"Low tech?" Or "high concept?" The "Walstad Method" rides again!

Being a lover of aquarium technique, culture, and trends, it's hard to imagine me NOT trying almost every technique that's out there to keep aquariums. Over a lifetime in the hobby and industry, I'll admit that I have played with a lot of ideas over the years. And without sounding really f---ing old, I've been around long enough to see things that were "tends" become "movements", and ultimately "approaches" or "techniques." And, even more interestingly, I've seen stuff go through those phases, then fall out of favor, only to be resurrected to go through the "cycle" once again!

Today's piece is a tale of advancements, embraces, rejection, and redemption... and education. Okay, maybe not that prosaic, but it encapsulates a lot of the way our hobby "works."

One of the classics that has sort of went this route is a planted aquarium approach called "The Walstad Method." Many of you have already heard of it, so I'll give about the most rudimentary summation of the concept, and you can rely on your fave search engine or whatever to "fill in the blanks" if you need a refresher.

Essentially, the approach was formulated by aquarist/author, Diane Walstad, and is quite impactful, if we dig down on it. Curiously, I met her once at a weekend show we were both speaking at in New England, when I was a reef-keeping "superstar" and, at the time, was far more interested in how to grow out sexy coral frags than I was to play with something as unsexy as a "natural planted aquarium."  (yeah, I admit, I was in the typical "arrogant reef keeping mindset" for like 15 years or so at that point...Freshwater was just "brown, grey, and outdated" to me at the time, even though I'd kept freshwater my whole life. Little did I know, huh?)

The idea is to provide a closed ecosystem where the plants and fishes work together to provide for each other's needs. Unlike a traditional planted aquarium, this approach utilizes a substrate comprised of rich soil, capped with sand, to keep the plants growing rapidly, and outcompeting nuisance algae, while providing nutrient export and nitrogen cycling via their lush growth.

I immediately found this to be fascinating. As a reef person, you become really attuned to "taking care of the ecosystem" of your aquarium in order for everything else to thrive. Well, either you learn to look at your reef as a little "microcosm"and care for the bacteria and other "lower" life  forms in the tank as an important component, or you simply suck as a reefer- and your tank will, too.

I'm been serious...As many of you know, reef tanks are absolutely dependent upon you understanding this concept. Nature will "hand you your ass on a platter" in the form of nuisance algae, dead corals, and sick fishes if you can't figure it out. Period. Full stop.

"Okay, just chill, Fellman...Go to your stinky mangrove thicket..."

SO-yeah, to make a long story short-  the idea of a sort of "harmonious" tank wasn't all that alien a concept to me...Niether was the attending "chatter" by hobbyists who are/were embracing the approach as a way to limit or avoid water changes as part of their maintenance. Seems like no matter how good a technique is for our aquariums, a certain segment of hobbyists will always find the 'lowest common denominator" ( ie; "reduced maintenance") and seize upon that as the biggest takeaway of the approach.

And, inevitably, when it turns out that said technique is NOT intended  to be a way to "reduce or eliminate water exchanges", doesn't support their "narrative of laziness", and results in the inevitable "issues" (algae, etc...) that arise when one takes shortcuts and fails to learn, it starts to fall a bit more "out of favor", and the more vocal corners (typically, lazy-ass hobbyists) shout, "Nothing to see here...move on..." and sort of serve to push it out of "relevance."

Her book, "Ecology of the Planted Aquarium" is an absolute treasure trove that every hobbyist should own and read. And study...and execute on once an understanding is gained on this stuff.  It's not a "look book" filled with pictures of contest-winning, non-sustainable fantasy scapes and fanboy-fueled marketing hyperbole and blindly reverent, "haiku-like" platitudes about Nature. Rather, it's a concise, thorough, and incredibly valuable reference on how the functions of natural aquatic systems work equally well in our aquariums- if we facilitate their processes, rather than edit and "sterilize" them. It's a book- and an approach- for thinkers.

Sound familiar?

So, yeah- there are lot of people for whom an approach like this (hey- Nature!) is simply not going to ever work, because they don't quite understand- or make the efforts to understand- the dynamics of nutrient cycling and interactions between plants and aquatic fauna. Typically, eschewing the "homework" and learning a bit more of the detail behind a technique like this leads to unhappy outcomes for some, who castigate it and deride it as "overhyped" or whatever. We love to simply "duplicate" something blindly without that effort to fully understand how it works...urghh.

