Mixing it up: Going against what we know and love.. "Substrate Edition"

As you know by now, I have an obsession with substrates. Maybe even a fetish of sorts. Like, I really am into them. 

And one of the thing I’m into is “sediments.”

Yeah, I've always looked substrate materials the way other people look at cocktails: It's about mixing stuff. Yeah, seriously. That was sort of the genesis for our soon-to-be-released“NatureBase” substrates.

A mind set.

Now, in Nature, there are numerous factors which contribute to the composition of substrates in wild aquatic habitats, including geology, the flow velocities of the body of water, the surrounding topography, the seasonal variations in water level (ie; inundation/dessication cycles), and accumulation of materials from the surrounding terrestrial environment.

So, why do we as hobbyists, who want to create the most realistic approximations of wild habitats possible, just "mail it in" when it comes to substrate? I mean, just open a bag of _____________ sand or whatever, and call it a day and move on to he more "exciting" parts of our tank?

I think we just rely on the commercially available stuff and that's that.


Now, in defense of the manufacturers of sands and gravels for aquarium use- I love what they do, and what they have available. These items are of generally excellent quality, provide a wide range of choices for a variety of applications, and are readily available.

However, IMHO, they are a great "starting point" for creating more dynamic substrates for our aquariums. Kind of like tomato puree is to pasta sauce...a beginning! Sure, you can use just the puree and enjoy your sauce, but isn't it always better to add a bit of this and that and build on the "base"to create something better?


Or, you could use some of the stuff we've been playing with.  

 Of course, here's a little advice: The "NatureBase" substrates are not your typical aquarium substrates.

The idea of they were really created to replicate the substrate materials found in the igapo and varzea habitats of South America, and the overall habitat- more "holistically conceived"-not specifically for aquatic plant growth. And, in terrestrial environments like the seasonally-inundated igapo and varzea, nutrients are often lost to volatilization, leaching, erosion, and runoff..

So, it's important for me to make it clear again that these substrates are more representative of a terrestrial soil, and are not specifically formulated to grow aquatic plants luxuriously. Interestingly  the decomposition of detritus and leaves and such in our botanical-style aquariums and "Urban Igapo" displays is likely an even larger source of “stored” nutrients than the CEC of the substrate itself, IMHO. 

An added benefit of these types of substrates is that they will provide a home for beneficial bacteria- breaking down organics and helping to make them more available for plant growth. 

That being said, the stuff DOES grow aquatic and riparian plants and grasses quite well, in our experience! Yet, I would not refer to them specifically as "aquatic plant substrates." They're not being released to challenge or replace the well-established aquatic plant soils out there. They're not even intended to be compared to them!

Remember, our substrates are intended to start out life as "terrestrial" materials, gradually being inundated as we bring on the "wet season." And because of the clay and sediment content of these substrates, you'll see some turbidity or cloudiness in the water. Like, for weeks.  It won't immediately be crystal-clear- just like in Nature. That won't excite a typically planted aquarium lover, for sure. And no, we haven't done CEC testing with our substrates...It's likely that in some future, some enthusiastic and curious scientist/hobbyist might just do that, of course!

Takeaway: These substrates, because of their unique composition, will create highly cloudy water if you flood it immediately before a "terrestrial" phase. It will take weeks of submersion before you achieve that sort of crystal clarity which we love so much. 

I can't stress it often enough: With our emphasis on the "wholistic" application of our substrate, our focus is on the "big picture"- not specifically aquatic plant growth. Yet, hobbyists being hobbyists, I'm sure that they will evaluate them based upon this ability, so I felt that I should at least address this topic at this juncture.

And the whole thing about "soupy" water, with some turbidity and even a bit of cloudiness to it, is part of the game. It's also very similar to the conditions you see in recently flooded forest floors and meadows.

A whole part of the use of different substrate materials borders on the same mindset we embrace with botanical-style blackwater aquariums in general: The acceptance of natural aquatic systems as they really appear- not as we would like them to appear.

