# PO4 - Consumption/Relation With N/K/FE



## Paulo Soares (1 Sep 2017)

Good morning, 

A tank running since first June 2016. 

Specs: 
100 real liter tank
CO2 Injection 20 to 25 PPM
Fertilization by Tropica Specialised 10 to 12 Pushs a day.
Water change 30% twice a week
Highly Planted with Tropica Pots 1/2 grow of 15 different species.
Led Lighting 4000 lumens, very good filtration, maintenance routines etc etc. bla bla bla.. no need to go further on this 

No signs of any algae since assembling till today. Tank runing perfectly.  All plants looking beautiful except for one. 

The person was doing water tests every sunday since June 2016. In all tests along this months the results were always nearly the same.

NO3 between 10 to 15 Ppm
FE Between 0.4 to  0.6
PO4 - 0.1

So.. this guy decides to boost specificaly PO4 in order to see if some improvement came along with that plant that was not on good shape. A bottle of water and some powder of KH2PO4 and a receipe in order to acomplish 1 PPM for each 10 ML dose. 

So here we go.. (also continuing dosing the Tropica Specialised 10 Push a day) 

*Monday*.. add 10 ml before photoperiod. PO4 measures after photoperiod point to 0.4 PPM. 
*Tuesday*  .. add again 10 ML more before photoperiod. PO4 measures after photoperiod point to 0.4 PPM. 
*Wednesday*.. same 10 ml. Again.. 0.4 PPM 
Bought a new JBL test to measure and compare.. just in case. Ok we still got 0.4 PPM. For god sakes.. could it be of the powder? No matter.. bought a new bag of KH2PO4 and here we go again. (Sounds like Whitesnake..) 

*Thursday* add 20 Ml of the solution. (He tought: "I don´t care let´s see what happens i don´t give a damn.. wf is going on??) Again.. for his surprise dosing the double he achieved 0.6 PPM.. 

"Wow.. " 

*Fryday*.. more 20 ML.. and a final result of 0.6 PPM. 
But now he decide to measure the others to.. and guess what ? FE was almost at 1 PPM. (?)

Concernings:

Why and how this PO4 consumption if it never occured before?
If plants till now never eat this much with the Tropica Specialised and looking very very beautiful what is going on in the tank since this guy decides to add more PO4?
What happen in the relation between PO4 and FE so that since PO4 was added iron increase that much?

One thing is for shure.. the plant still looks the same and did not improve a damn thing. 

So PO4 is out of the question as the other elements. (I guess..)

But this water/elements/chemistry behaviour and this consumption really drives us for many questions.

Any thoughts?

Best regards


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## Daveslaney (1 Sep 2017)

Strange indeed.
My first though would be perticipation of po4 FE,but if this was the case why would the FE raise?
Some substates are said to grab ferts from the water column? but this still dont explaine the raise in FE?


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## Paulo Soares (1 Sep 2017)

Daveslaney said:


> but this still dont explaine the raise in FE?



Nor even the consumption..


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## Zeus. (1 Sep 2017)

Humm...

well you increase PO4 dose so the equilibrium of PO4 in the Water Column (WC) and the AS changes so the AS mops up the extra PO4 so the WC [PO4] remains constant until you increase the PO4 dose to where the AS is saturated. The [Fe] increase may be due to the PO4 having a higher affinity to the AS so therefore Fe stored in the AS is displaced in favour of the PO4 due to it higher ionic bonding.

Complete stab in the dark by me


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## roadmaster (1 Sep 2017)

Maybe bump in Ferrous sulfate by municipal water treatment plant ?
Is said to sometimes be used for phosphate removal in municipal and industrial sewage treatment plants to help prevent eutrophication.


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## Daveslaney (1 Sep 2017)

If you look on reef sites there is a method used for sps corals that uses a low nutritional water column to bring out the best colours and health in the corals.This is based on water bacterial colonys that drastically reduce phosphate and nitrate levels to zero in the water. But this is based on organic carbon dosing.Could this happen in a planted tank?The organic carbon coming from the plants?Or even liquid carbon or co2?


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## ManDrawer (20 Sep 2017)

Did you check if the PO4 salts actually contain PO4? I made a thread about PO4 salts I bought that actually did not contain any PO4 at all.

I'm testing whatever I can when I buy salts, because after my experience I don't trust labels anymore.


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## Paulo Soares (21 Sep 2017)

ManDrawer said:


> Did you check if the PO4 salts actually contain PO4? I made a thread about PO4 salts I bought that actually did not contain any PO4 at all.
> 
> I'm testing whatever I can when I buy salts, because after my experience I don't trust labels anymore.



Morning,
Yes of course we´ve tested 
The salts were bought in "Aquasabi".
We took 10 ML from the solution and tested and yes the JBL reagent turns almost black.
So we did for NO3 turning into a red dark.
So the salts were ok.

So.. at that time we couldn´t figure out how this happens...
The plant was trimmed and for now it seems good. 
He´s still using Tropical Sppecialized and all is doing fine.

Best regards

P.S. Now also using Tropica Premium. 5 Pushs a day


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## tmiravent (21 Sep 2017)

Paulo,
that 'issue' is discussed many topics here in UKAPS and other foruns.
Search engine should delivery lot's of answers.

My advice is take a reading in Diana Walstad book (Ecology of the Planted Aquarium).
It covers nutrient relations, fertilization, etc.

I try to be on the relax side, i learned to don't care too much about the 'prefect' levels...
I watch and make the changes during tank evolution.
If all plants are good (minus one) why change the system? maybe leave that plant for another time...
Sometimes plants don't grow too well in presence of other specific plants, D. Walstad says it can be from *allelopathy...
*
There are many theories, some believe that stuff doesn't exist at all.
Others say that plants are more 'clever' that we thought and are capable of exchanging information, even food!

I try to act more simple, if it doesn't work change it!
Cheers


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## Paulo Soares (21 Sep 2017)

Hello Tiago, 

Exactly what we did. The plant was trimed and now it´s up to her show her grace  

If she wants to of course  

Mother nature has it´s own ways.. 

Big Hug


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