I am happy to see that you know a lot about all kinds of interactions in the planted tank and inside the plants themselves. And especially how finely balanced and dynamic everything is. But knowing all those details still does not let you set up a clean tank every time. I am not dismissing knowledge about CO2 fluctuations, Rubisco, variations of the uptake, effects of Nitrogen availability on the plant’s ability to kick metabolism into high gear, and so on. Such intricate details are only a support for the foundation of the living aquarium – the interactions between the living creatures in it. The primary goal is to provide an environment for life forms to interact in a certain way. All the atomic/molecular interactions adapt to that.

Below I describe how I came to the view that all that information is actually secondary – only important if you know how to run the tank “properly” as I like to call it;

The missing piece
In 2009 I discovered a lot of plant physiology information strictly related to the planted tank on a Russian website. The website is the end of all discussions – there are articles about every single aspect and every single topic is supported with multiple scientific references. There are more than 130 pages on the website and practically all of them are packed with information. Supported with references to scientific articles. When I was referred to the website within 5 minutes of reading it I went crazy with joy. At that point I had spent almost 10 years obsessing about the issues in planted tanks – especially how they can be setup properly repeatedly and predictably. I thought that all my questions will be answered and I will be able to setup clean and stable tanks every single time.

That was not so. Not even close. What happened over and over was the same old thing – I’d setup tanks and some will be fine but others won’t. At one point I was part of a rare fish import business and we had about 70 holding tanks. You could see that some were different – either very stable or easily destablized. So we could say that my observations are based on numerous tanks. Plus many years in the hobby – more than 4 decades.

I could never find a good reason why all tanks seem to not act the same every time. Tanks sitting side by side on the same shelf were different despite the same care they received. All the cool information about chemicals, uptakes, and fine variations of what not during the day meant nothing if I was stuck being unable to setup a tank predictably. And it does not take much to know that every other person is in the same boat. Even aquarium maintenance businesses have cases in which a tank acts “abnormal” despite standard procedures. The accepted rule is that clean tanks take effort and time to maintain clean. I do not consider that right. Anything in life is that way – if it takes too much effort something is not being done right. There is a better, more efficient way to do anything.

The biofilter
Since I’ve been in that hobby very long (42 years as of year 2020) when I see a possible answer to a problem I can easily refer to all kinds of past related situations. Apparently I do not know how to focus very well on solving a problem but rather obsess with it. Is that a habit or a result of my hectic work schedule is not important. Slowly I started to realize that over the years there have been many situations in which the biofilter inside the canister filter has had a profound positive or negative effect on the tank. I can describe many such situations. Some seem to make no sense at all – cases in which removing the canister filter actually benefited the tanks.

There was literally no discussion on any planted tank forum regarding the biofilter beyond some very simple basics. The biofilter was in the biomedia, it processed Ammonia, it took about 3 weeks to develop, some medications kind of hurt it – that was literally all the information. At that time everybody’s focus was on lighting, CO2, and fertilizers. It made sense – the mentality was that we were in this hobby because of the plants so we focused on their needs. That is why despite what I had seen I did not think much about my own observations.

Someone I trust told me that the biofilter mainly handles organics. And that the Nitrogen cycle is a small part of the biofilter function – only about 10% of what it does. I do not know if the Nitrogen cycle is considered “organics processing” or “organics processing” refers to breaking down larger organic molecules to their building blocks which later enter the Nitrogen cycle. To this day I do not know what are the actual percentages but at that time organics became my main interest. One reason being that reducing N and P in a planted tank also resulted in an outcome that is not always predictable.

One thing that has come forth again and again all these years is the fact that a process can reach the same end in different ways. In a planted tank the way something happens is more important than reaching the end result. Because the overall state of the tank is completely different depending on how the goal is reached. That is the difference between a tank that constantly needs care and one that is simply joy to watch – because it is truly an independent miniature world.

–> Tank1: A very clean tank. Takes a lot of weekly and daily care to maintain.

–> Tank 2: A clean tank that has been running for a long time. Stays clean, and seems to support itself completely.

