The nitrogen cycle made easy

Aquarium hobbyist guides (and the trade!) make the nitrogen cycle and the famous "nitrite spike" the obsession of every aquarist setting up a new aquarium, trash tank, or pond. But is the reality as simple as the seller of "magic vials" claims?

 

The famous "nitrite spike"

Every aquarist knows this: the nitrogen cycle is important in an aquarium.

 

If they don’t know it, they quickly learn it from the pet shop seller who reminds them not to introduce fish into a newly set-up aquarium without waiting 3 to 4 weeks for the “nitrite spike” to pass, thanks to the bacteria developing in the filter.

 

That is the dogma.

It allows the seller to convince you to buy the magic vial of “water conditioner”, the bacterial strain straight from the lab and its fridge, and of course the little chemist’s kit to measure this famous “spike.”

But, as always, things are more nuanced, but above all simpler for those who want a small peaceful aquatic corner of nature, not a chemical analysis lab!

On analyses and parameters, read "When too many analyses kill the aquarium"

 

The principle of the nitrogen cycle in an aquarium

When I created in 2011 the concept of natural low-tech aquarium keeping, it was above all out of love for laziness and weariness of spending more time serving technology than watching my little aquatic world. It was the discoveries made during the trash tank adventure, started in 2004, that made me understand that all this was often more useful to the merchant than to the fish!

Nitrogen exists in all living things.
It is even the mark of the living.

Living beings therefore emit nitrogen in all their waste: droppings, urine, tissue renewal (dead leaves, molts), carcass. Immediately, this waste decomposes.

Bacteria and molds transform this nitrogen into ammonia. And that is toxic and plants do not consume it all, especially in a very young aquarium.

Then, bacteria transform this ammonia into nitrites. This is also very toxic.

Finally, bacteria transform these nitrites into nitrates, which are less toxic and consumed... by plants. And the circle is closed: the nitrogen of the living returns to the living!

 

The manual (and the seller) will tell you that each step is carried out by a different species of specialized bacteria: Nitrosomas transform ammonia into nitrites, then hand over to Nitrobacter who make nitrates. All this is nestled in the heart of the filter masses.

So, at the start of an aquarium, the Nitrosomas must have time to make nitrites (toxic) so that the next ones transform all this into nitrates (less toxic). And so, while waiting for the second to appear, there is a moment when nitrites are not broken down and this produces the famous “nitrite spike.” It is estimated that it takes 3 to 4 weeks for nitrites to allow Nitrobacter to appear. Then, the cycle is triggered and, with Nitrobacter permanently in place, nitrites no longer have time to appear: they are eaten within a minute!

Except that’s in the manual.

 

The nitrogen cycle in reality... and in nature

In reality, new bacteria are constantly being discovered that also do this work, alongside those in the manual. And there are probably even more.

This makes the little vial of bacteria from the merchant quite pointless, as it contains only a single cloned strain of a single species supposed to trigger the famous cycle.

In fact, it is observed that this dreaded “nitrite spike” does not always occur, and not always in a very marked way.

For example, if you introduce invertebrates (or the water that contained them) right at the start of the aquarium, you are no longer introducing a single species of bacteria, but thousands (or more). Each dropping or molt of each species holds, like a treasure, a library (a "microbiota") of incalculable diversity!
Instead of a laboratory experiment, you then make an ultra-complex and teeming biodiversity work. Not only will you have all the bacteria that ensure the nitrogen cycle even before a nitrite spike occurs, but you will also trigger all the other cycles of life (phosphorus, potassium, various trace elements...).

 

And above all, none of this absolutely needs the presence of a filter, these bacteria working perfectly comfortably in the sand (each grain is covered!) or on all surfaces (leaves, glass, rocks, etc.). It is even thought that some live freely in the water, without any particular support.

In short, just like in any natural body of water!

The filter and nitrates in the aquarium

The filter allows nitrates to form, not to reduce their amount by even a single gram.

Just like this microbiota does very well without it.

It is the plants, and only they, that will consume (and thus eliminate) nitrates, if they have enough light to live.

 

Nature is varied and complex and, unlike laboratory conditions, there are always several species that perform the same function, each ready to take over if the others weaken.

That is why biodiversity ensures cycles in a much more robust way.

A Starter Box that applies these principles to the aquarium or pond

The ZollaBox Starter is based on this principle. It does not matter if the fish end up eating the invertebrates it contains: it is their varied and countless microbiota that will be installed permanently, each microbial species, known or unknown, taking its place in the ecosystem.

 

Refills for this ZollaBox allow renewing this seeding each year (which I recommend), like a booster shot.

Once again. Letting nature do its work with its complexity, instead of vainly trying to control every parameter, is simpler and above all much more restful!

 

Over-intervening is always a bad sign, because no single action on one of the countless parameters of an ecosystem can do anything but unbalance it. Which will allow the merchant to recommend the next vial, then the next one!

 

Using nature as an ally

The artificial demands constant effort to hold up a deeply unstable balance.

The natural balances itself, provided it is given all possible diversity, from which it will draw its own solutions.

As the periphyton of your ecosystem forms, the balance will become more and more robust (see here: "What is periphyton?").

 

And then, the nitrogen cycle becomes a spectacle to watch calmly from the armchair, not a “problem” that requires intervention.