"Cyclical clarity" and other botanical quirks...

Ever noticed that aquariums seem to go in "cycles", and display certain "quirks" in their function?

For example, some tanks will enjoy periods of time where the fish and plants are actively growing, the water is crystal clear, unwanted algal growth is minimal, and everything seems to be "spot on."

And then, inexplicably, after months or years, the tank may not look quite as good for several weeks, only to rebound to it's former glory with minimal intervention on your part.

I think we've experienced this in planted tanks. 

And more recently, I've experienced certain "quirks" with blackwater/brackish botanical-stye aquariums. 

In particular, once of the things I've noticed is that the water will take on a bit of "cloudiness" from time to time, almost as if it's been "dosed" with some sort of materials which make it a bit turbid- even with excellent husbandry techniques.

And in a sense, it has. I think there are a few explanations, once of which is that there is a gradual, yet cumulative decomposition of organic materials from within the botanicals themselves; maybe it's substances within the wood or botanicals you're playing with, like lignin, etc., which seeps into the water column as the materials break down, exposing new layers of their tissues to the aquatic environment.

And then it goes away just as mysteriously as it comes...

And of course, as a lifelong aquarium hobbyist, when you see stuff like cloudiness, you first start looking at overall water quality, feeding, and husbandry technique. I am a fanatic water quality guy, being a reefer,  and am a devoted tester and water exchange person. Yes, is it possible that my feeding or technique could have caused this? Maybe, but not likely. My tanks are environmentally stable, have little to no detectable nitrate, barely detectable phosphate, and receive regular water exchanges.

And I stock lightly.

However, arrogance aside- it IS Possible, right?

The other would be that there is a sort of "bacterial bloom", which is certainly possible. Interestingly, I utilize mangrove wood in both my home blackwater and brackish water aquariums at this time and I'm of the belief that this is a beautiful type of wood, but it's very "dirty" from a standpoint of materials contained within the tissues of the wood. Both of my tanks experienced an initial "haziness", which I hadn't seen to the same extent with other botanical systems I've played with which utilized different types of wood.

Coincidence? Perhaps.

I mean, every botanical tank seems to get a certain "patina" to it (one of my blackwater-enthusiast friends calls it "flavor") which impacts the overall appearance of the system. And we do throw seed pods, leaves and other stuff into our tanks- a perfect "cocktail" for unusual water conditions, huh?

Ultimately, the cloudiness thing just sort of goes away, yielding that sparkling brown clarity that we love. Sure, some activated carbon and stuff like Poly Filter help, but I think the biggest  factor is time.

The other random factor in our version of the botanical-style brackish aquarium is the use of very rich, mud-influenced soils in the composition of the substrate we play with. I think some of the material leaches into the water column on occasion. Add this to the equation, and with the occasional burrowing activities of the snails we employ, and with the significant water movement provided by electronic pumps, and this is another factor which can affect water clarity.

And perhaps it's also the including of the mangroves themselves, and the epiphytic organisms which live on and among their roots and propagule structures?

The other quirks we all experience from time to time is the accumulation and dissipation of biofilms and occasional biocover on our botanicals. I know many hobbyists (myself included) which have run tanks with minimal biofilm over their botanicals at almost every phase of the tanks existence.  

Others have experienced the (scary to the uninitiated) burst of biofilm which accompanies the addition of botanicals to a new aquarium. In our community, we take the waxing and waning of biofilms in our tanks as a sort of "right of passage", and have come to expect and tolerate the stuff. It was, and still is- a big part of the mental shift hobbyists have to make when transitioning to this type of aquarium from a more "conventional" one.

Accepting that decomposition, change, and the transformations of hardscape materials by fungal and bacterial action are simply part of the game, and as you're tank matures and becomes more biodiverse, it "evolves" to some extent.

Oh, but that biofilm and turf algae and fungal growth really gets to some people!

Left alone, it almost always seems to dissipate in just a few weeks. And occasionally, you'll see a covering of biofilm or turf algae crop up on botanicals which have been submerged for some period of time, seemingly without reason. 

These occasional "outbursts" by the biofilms may disappear as quickly and mysteriously as they appear, without any apparent correlation. Or do they? Well, there must be SOME explanation! 

And of course, as we know, everything occurs in nature (and our tanks) for a reason...And the searching for answers and trying to figure out the "hows and whys" of our unique aquariums has been a real delight for me.

Nature- and out tanks...are ruled by cycles. Seasonal? Biological? All types. Something we haven't thought a lot about in aquarium keeping (except for the nitrogen cycle, of course). 

Cycles and quirks.

The undeniable "quirkiness" of a blackwater/brackish, botanical-style system is one of the most enjoyable facets of this type of approach. It's a constant evolution and a tremendous thing to witness firsthand.

Yes, they're filled with quirks. However, botanical-style aquariums are filled with a certain something..A "mystery", a "vibe", an operational "structure", which separates them from what we have come to expect as "normal" for aquariums over the decades...

And that "something" is what keeps many of us coming back for more- quirks and all!

Stay excited. Stay devoted. Stay experimental. Stay creative. Stay patient...

And Stay Wet.


Scott Fellman

Tannin nAquatics 


Scott Fellman
Scott Fellman


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