Same result – different ways. But Tank 2 is not only stable but also it is definitely the better environment. That is evident by the behavior and health of the living creatures in it.

–> Tank 1: A low organics load (due to regular water changes) Maybe a light fish load + lots of plants.

–> Tank 2: Organics load is definitely higher
. Maybe has a lot of fish + lots of plants.

Same result – both tanks are clean – but different quality.
The second tank has a true tendency to stay clean. Left alone it will not deteriorate for weeks and even months. That can not be said for the first tank.

Normally most people’s planted tanks are maintained clean through water changes and can not be left without maintenance for more than 7 days. Usually by day 4 negative changes start to develop. And it is widely accepted to “shut down” the tank if you can not take care of it for a week or two (going on vacation). That is the reality of the modern planted tank hobby. There is quite a bit of lack of common sense.

Artificial removal of organics
After learning that organics maybe the cause of an aquarium’s unpredictable behavior I started to think of of ways to remove organics from the system.

The first thing I looked for was a way to test for organics – to know how much are present in the tank and if my efforts to remove them work. But in the aquarium hobby there is not a single test that allows you to test for organics. You need to get a professional, expensive test kit that is not easy to use and even contains dangerous chemicals. That situation is truly strange – here we have a hobby that is about living things but the very fundamental part of the system is never closely inspected – the processing of waste.

The problem is that waste – organic molecules – is very reactive. It can attract or release substances depending on different factors – pH, osmotic pressure, addition of certain chemicals, reaching threshold levels of concentration, structure of the waste etc. So the lack of “visiblity” for the state of the waste results in changing the state of the tank in a seemingly random fashion.

As you know – simple practical approaches like frequent water changes or filling the tank with plants don’t really guarantee a clean (organics-free) tank. Yes, the tank stays clean but ONLY after it goes through the usual period of all kinds of issues and ONLY if the maintenance never stops.

Without a way to track the amount of organics I thought that I could judge the progress by indicators like algae presence and stability, water clarity, substrate cleanliness. The first thing to do was to find something that removed organics – a filtration media. In the wastewater treatment industry there are ion exchange resins that are specifically made to remove different kinds of organics. Some aquarium supply companies market them too – for example Seachem’s Purigen, Brightwells OrganitR. I experimented with about 5 different resins. They were placed in a reactor for better reaction conditions. There were obvious results in just 2 days – clearer water, algae growth slowed down or stopped. Here’s a video of the reactor in action:

But all resins load very quickly. On the video above you see the snow white unused resin on the bottom and the light brown color of the resin loaded with organics. Judging by the color change of the resin in the reactor the tank was loaded with organics in the beginning. The very first portion of resin discolored in a matter of hours. But few days later it took almost 1 full day to start to discolor. By that time there was an obvious improvement in the tank’s water clarity and reduction of algae (BBA). All BBA disappeared with the exception of the BBA on the substrate – since the substrate was not stirred in any way the waste lingered there. The results were very promising.

So the conclusion was definite:

If there is a way to keep the sequestration of organics stable the tank will stay extremely clean.

Catastrophic effects of complete removal of organics
Eventually my efforts to remove organics using resins resulted in an almost 100% stripping of all organics from the water. The tank got extremely clean and the water was so clear that looking through 6 ft of water was like looking through air. The BBA on the bottom became very thin and short. Very close to disappearing:

I believed I have solved the problem and the only issue was about maintaining the resins on a regular basis. But that amazing clear water/clean tank state lasted about 36 hours. Then the tank crashed. It started to develop white haze in the morning. That was very bad news and I knew it will progress super fast. The white haze is microorganisms that become suspended in the water when conditions severely deteriorate.

By removing organics I had disturbed the bacteria. I knew the bad signs from previous experiences. And I knew that things will start to go down extremely fast. They did. The white haze got real bad in the afternoon of that same day. Imagine pouring a gallon of milk in the tank. By the next day you could not see anything in the tank. And there was also a starting green tinge – green water along with the suspended microorganisms (the white tinge). The tank could not go back to normal for 3 full months! From previous experiences I knew that the only way to fix that was to let the tank be. No water changes, nothing. Not touching the tank at all. Any water added to the tank to compensate for evaporation lead to a worse green water and haze for about 2 days.