It's tough to stomach this stuff sometimes. It goes against the way we look at stuff as hobbyists. It goes agains the "norms" in a big way...I mean, why would you knowingly put stuff in your aquarium which makes it look less like this?

And more like this?

Well, because it's more like what Nature really looks like.

In many aquatic systems, you'll not only see the turbidity caused by sediments and mud, you'll see a lot of "humus" and coverage created by decomposing grasses and tangles of submerged terrestrial plant roots.

Algal mats which arise from these decomposing materials trees form an important food source and grazing area for many fishes.

And the fine particulate matter which accumulates in the sediment layer is used for sustenance by a huge variety of organisms, some which feed directly on it, and others which filter it from the water or accessing it in the sediments that result. These allochthonous materials support a diverse food chain that's almost entirely based on our old friend, detritus!

The idea of a substrate forming a dynamic basis for an underwater habitat of diverse life forms is a fundamental difference as compared to approaches that we've embraced in decades past. We're pretty excited to see many hobbyists running with this idea, going with mixes of different terrestrial materials in and on the substrate to more realistically represent Natural habitats in their aquariums. 

It's an exciting shift in thinking and tactics!

It's something that I keep coming back to, because the idea of utilizing botanical materials in your aquarium substrate keeps tantalizing me with its performance and potential benefits. 

I've worked with this stuff for a long time, and I'm super excited about this approach.

As I've obsessively reported to you, I recently ran a small tank in my office for the sole purpose of doing damn near the entire substrate with leaves and twigs- sort of like in nature. There was less than approximately 0.25"/0.635cm of sand in there. That was the whole "scape." What we in the reef world call a "no scape." 

Leaves and a shoal of Parachierdon simulans. 

Nothing else.

And the interesting thing about this tank is that it is one of the most chemically stable, low-maintenance tanks I've ever worked with. It held a TDS of 12 and a pH of 6.2 pretty much from day one of it's operation. It cycled in about 5-6 days. Ammonia was barely detectible. Nitrite peaked at about 0.25mg/L in approximately 3 days. 

This was not the first time I'd seen this.

Now, the point of this piece is not to drop a big old "humble brag" about some  tank I ran. The point is to show what I think is an interesting "thing" I've noticed about this tank and others which embraced a "substrate-centric" approach. And approach that uses sedimented substrates, a mix off leaves or other crushed-up botanicals, and some bacterial inoculation..

The results were always the same:

Stability and ease of function.

I am frequently quite astounded how quickly new tanks can go from dry to "broken in" in a week or so. And not just "broken in" (ie; "cycled")- like, stable. I don't usually do this, but I tested all basic parameters every day for the first 3 weeks of the tank's existence, just to kind of see what would happen. in a couple of leaf litter/sediment only tanks I set up, and the results were similar. 

The interesting thing about a tank like this is that it relies on leaves in a way that I have rarely done before. Yet, I had complete confidence that it could work just fine. I'm not some "visionary" here- I'm just a guy who's played with blackwater/botanical-style aquariums for a long time and has developed a certain degree of comfort with them. Many of you are in the same position.

What goes on in an aquarium with botanicals- or leaves, in this instance as the total  "substrate" or "hardscape", as the case may be, is that they become the basis for biological activity in the tank. As we have discussed a million times here, as botanicals break down, they recruit bacteria, fungi, and other organisms on their surfaces.

Mix it up. Play with sediments, crushed leaves, broken bits of botanicals..All sorts of natural "stuff" which would previously have been considered "dirty" and "bad for long term maintenance" in almost anyone's book.

Open your mind up to accept the look and function- and the "aesthetic challenges" of using non-traditional materials in your substrates. 

It'll excite you. Challenge you. And it will expand your horizons in the botanical-style aquarium world.

Stay observant. Stay creative. Stay excited. Stay resourceful. Stay unabashed...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


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