Yeah. This is a familiar "aquarium culture" thing.

It needs to be exorcized from our collective hobby mindsets, IMHO. Well, that's what we've been trying to do here for a while- as have many of you.

Nonetheless, when I heard her talk about this idea, it was like I'd never put "2 and 2 together"  before with freshwater, and I was hooked. Something in my primal hobbyist brain clicked, and I immediately knew that, if I ever ventured back into freshwater aquarium plants, this was the way I'd go. Of, course, at that time, I was well into my blackwater aquarium obsession, and the ideas of replicating the form and function of blackwater habitats was already swirling in my head- and in my tanks of the era.

And she was most gracious and accommodating of what must have seemed like shockingly ignorant questions from me, "coral boy...."

And one thing I truly respect about Diane ( I don't know her personally-just met her once and have read a lot about her ideas and her approach- that's serious IMPACT!), is that she seems to have no desire to "dumb it down" to make this stuff more "palatable" to those who don't want to make the effort to go deeper and learn more. I love that. I found her to be affable, knowledgable, humble, and utterly fascinating- to the point where I flew home after the show and set up a freshwater tank the next weekend! 

Okay, great side story and personal admiration aside, the idea of a rich soil substrate that not only accommodates the needs of the plants, but provides a "media" in which beneficial bacteria can grow and multiply is a huge "plus" for our closed aquatic ecosystems. And the concepts of embracing Nature and her processes work really well with the stuff we are playing with.

The things I like best about this method are that you need to really wait a couple of months or so before adding fishes, until the nitrogen cycle stabilizes, and the fact that the technique relies far more on Nature than it does on CO2 systems, additives, and all sorts of other gear (that's my other "diss" on most reef keepers, but I"ll keep my mouth shut for now...). So, yeah- it espouses/requires patience, the learning and embracing of natural processes and "rules", and eschews "gear reliance" in favor of "brain reliance"- how could I NOT love this?

And that "ethos" sounds oddly familiar to our work with botanical-style natural aquariums (blackwater, brackish, and otherwise)- doesn't it? I'll even forgive the awful and insulting moniker of "low tech" that the planted world ascribes to this approach...I mean, is Nature "low tech?" Have you ever read a scholarly article about the nitrogen cycle? Absorb THAT and try to use the term "low tech" to describe this stuff. Talk to the guys at NASA who have spent decades studying natural nutrient processing to figure out how to build systems for waste management on future spaceships, and get back to me with that thought...


"Low Tech", my ass.

More like, "Nature Tech." 

(Damn, I'm fiesty today! Good coffee!)

So, how does this relate to our world?

Well, for one thing, you see me literally pounding the hell out of you every week (if not daily) about how it's important to create rich, botanical-influenced substrates and ecosystems, for the purpose of facilitating microorganism growth, supplementary food, and the fostering of biofilms and fungi for their possible benefits at enhancing the nutrient-processing capabilities of your little microcosm. 

The main difference is that aquatic plants, to many of us, are a "secondary" thing. However, fostering a little ecosystem is not. That being said, with more and more hobbyists creating blackwater planted aquariums, it's increasingly obvious that a) these systems are entirely compatible with plant growth, and b) the idea of "enriched substrates" via soil and/or botanical "supplementation" works well even for systems which don't focus on aquatic plants.

As you've seen over the past few weeks, I've been focusing a lot on my long-running "Urban Igapo" idea and experiments, sharing with you my adventures with rich soils, decomposing leaf litter, tinted water, immersion-tolerant terrestrial plants, and silty, muddy, rich substrates. This is, I think, an analogous or derivative  concept to the "Walstad Method", as it embraces a more holistic approach to fostering an ecosystem; a "functionally aesthetic" aquarium, rather than a pure aesthetic one.

The importance of incorporating rich soils and silted substrates is, I think, an entirely new (and potentially dynamic) direction for blackwater/botanical-style tanks, because it not only embraces the substrate not just as a place to throw seed pods, wood, rocks, and plants- but as the literal foundation of a stable, diverse ecosystem, which facilitates the growth of beneficial organisms which become an important and integral part of the aquarium. And that has inspired me to spend a lot of time over the past couple of years developing more "biotope-specific" substrates to compliment the type of aquariums we play with.

