Phytagen N1 should be dosed when necessary (ideally once a week); in such amount as to bring/restore nitrate/nitrogen concentration to the set target value.
The dosage of PhytaGen N1, has to be done taking into account the fact that 1 ml of PhytaGen N1 in 15 liters of water increases Nitrogen by a quantity equivalent to 10 mg/l of Nitrate (NO₃^-) (2.259 mg/l of nitrogen).

Choice of the nitrate/nitrogen target value

The target value for Nitrate/Nitrogen is substantially represented by the concentration of Nitrate/Nitrogen consumed by the tank in one week.
Which varies depending on the quantity of plants present in the tank and their growth rate (influenced by the amount of light, CO₂ and other nutrients).
Later we will summarize this with the term "Vegetal Metabolism" (abbreviated as VM) and we will exemplify distinguishing between:

• High VM: high nutrient consumption; due to the presence of many rapidly growing plants.
• Average VM: average nutrient consumption; due to a reasonable presence of plants and/or their average rapid growth
• low VM: low nutrient consumption; due to the presence of a few plants and/or a low growth rate.

Obviously all the intermediate gradations remain possible.
Depending on the aforementioned VM, alxyon recommends that you use the following target values ​​for nitrate:

• High VM: 15 mg/l of nitrate from PhytaGen N1
• Average VM: 10 mg/l of nitrate from PhytaGen N1
• Low VM: 5 mg/l of nitrate from PhytaGen N1

The dosage of PhytaGen N1 must therefore be performed keeping into account the nitrate target chosen for the specific tank (depending on the VM of the same) and carried out with the aim of bringing the concentration of nitrate back to the target previously set.

The dosage must take into account the fact that 1 ml of PhytaGen N1 in 15 liters of water increases nitrate (NO₃^-) by a quantity equivalent to 10 mg/l (equal to 2.259 mg/l of nitrogen).

In particular, the amount of nitrogen supplied is distributed as follows:
• 9.3 mg / l of ion nitrate (NO₃^-)
• 0.2 mg / l of ammonium (NH₄⁺).

This part of ammonium is equivalent to 0.7 mg/l of NO₃^-.

Dosing procedure

The correct weekly dosing procedure is as follows:

• Measure, before the water change, the concentration of Nitrate in the tank (in order to evaluate the weekly consumption).

• From the measured Nitrate value, the desired target value, and the volume of water replaced, calculate (using our online calculator) the volume of PhytaGen N1 needed for reaching the afore mentioned target value.

• Perform the recommended water change (20-25% of the total).

• Introduce the new water remineralized with the salt mix PhytaGen S1 Planta or PhytaGen S2 Planta.

• Wait until the salts have completely dissolved and the water has returned perfectly clear.

• Dose the amount of PhytaGen N1 obtained from the calculator

Once the composition of the tank and the speed of growth of the vegetables have settled, it is possible to assume with a good approximation that the consumption remains constant and the quantity already known can be measured without having to necessarily measure the concentration of the nitrate (which is however recommended ).

By way of example, based on our experience, we report the following possible consumption:

• High VM: 15 mg/l of PhytaGen N1 nitrate per week
• Average VM: 10 mg/l of PhytaGen N1 nitrate per week
• Low VM: 5 mg/l of PhytaGen N1 nitrate per week

Based on these estimated consumption, the dosage can be assumed without the need to measure the nitrate; But, as mentioned, alxyon's recommendation is to proceed as detailed in the points above.

For example:
In general, for an aquarium with a good presence and vegetal growth (medium MV), the dosage is recommended for the first week at a rate of 6.7 ml per 100 liters of aquarium water.
This dose increases the nitrate at 10 mg/l.
From the following week onwards, on the other hand, it will be dosed according to the consumption of the tank; or what is necessary to bring/maintain the concentration of nitrate around 10 mg/l.
In order to obtain the best results it is also very important to dose the nitrogen in a balanced manner compared to the phosphorus (see "Redfield Ratio" in the technical notes).

In particular, a ratio of about 7: 1 between nitrogen and phosphorus should be maintained.
Equivalent also to maintain a weight ratio between nitrate (NO₃^-) and phosphate (PO₄^3-) of about 10: 1.