The conclusion from that last observation:
Adding new water to the unstable tank in trouble leads to more trouble – points to the fact that the microorganisms in an aquarium do react to any change we introduce. Water changes, especially big ones, are a huge change. That is the reason most planted tanks do not have a properly developed microbial community – 50% weekly water changes is a serious way to suppress the natural establishment of microorganisms. Especially if tap water is being used for water changes.

During the 3 months he green water and haze randomly alternated, cleared a bit and got bad again. At one point the green water was so dense that you could only see your fingertip pressing the inside of the glass. Nothing else.

After 3 months the magic moment came – I saw a bit of clarification that was stronger than usual. I knew – in 2-3 days the tank will be super clear. And that is exactly what happened.

But I was back to square 1 – removing organics with resins proved to be very risky. The only way that I knew to setup a stable and predictable tank was to load it with plants and fight/wait through a period of instability/unpredictability. Truly back to square 1 – because I knew that some tanks will eventually get clean but others won’t.

Natural processing of organics
Clearly removing all organics from an aquarium is not a good idea. The lesson of the 3 month hazing/green water experience was that you MUST have organics in the tank. You can not just remove them completely and enjoy a clean tank. There must be a balance between the waste production and processing. No brute and complete removal. You must have thriving microorganisms – they process the organics. It’s really as simple as that but that simple truth carries a lot of charge.

So the big revelation was that the goal is to have organics PROCESSED PROPERLY by the microorganisms. In other words the biofilter needs to work properly. Which means one single thing – the biofilter must be in a prime state at all times. The biofilter develops gradually so that means that it needs to be given time and conditions to develop properly. That is how I came up with the expressions “properly established biofilter” and “properly established planted tank”. The time line is anywhere between 6 to 14 months – all tanks are different.

First results using natural processing of organics
I setup a new tank and dumped a thick layer of mulm in it. “Mulm” is the dirt we all syphon from the bottom of the tank when we clean it. I had now understood that that living dirt is something very misunderstood. It is the very thing that keeps the tank clean. Moreover – the microorganisms that are part of the mulm cover every surface of the tank – substrate, decorations, equipment, hoses, plants and fish, and of course – they are in all the surfaces of the external filter (media and walls). Collecting the microorganisms in large numbers is the easiest when you syphon mulm from the bottom of the tank.

Here are pictures: The idea was that if the biofilter eats organics before anything else I will dump it over everything inside the tank and I would create a situation in which every point of the tank is gobbling up organics. Little did I know that simply dumping the “dirty water” in the tank was going to lead to great things. Below are pictures of that tank in the first day of setup. It shows the amount of mulm and the clarity of the water the next day (impossible to really show on a picture). What I saw the very next morning was shocking. The water was so clear that it looked as if it was not there.

Also I did the “white bucket test” – you syphon water from the tank in a white bucket. If it has any kind of tinge of color then there are organics in the water. I was shocked to see that my new tank water looked literally bluish. Not a speck of yellow. It is not possible to take a good picture of that:

One day I compared a white bucket of tap water to a white bucket with water from the tank. There was a tiny difference – but it was a difference between 2 shades of blue!

The white bucket test may be cool but Russian aquarists from the 1950s and before valued a tank’s “old yellow water” as being “alive”. That means that in such tanks the biofilter had developed properly and not only kept the tank clean but also protected the fish from diseases (as the old Russian books state). Meaning that the goal is once again – not to have a completely clean water but to have a system that works as it is naturally meant to work.

