Phytagen P1 should be dosed when necessary (ideally once a week); in such amount as to bring/restore phosphate/phosphorus concentration to the set target value.
Taking anyway into account the fact that 1 ml of PhytaGen P1 in 15 liters of water increases phosphate (PO₄^3-) by 1 mg/l (equal to 0.326 mg/l of Phosphorus).

Choice of the phosphate/phosphorus target value

The target value for Phosphate/Phosphorus is substantially represented by the concentration of Phosphate/Phosphorus consumed by the tank in one week.
Which varies according to 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 Phosphate:

• High VM: 1.5 mg/l of phosphate from PhytaGen P1
• Average VM: 1 mg/l of phosphate from PhytaGen P1
• Low VM: 0.5 mg/l of phosphate from PhytaGen P1

The dosage of PhytaGen P1 must therefore be performed keeping into account the phosphate target chosen for the specific tank (depending on the VM of the same) and carried out with the aim of bringing the concentration of phosphate back to the target previously set.

The dosage must take into account the fact that 1 ml of PhytaGen P1 in 15 liters of water increases phosphate (PO₄^3-) by 1 mg/l (equal to 0.326 mg/l of Phosphorus).

Dosing procedure

The correct weekly dosing procedure is as follows:

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

• From the measured Phosphate value, the desired target value, and the volume of water replaced, calculate (using our online calculator) the volume of PhytaGen P1 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 P1 obtained from the calculator

Once the composition of the tank and the growth rate of the plants is stable, 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 phosphate (which is however recommended ).

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

• High VM: 1.5 mg/l of PhytaGen P1 phosphate per week
• Average VM: 1 mg/l of PhytaGen P1 phosphate per week
• Low VM: 0.5 mg / l of PhytaGen P1 phosphate per week

Based on these estimated consumption, the dosage can be assumed without the need to measure the phosphate; 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 plant amount and growth rate (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 phosphate by 1 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 phosphate around 1 mg/l.

In order to obtain the best results it is also very important to dose the phosphorus in a balanced manner compared to nitrogen (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 P1 should therefore be used in conjunction with PhytaGen N1 according to the respective directions of use.
In particular, the combined use of PhytaGen N1 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.

Phosphorus is the 6th most present element in quantity within plant tissues. This is followed by Carbon, Oxygen, Hydrogen, Nitrogen and Potassium. 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 (albeit with some difficulty for Carbon ), Phosphorus (such as Nitrogen and Potassium) must necessarily come from less easily available sources. Due to the large quantity needed by plants, Phosphorus is defined, together with Nitrogen and Potassium, as a Macroelement.

Role of Phosphorus in plant nutrition

Inside the plant, Phosphorus is basically used for energetic purposes (production, storage and transport).

But it is also an essential nutrient; both as part of structural compounds and as a catalyst in key biochemical reactions. It plays a central role in photosynthesis (production of sugars and starches) and in respiration (production of energy from the oxidation of sugars and starches).

It is also a fundamental component of DNA (the "memory block" of all living things) and RNA (the compound that "reads" the genetic code of DNA to regulate protein synthesis and genetic transfer).
The structures of both DNA and RNA are in fact held together by phosphorus bonds.

Phosphorus is therefore essential for cell division and the development of new tissues.

Symptoms of Phosphorus deficiency

Phosphorus is a mobile element.
That is, the plant manages to move it from the old areas to the new ones to try to make up for its deficiency and allow the plant to continue growing as long as it can.

In phosphorus deficiency, old leaves appear with damaged and yellowed areas especially along the edges.
At the same time, however, the whole plant slows down its growth.

The old leaves then gradually die and fall, while the growth becomes progressively slower.
As the phosphorus is transferred back from the older leaves to the younger leaves, the growth stops and if the deficiency lasts the plant dies.

Genesys of PhytaGen P1

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 phosphorus concentration in aquarium?

This question can not have a unequivocal answer.
As we already detailed in the tab regarding the usage, this depends mainly on the amount of plants and their growth rate.

The latter being influenced by various factors, such as the nutritional status (mainly the amount of dissolved CO₂) and light irradiation.

In general, the suggestion is to follow the suggested dosages, keeping phosphorus concentrations ranging from about 0.16 to about 0.33 mg/l (equivalent in terms of phosphate to 0.5 mg/l for low vegetal metabolism aquariums and up to 1.5 mg/l for high vegetal metabolism aquariums) and not exceeding 0.65 mg/l (equivalent to 2 mg/l of phosphate) for a single administration.

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

Does phosphorus causes algae?

The idea that phosphorus may cause algae in the aquariums arose from an article (Control of algae in planted aquariums) of two Canadian aquarists: Conlin and Sears.
In their article they reported the results of some experiments conducted by them in their aquariums.

In these experiments the two authors noted how by eliminating the phosphorus from the water (but leaving it confined in the substrate) it was possible to maintain a good growth of the plants while obtaining a reduction or disappearance of algae.

Where or when water was supplied with phosphorus, algal growth resumed.

In general, in these cases we must always consider the validity of the Liebig law.
That is the fact that the growth of the vegetals (plants and algae) is limited by the lack even one of the indispensable elements (whatever).

When this element is then administered again, the growth of the vegetals (plants and algae), no longer being limited, immediately resumes.

Therefore limiting an essential element (such as the aforementioned phosphorus) in water, it will be possible to limit the growth of those plants that obtain their nourishment exclusively from water.
Algae and floating and epiphytic plants essentially.

On the other hand, the growth of those plants that are able to obtain that nutrient by the roots from the substrate will not be compromised.

But this is valid for each of the essential elements for plants.
Phosphorus is still an excellent candidate from this point of view because it is an element (macroelement) that is used in fair quantities and because it is an element that, with appropriate strategies, is able to contain quite well in the substrate in an insoluble form, avoiding that it disperses in water.

It must be said, however, that in plant aquariums commonly found today among enthusiasts, with many plants growing rapidly and which are then pruned and replanted often (having to replenish the root system every time), it is not possible to maintain rapid growth and optimal only with the nutrients in the substrate and must provide quite substantial doses of all the essential elements directly in water.

Hence the theory/strategy of Conlin and Sears has had a short life, showing itself not entirely correct in motivations/conclusions and impracticable in the implementation; as a matter of fact already surpassed after about ten years from its formulation.

The conclusion is therefore: No; Phosphorus does not cause algae.
Just as algae are not caused by any of the essential mineral elements in particular; being an algal proliferation to be sought essentially in the presence of organic material in the tank, in a non-optimal growth of the higher plants present (bad competition with algae) and in the imbalance between nutrients (see Redfield Ratio).