Based on this principle PhytaGen N1 should therefore be used in conjunction with PhytaGen P1 according to the respective directions of use.
In particular, the combined use of PhytaGen P1 at the same dosage guarantees the combined nitrogen and phosphorus supplementation in the correct N: P ratio of 7: 1 (ratio NO₃^-: PO₄^3- of 10: 1)

Below you can find a dosage calculator, which can also be used on mobile phones.
Just select the relevant product (S1, M1, M2, N1, P1) from the tabs at the top, enter the required data and the program will calculate the quantity of product to be dosed.

Nitrogen is, after Carbon, Oxygen and Hydrogen, the most present element within plant tissues.

But, while Oxygen, Hydrogen and Carbon do not pose major supply problems as aquatic plants are able to obtain them from the gases present in the atmosphere or from the water in which they live, Nitrogen must necessarily come from sources less readily available.

Nitrogen, due to the large amount needed by plants, is defined, together with Potassium and Phosphorus, as a "Macroelement".

Nitrogen has a peculiar and unique characteristic in relation to plant nutrition:

• It can be absorbed in both its ionic forms; As anion nitrate (negative ion NO₃^-) and as ammonium cation (positive ion NH₄⁺).

• It can also be absorbed in a non-ionic form (for example in the form of amino acid).
In any case, however, all the processes inside the plant that require nitrogen necessarily pass through ammonium.

Once absorbed, therefore, all the nitrogen of any form is rapidly transformed into ammonium and with this the amino acids and proteins essential for its metabolism are readily manufactured.
It is therefore understandable how plants have a predilection for the ammonium forms of nitrogen, as the energy expenditure for their use is lower (they must not be converted into ammonium as happens for nitrates).

Note how, depending on the type of nitrogen compound absorbed, the plant changes its internal chemistry and even the chemistry of the water that surrounds it.
This is because by absorbing the NH₄⁺ cation the plant will release a Hydrogen ion (H⁺), while by absorbing a NO₃^- anion the plant will release a hydroxyl anion (OH^-).
Therefore in the first case there will be a lowering of the pH of the culture water, while in the second case there will be an increase in the pH of the same.

Given the large amount of nitrogen absorbed, this effect is generally not negligible and is commonly used in hydroponic cultivation systems and in micropropagation containers to keep the pH of the nutrient solution at the optimal value.

The latter therefore, in the aforementioned environments, is also maintained by providing the cultivated vegetables with a nutritional solution with a correct ratio between Nitric Nitrogen and Ammonic Nitrogen.

In planted aquariums this is much less important, due to the regular administration of CO₂ which, in addition to providing the carbon necessary for plant metabolism, keeps the pH at the correct values, preventing it from rising excessively.

In general, however, beyond the consequences on the pH of the culture water, the best nitrogen nutrition for a vegetable is that which combines the different forms of nitrogen.

The ratio between nitric and ammonium nitrogen is also a function of the individual preferences of the plant species housed.

In a complex environment such as the ecosystem of an aquarium, where there are not only plants but also animals (often delicate), it is also necessary to take into account the chemical and biological stability of the same as well as the potential toxicity of the ammonium ion (due to its possible conversion to Ammonia).

Role of Nitrogen in plant nutrition

Nitrogen is essential for the structure of the plant itself, as the proteins that compose it are made up of amino acids of which nitrogen is an essential component.
All the enzymes that allow the major biochemical processes to occur within plants are also proteins.

For example, the synthesis of proteins within plants takes place through ammonia compounds which, if not directly absorbed, can also be derived from the reduction of nitrates.
Some enzymes (such as nitrate reductase which is an enzyme that also contains molybdenum) are involved in the transformation from nitric nitrogen (oxidized) to ammonia nitrogen (reduced).

Nitrogen also plays a fundamental role in cellular respiration and photosynthesis, carried out thanks to protein compounds that intervene in the Calvin cycle and in thylakoids.

It also promotes cell multiplication and intervenes in the formation of protoplasm, the apical sites of rapid cell division and growth.

Also not to be overlooked is the fact that it is a necessary component of several vitamins (biotin, thiamin, niacin and riboflavin) and nucleic acids (DNA and RNA).