The biofilter and plant health
After the rapid overnight cycling I decided to stuff the tank with plants. I got a ton of rare plants. I intentionally bought them from people that I knew grow them in extremely high tech tanks. Huge PAR, CO2, ferts, water changes… What I saw happening in my tank is impossible to describe – it does not fit the common experience and knowledge:

Not a single one of the 22+ species of rare plants ever died. The only way most of them died was because a few species grew faster, got out of the water, and shaded everybody else. All that happened with very low CO2, no fertilizers, no water changes. There were no fish in the tank. The light was low to medium light (70PAR for only 3 hours a day). The new Amazonia supplied a lot of Ammonia and that saved the day someone knowledgeable told me. But there is no way anybody can keep such high tech plants alive for more than a few days in such “mediocre” conditions. Today, 3 years later, the tank is still running. There never, ever, was any algae in it. Only once I introduced a small piece of wood that had a little BGA on it. The algae never spread. It just sat there never growing. Eventually it disappeared. This is the tank today – I like the very wild look and it fits the all-white room very well. The plants are the same plants from 3 years ago:

Following Nature’s ways
Above I described how I started to understand that simplifying the aquarium setup and maintenance practices is the way to go. All the cool details we can find about physiology etc. are only second.

::: Biofilter evolution in the aquarium
Studies (I can send you links) show that the microorganisms that form the biofilter change completely from Day 0, to Day 30, to Day 60. In fact it has been found that the populations on these different days are made of species that are not even related evolutionary. Meaning that an older, well developed biofilter is a very special co-operating structure. For example – not a single species dominates but there is a great variety of species.

You can not interrupt that natural development and expect to have a problem-free tank. Constant biofilter suppression and interruption is exactly what most aquarists do when using fertilizers, water changes, adding/trimming/removing plants. The biofilter has no chance to develop smoothly. Problems are always around the corner. In the last 20 years – since year 2000 – the lack of understanding has been so deep that tank stability and the state of the biofilter are practically never discussed.

::: Biofilters – functionally identical, structurally different
That same study also shows that biofilters in different aquariums are actually comprised by different species of microorganisms. Meaning that there is not a special combination of microorganisms that needs to come together. The study showed that in all aquariums the developed biofilter is the same functionally despite the different mix of microorganism species. Meaning that a well developed filter will process waste very well but the creatures that do that are not the same from one tank to another. All that means one thing – the same thing again – the biofilter must be left to develop properly and not be interrupted. You are literally letting Nature do her thing. As opposed to constantly interrupting.

The above two findings also explain what I found by accident – that dumping a bunch of old “mulm” in a new tank not only cycles it overnight, but also renders it stable and clean. Because you are populating the brand new area with life that has had time to establish and develop. You are making a new tank old in a matter of hours. There is no initial period of issues, need for clean up, maintenance. You can literally not change much water. The biofilter does all the cleaning.


I hope all that was not hard for you to read and follow. I wrote it partly because I will show you a video that will be of much greater interest to you if you knew what it is about. The things I described above are shown working in the video. A severely algae infested tank is rendered beyond clean without any work, water changes, fertilizers, reduction of light. And no, that is not the only tank I have setup and observed to do that once a properly established biofilter is added to it. Today, 3+ weeks after the tank became clean some of the plants have become 3 foot long, and there is a lot of shading going in. Not a speck of algae anywhere. The tank looks as if it was setup 10 minutes ago – just like it looked when it cleared up.

And the coolest but very reasonable thing about using the power of the biofilter (adding mulm): The tank does not need to be new. It can be a tank with ongoing problems. You can clean it without any work. The results will be not just far better than any manual cleanup and special filtration you can do but will also render the tank stable. VERY stable. Think about letting it evaporate 50% or add more light to it or shut off the CO2 or add CO2 or add more fish or reduce the fish. No problems, ever. Sounds like a pipe dream. But it is the reality of a properly established biofilter. Over the years I have had neglected tanks that acted exactly like that. But I never had the mindset to see what was going on in front of my eyes.

Now. I will have to ask you to not share the video with anybody. What will happen is what I have seen many times – intellectual theft. There are people that would claim that was their idea and promote it as such for personal gain and profit. Please respect my trust in you and do not share the video.

(Video is private. Shared only by request.)

Also – that miraculous transformation without any work other than dumping some mulm in the tank hides some important details. But they are not water changes or other such common practices. The details have to do with the big picture. Is the tank actually in a state to support the newly introduced mulm? Is the tank in a state to actually grow plants? Things like that.