we can learn! I am really of the opinion that WE as hobbyists are the causative factor of many of these "anomalous" events in our aquariums. They can almost always be traced back to some action which triggered the event...

If your continuously adding materials which drive down the pH in your tank, and if it has insufficient buffering capacity- the pH will drop. How rapidly? Well, I couldn't' tell you. But I believe such "crashes" are quick, immediate responses to some causative factors. And I think they can be remedied equally as quickly. There is a lot of this stuff on hobby forums about working with pH, and quite frankly, I find it a bit too complex and tedious to understand and explain, so I recommend doing a "deep dive" on this stuff if it is a concern. There is great information by well-qualified hobbyist/scientists on this stuff. Look for it.

It's out there! 

What happens over time?

Well, typically, as most of you who've played with this stuff know, the botanicals will begin to soften and break down over a period of several weeks. Botanical materials are the very definition of the word "ephemeral." Nothing lasts forever, and botanicals are no exception! Pretty much everything we utilize- from Guava leaves to Melostoma roots- starts to soften and break down over time. Most of these materials should be viewed as"consumables"- meaning that you'll need to replace them over time to keep the desired results consistent. 

Oh, and sure, botanicals will go through that "biofilm phase" before ultimately breaking down, and you'll have many opportunities to remove them...Or, in the case of most hobbyists these days- add new materials as the old ones break down...completely analogous to natural "leaf drop" which occurs in streams, rivers, and flooded forests throughout the tropical world.

And of course, this always prompts the next question: "Do I leave my botanicals in the tank until they completely break down, or do I remove them?"

My advice: Leave 'em in.

I personally have never had any negative side effects that we could attribute to leaving botanicals to completely break down in an otherwise healthy, well-managed aquarium. Yeah, it will produce pieces broken-down botanical materials and...detritus. 

Well, you know how I feel about detritus. 

Many, many users (present company included) see no detectable increases in nitrate or phosphate as a result of this practice. Of course, this has prompted me to postulate that perhaps they form a sort of natural "biological filtration media" and actually foster some dentritifcation, etc. I have no scientific evidence to back up this theory, of course (like most of my theories, lol), other than my results, but I think there might be a grain of truth here!


I believe that the "microbiome" of a botanical-style tank, complete with fungal growths, biofilms, and decomposing leaves, is extremely diverse, and potentially quite beneficial for the resident fishes as a supplemental food production "facility" as well. My experiments with abstaining from feeding a leaf-litter-dominant tank for many months validated this.

Now, of course, you are dealing with a tank filled with decomposing botanical materials, so you need to stay on top of stuff.  Our embrace of natural processes aren't about simply abandoning all well-established aquarium husbandry practices. Botanical-style aquariums aren't just "set and forget." Good overall husbandry is necessary to keep your tank stable and healthy- and that includes the dreaded (by many, that is) regular water exchanges.

I know, I keep going back to this.

As we pointed out, at the very least, you'll likely be cleaning and/or replacing pre filter media as part of your routine, and that's typically a weekly-to bi-weekly thing. Part of the art and science of botanical-style aquarium-keeping is the idea of developing consistency, and understanding what to expect over the long term, as outlined above.

And yes- one of the most important behavioral characteristics I think we can have in this hobby, besides patience, is consistency.  

Just sort of "goes with the territory" here.

This is where those who don't understand these types of aquariums get it all wrong and really "short-sell" this stuff... It's about understanding and processing what's happening in the little aquatic ecosystem you've created. It's about asking questions, modifying technique, and, yeah, playing hunches- all skills that we as hobbyists have practiced for generations.

When you distill it all- we're still just "keeping an aquarium"- yet, one that I feel is a far more natural, dynamic, and potentially game-changing style for the hobby.

One that we need no longer be afraid of.


One that's perfectly equipped for "extended operations."

Stay engaged. Stay thoughtful. Stay patient! Stay focused. Stay curious. Stay dedicated...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


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