Symptoms of Nitrogen deficiency

As it is easy to imagine from the list of biological functions in which nitrogen plays a fundamental role, its deficiency is able to quickly block the growth of the plant.

Nitrogen is a mobile element within the plant; therefore its deficiency initially manifests itself on the older leaves.
These turn yellow quickly, first showing a pale green color and then a uniform and widespread chlorosis (yellowing).
The young leaves generally manage to remain green (although paler) thanks to the nitrogen translocated from the old leaves, but they gradually shrink.

At the same time the growth of the plant slows down, as does the branching. When the shortage continues, the plant gradually loses its leaves starting from the oldest ones and finally dies.

Genesys of PhytaGen N1

This formula represents the culmination of several years of studies related to:

• The nutritional needs of aquatic plant organisms
• The chemistry in water of the elements and compounds involved.

Our search for the ideal formulation can be considered divided into two distinct and consequential phases:

1 - Analysis in / of natural habitats In the initial phase we first built our references, basing ourselves (as well as on the review of the scarce scientific literature available) on many dozens of analyzes carried out in various natural biotopes in Europe, Asia and America, through the use of the most modern and accurate instruments such as spectrophotometers and X-ray mass spectrometers (EDX).
These analyzes, carried out both on the plants and on the water of the selected biotopes, allowed:
a) The evaluation of the mineral composition of many of the best known species of aquarium plants coming directly from their natural habitat, in relation to their visible state of health
b) The assessment of the mineral balance of the source waters, in relation to the visible health of the ecosystem and the plants present.

The subsequent statistical analysis of the accumulated data, with analysis of variance (ANOVA) and of the correlation between the data relating to the plants and those relating to the waters they belong to, allowed to extrapolate an optimal average composition valid for approximately all plant species currently known in aquarium and the corresponding ionic balance ideal for culture water.

These are important data to start from and to deal with in the next phase.

2 - Analysis in culture Starting from the references obtained in the first phase of analysis of the ideal parameters in natural habitats, we then continued with the second phase of study and tests aimed at obtaining and maintaining the aforementioned ideal parameters in an artificial and closed environment (our cultivation in hydroponics, submersion and micropropagation).

The results obtained were finally evaluated and verified both visually and again by analyzing the nutritional solutions and plant tissues as already described for the first phase, comparing them to our references.

The product of this work is represented by mineral supplements that fully guarantee the nutritional needs of aquatic plants and allow the perfect growth of even the most demanding species in the conditions highlighted in the directions of use.

C:N:P relationship and Redfield Ratio

Maintaining the correct ratio between Carbon, Nitrogen and Phosphorus (N: P ratio) is very important for plant nutrition but also for maintaining the correct chemical and biological balance of aquatic ecosystems.

Much research has been done on this and the theories formulated are well substantiated and work quite well in practice.

The so-called "Redfield Ratio" and the theory that follows from it was developed in 1934 by oceanographer Alfred Redfield.
He noticed that the ratio between the quantities of Carbon, Nitrogen and Phosphorus constituting the healthy oceanic phytoplankton, as well as of the Nitrogen and Phosphorus in the waters of healthy seas remained close to a well defined value.

In fact, his observations are valid not only for oceanic phytoplankton and not only for seawater chemistry but also for freshwater chemistry, for the related phytoplankton and also for higher aquatic plants (see further on about the studies and analyzes carried out by alxyon).

More generally, with the term "Redfield Ratio" we can express the theory according to which, in natural aquatic ecosystems, plants in good health maintain within them the optimal ratio between Carbon, Nitrogen and Phosphorus.

The optimal C: N: P ratio found by Redfield is about 106: 16: 1 in molar terms, or about 41.1: 7.23: 1 when expressed by weight (e.g. in mg or mg/l). Equivalent also to maintaining a weight ratio between Carbon, Nitrate (NO₃^-) and Phosphate (PO₄^3-) of about 13.67 / 10.645 / 1

Similarly for the waters, staying in a neighborhood of the aforementioned N:P ratio there is a low probability of eutrophication with consequent uncontrolled algal development.
Therefore, referring to waters, (omitting at the moment Carbon) and considering Nitrogen and Phosphorus in the form of Nitrate and Phosphate, all this can be represented in the following graph:


When you get out of the equilibrium zone (yellow zone) by changing the ratio in favor of phosphorus (blue zone) you can easily have proliferation of blue-green algae (cyanobacteria).

