I am happy to see that you know a lot about all kinds of interactions in the planted tank and inside the plants. And especially how finely balanced they are. But knowing all these details still does not make you capable of setting up a clean tank every time. Do not think I am dismissing what you know and said about CO2 fluctuations, Rubisco, variations of the uptake, and so on.

What follows below is an explanation why I think that all that information is actually secondary – only important if you know how to run the tank “properly” as I like to call it;

So I realized that the goal is not to remove organics but to have them PROCESSED PROPERLY by the microorganisms. Which means one single thing – the biofilter that these microorganisms are must be in a prime state at all times. That is how I came up with the expressions “properly established biofilter” and “properly established planted tank”.

I setup a new tank and dumped a thick layer of mulm in it. 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 should have a situation in which every point of the tank is gobbling up organics. Little did I know that 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):

https://photos.app.goo.gl/1QDornEEgZ6Q9w9M9

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” – when 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:

https://photos.app.goo.gl/6vATi65e6BBvbJBl2

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 biofilter and plant health
After that experiment 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:

https://photos.app.goo.gl/Yyb4btzuQZRxLMBWA

Making it work
I hope you follow what I write. It is a long story but I am trying to explain to you 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.

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 thing. 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. But that 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 seldom discussed. And when they are discussed it is usually on a very superficial level.

That same study also shows that biofilters in different aquariums are actually comprised by different species of microorganisms. So you can not say “Aha, this here mix of microorganims is The One!”. And there is more – in all aquariums the developed biofilter is the same functionally, but not as 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.

So…

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.