# PO4 / NO3 High Consumption



## Paulo Soares (15 Nov 2016)

Good afternoon, 
I´m not going to be very extensive cause i assume most of us know the "EI" assumptions and guideness. 
For those who doens´t take a look here: 

http://www.ukaps.org/index.php?page=dosing-with-dry-salts

So if we have a maximum plant Uptake of:

Nitrate (NO3) 20ppm per week
Phosphate (PO4) 3ppm per week

*Please can anyone be kind to explain how a tank can consume at list 3 PPM of PO4 and more than 10 PPM of Nitrate a day? 
Quite astonishing isn´t it?*
(Be advised is not a testing issue)

Take this Ei receipe for an example.  



Could be any salt precipitation? 
Would like to ear some opinions. 

Thanks in advance.


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## EdwinK (15 Nov 2016)

Lets assume that tests are super accurate and plants are not consuming any ferts. Then PO4 could be absorbed by AS Amazonia, NO3 by denitrification process.


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## Paulo Soares (15 Nov 2016)

Hello Ed
I have Tropica Plant Growth and the soil. 

What is NO4? 
How can a four month old tank be in a process of denitrification? Quite impossible i believe. 

I do have a friend that is going through the same as i concerning consumption. Is tank is almost 6 months.


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## EdwinK (15 Nov 2016)

Paulo Soares said:


> What is NO4



NO3, typing error. 



Paulo Soares said:


> How can a four month old tank be in a process of denitrification? Quite impossible i believe.



You asked for a possible causes. I'm sorry but I'm not a biochemist and can't tell if it is possible or not.


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## EdwinK (15 Nov 2016)

Here is the link to ADA product catalog - http://www.adana.co.jp/en/contents/support/pdf/
Check out Part1, page 50/51, figure C. Pay attention what AS does to phosphate concentration.


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## Paulo Soares (15 Nov 2016)

Many thanks dear friend

Downloading and reading. 

let´s see if we can get an answer on this. 

Big hug


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## dw1305 (15 Nov 2016)

Hi all,





Paulo Soares said:


> Could be any salt precipitation?





EdwinK said:


> Then PO4 could be absorbed by AS Amazonia,


Either precipitation or anion exchange would do for the phosphorus (P). 

If you had alkaline water you could keep adding large amounts of PO4---, the total reservoir of soluble phosphorus would rise, but the amount of soluble (plant available) PO4--- would remain fairly low. This is the situation in a lot of rivers etc in the UK, where measurable available phosphorus is fairly low, but the additional phosphorus reserve would take thousands of years to deplete back to the pre-industrial level.

Pretty much all nitrate compounds are soluble, and mono-valent anions are lightly bound, so neither ion exchange, or precipitation as an insoluble compound, helps with nitrate. 

The NO3 may have been out-gassed, via anaerobic denitrification, but it is much more likely to have been incorporated into plant tissue.

It would depend upon the plants, and their access to other nutrients (including CO2), but my suspicion would be that the 20ppm NO3 limit is too small by an order of magnitude (it is only ~5ppm N).

cheers Darrel


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## Paulo Soares (15 Nov 2016)

Ok guys many many thanks. 
Yesterday i did a full water change (hope it was not a mistake) .. i´ll be measuring the days ahead and let´s see if it gets established.

Big HUg


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## Paulo Soares (16 Nov 2016)

dw1305 said:


> The NO3 may have been out-gassed, via anaerobic denitrification, but it is much more likely to have been incorporated into plant tissue.



You´re right  
After several readings i agree with you.

Let´s see in the future whemn this phenomenon stops what to do. 

Big hug


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## dw1305 (16 Nov 2016)

Hi all, 
In <"Plants and nitrogen"> it has figures for nitrogen uptake by _Spirodela polyrrhiza & Pistia stratiotes. _They are slightly complicated by the plants preference for ammonium (NH4+), but indicate that _Pistia _can remove higher amounts of nitrogen than the 20ppm NO3 per week quoted. 

Behrends (2010) <"Use of aquatic plants for removal of nitrate-nitrogen in subsurface flow constructed wetlands"> found that _Cyperus haspan _could remove 56mg ppm of NO3 in 96 hours.

cheers Darrel


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## alto (16 Nov 2016)

dw1305 said:


> found that _Cyperus haspan _could remove 56mg ppm of NO3 in 96 hours


how much plant mass in what volume of water?


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## dw1305 (16 Nov 2016)

Hi all,





alto said:


> how much plant mass in what volume of water?


It was 4 litres of nutrient solution in 8 litre containers. There are pictures of the DOE in the linked pdf document.

cheers Darrel


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## alto (16 Nov 2016)

thanks - I obviously didn't scroll far enough


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