When you come out of the equilibrium zone (yellow zone) by changing the ratio in favor of nitrogen (green zone), green algae can proliferate.

Of course, we must be careful not only to maintain the correct relationships, but also not to overdo the absolute quantities.
Thus in a normal aquarium, problems may arise, despite the N: P ratio being correct, even if the quantities of N and P are exaggerated (see information on quantities in the section on directions for use and in the F.A.Q.).

In any case, the "Redfield Ratio" gives an excellent indication and its practical application in the aquarium generally gives excellent results.
It is obvious from what has been said that to monitor and maintain the correct values ​​and ratios, it is necessary to rely on regular water chemistry tests.

With regard to fresh water and the studies and analyzes carried out by us on 73 species of aquatic plants in their natural habitats and in cultivation, they differ little from Redfield's studies, doing it to a statistically insignificant extent and therefore not altering its correctness.

The average optimal ratio between Nitrogen and Phosphorus (N: P ratio) found by us for aquatic plants was in fact found to be, expressed in weight, around 7.5: 1. In terms of Nitrate and Phosphate (NO₃^-: PO₄^3- ratio) this optimal average ratio by weight is equivalent to about 10.8 / 1 and in molar terms to 16.585 / 1

 
What is the optimal Nitrogen concentration in aquarium?

This question can not have a unequivocal answer.
As we already detailed in the tab regarding the usage, this depends on the plant mass present and its growth rate.

The effect is influenced by various factors, such as nutritional status and light irradiation.

In general, the suggestion is to follow the dosages of nitrate concentrations from about 5 mg/l for a low VM (vegetal metabolism) up to about 15 mg/l for aquaria with a very high VM, and in any case without exceeding 20 mg/l for a single administration.

All of this, always trying to keep a good ratio to Phosphorus, as detailed in the technical notes, regarding the description of the "Redfield Ratio".

Which forms of Nitrogen should be used?

As mentioned, Nitrogen is available in several forms.
Among the most common, we can find:

• Nitrates
• Ammonium
• Urea
• Amino Acids, Peptides, Proteins
• Other ammonium compounds

As said in general, plants prefer Nitrogen in reduced form (Ammonium), since they can use it directly for the internal production of aminoacids and proteins.
By doing so, they do not need to waste energy for converting Nitrates by reducing them to Ammonium.

However, it is not possible to supply Nitrogen to plants exclusively in the form of Ammonium.
This is due to the fact that it is necessary to maintain a correct internal equilibrium, and because a massive dosage in aquarium of ammonia nitrogen would create imbalances and probable algal explosions.

When in the tank there are not only plants, but also delicate aquatic organisms (fish, invertebrates, etc.), the Ammonium can only be supplied in quantities sufficiently low to protect them from any toxicity.

Urea is used as a reduced nitrogen because in water it splits freeing Ammonium.
Because of this it brings with it the toxicity problems related to the administration of Inorganic Ammonium.
Moreover, Urea, in order to be used inside the plants, must also be converted into Ammonium and to do this a nickel-based enzyme is necessary.
At this point the nickel, although required in very low quantities, should be supplied from the outside.

Furthermore, Urea, as an organic compound, provides a major stimulus to algal growth, so it is preferable not to use it in the aquarium.

Considerations analogous to those regarding Urea are valid for the Nitrogen coming from Amino Acids.
Amino acids do not carry the problems related to ammonium / ammonia toxicity but, like Urea, do promote algal growth quite a lot.

As mentioned, PhytaGen N1 provides Nitrogen in the two inorganic oxidized forms, with the oxidized form (Nitrate) to a predominant extent by virtue of its very low toxicity and with a small amount of reduced Nitrogen (Ammonium) such as not to be harmful, in the normal dosage ranges of the product, even to the most delicate organisms, but such as to be a stimulus to the development of the plants and to the nitrifying bacterial flora (from which the stability of the aquarium ecosystem depends intimately).