When we couple this use of non-conventional (for now, anyways...) substrate materials with the idea of "seeding" our aquariums with beneficial organisms (like small crustaceans, worms, etc.) to serve not only as nutrient processing "assistants", but to create a supplementary food source for our fishes, it becomes cool. As creatures like copepods and worms "work" the substrate and aerate and mix it, they serve to stabilize the aquarium and support the overall environment.

Nutrient cycling.

That's a huge takeaway here. I'm sure that's perhaps the biggest point of it all. And, the ability of decomposition to provide nutrition for plants- or in our case- for the overall system. You know, instead of pricy "mystery additives", "shortcut-creating" products, CO2 systems, etc.

There is so much work to do in this area...it's really just beginning in our little niche. And, how funny is it that what seems to be an approach that peaked and fell into a bit of disfavor or perhaps (unintended) "reclassification"- is actually being "resurrected" in some areas of the planted aquarium world ( it never "died" in others...). And a variation/application of it is gradually starting to work it's way into the natural, botanical-style aquarium approach that we favor.

Good times. Much learning and experimenting ahead.

Let's get after it. Do the work. Execute the experiments. Make the mistakes. Learn the process. Apply patience. Rinse and repeat.

Stay educated. Stay focused. Stay diligent. Stay open-minded...

And Stay Wet.


Scott Fellman

Tannin Aquatics 









Scott Fellman
Scott Fellman


9 Responses

Scott Fellman
Scott Fellman

September 20, 2020

Hey Rusty,

Thanks for the kind words…And as for the “quote..” I like to use them and it’s “my blog”, and… :)


(Yeah, I am " happy, for sure!)

Rusty Stork
Rusty Stork

September 19, 2020

Great article but lay off the ‘quotes’ that aren’t quotes. Reading your article was like talking with someone who used bunny ears constantly. Very distracting and kinda annoying. Cheers!

JJ Fox
JJ Fox

July 23, 2020

High tech planted tanks make reefing look like a cake walk. I started reefing recently (with a 2.6 For a first tank).

I’ve had no issues. It is dramatically easier to keep than my high tech planted tanks are, and I was expecting the same challenge. Not at all. Easy.

Scott Fellman
Scott Fellman

March 31, 2020

Hi Andrew,

We’ve been chatting about it for a while here in various blogs in “The Tint”. Here are a few links:




There are lots of others with titles which escape me by now…I’ll try to do a better job organizing them…otherwise, you have to just read ’em all!



Andrew Hines
Andrew Hines

March 27, 2020

Where can I find out more about your substrate experiments?

Scott Fellman
Scott Fellman

December 13, 2019

Gret question.

I realize that there are certainly ways to utilize some natural processes within the ecosystem to utilize various nutrients via algal/plant growth, etc. Nonetheless, I think that, for our purposes, the best way to “rehab” water for aquarium use (water which has high levels of ions or salts, that is), would be to employ a commercial reverse osmosis/deionization unit. I think there are all sorts of approaches one could experiment within the functioning aquarium system (liek a "refugium employing algae or plants, etc.), but for the source water itself, RO/DI is the most practical way to go, IMHO.


Annelle Kurtz
Annelle Kurtz

December 12, 2019

And: have you ever tried adding DRIED, crushed eggshells? they have fantastic nutrients in an organic garden system, things that cannot be provided by other ingredients. maybe a little bit of that inside your rich soil would boost the system? :)

Annelle Kurtz
Annelle Kurtz

December 12, 2019

tell me: is there a way to use this type of ecosystem to “rehab” mineral polluted water > high iron, slightly salty water .
I presume that one would HAVE TO first let the water oxygenate in a LARGE settlement tank for iron sedimentation. would you need to remove the sediment occasionally (perhaps planted “pots” that can be rinsed and placed back in the settlement tank? ) or very hardy rich-soil plants + constant waterflow ??? u know what i’m sayin’


other suggestions?

Annelle Kurtz
Annelle Kurtz

December 12, 2019


Leave a comment