# Converting% Ratios in Fertilizers to Ppm



## mrtank50 (6 Jan 2021)

Hello friends

The% w% rates in Tropica specialized fertilizer (green) fertilizer are as follows.

It is given as 5 ml per 50 liters.

When I use 5 ml for a 50 lt aquarium, I wonder about the ppm values, not the% values.
If there are friends who can help in the calculation and know the ppm values, can they help.


N 1.34%
P 0.1%
Mg 0.39%
K 1.03%
S 0.91%
Fe 0.069%
Mn 0.039%
B 0.004%
Cu 0.006%
Mo 0.002%
Zn 0.002%
Cl 0.5%


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## Zeus. (6 Jan 2021)

Hi and welcome to the forums ,








So just divide the values above by 6 then multiple by 5
This is taken from the  IFC aquarium Fert calculator that will help esp if planning to make you own ferts as well.

Also worth bearing in mind is TSN is ammonium/urea based for its source of nitrogen, so in getting the [NO3] ppm above we have assumed all the N is converted to NO3, which is not the case as some ammonium/urea will be taken up direct by the plants. We dont see this as an issue as we are just comparing the relative amounts of [N] or [NO3] per week and having them all as [N] or [NO3] makes sense so we could compare the different ferts on the market

Hope it helps

Zeus


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## dw1305 (6 Jan 2021)

Hi all,


mrtank50 said:


> It is given as 5 ml per 50 liters.


That makes it really easy,* the percentage on the bottle is the same as the ppm of each nutrient supplied*, because the various dilutions are all factors of 10 and cancel one another out.


Zeus. said:


> TSN is ammonium/urea based for its source of nitrogen, so in getting the [NO3] ppm above we have assumed all the N is converted to NO3


Yes, so we have nitrogen (N) and we want to convert that to a nitrate (NO3-) value, bearing in mind @Zeus.'s comments. We need to know the percentage of N in NO3, and to do this we need to know the Relative Molecular Mass (RMM) of NO3- and Atomic Mass (RAM) of oxygen (O) and nitrogen (N). In this case "16" for oxygen and "14" for nitrogen so we have 14 + (3 * 16) = 62 and then we can divide 62/14 = 4.43 and then multiply 1.34 * 4.43 = 5.93 ppm NO3 in 50 litre.

*Calculation bit*
You don't need this bit anymore, but along with the RAM values of the elements, these are the underpinnings of the IFC Aquarium Fert. calculator.

The spreadsheet is incredibly useful because it <"automates the whole process">, and makes <"value for money comparisons"> etc much more accessible, where you have a less straight forward calculation.


mrtank50 said:


> N 1.34%
> P 0.1%
> Mg 0.39%
> K 1.03% ..........


I'll go through the calculation for potassium (K), but exactly the same process applies to each of the other nutrients.

You have 5 mL of TSN with 1.03% K, first we need to convert 1.03% to a decimal, so that equates to (5 * 0.0103) and *0.0515 g of K*.

At this point we have to assume that we are dealing with water, rather than a a dilute solution, and that 1 mL weigh 1 gram, and that ppm is equivalent to milligrams / litre or  micrograms / gram, so we have added 51.5 mg of K to 50 litres of water <"and mg / L is the same unit as ppm">.

That means we have 51.5 / 50  = 1.03 ppm K.

To check divide 1.24 by 6 (0.207) and multiply 0.207 by 5 and you should get ~ 1.03

& another one for luck,

Magnesium (Mg) this time: 5 * 0.0039 = 0.0195 and 19.5 / 50 =  0.39 ppm Mg

cheers Darrel


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## Nikola (7 Jan 2021)

Hi,
@Zeus. I'm confused with data which You got from that calculator.
If you compare it with rotalla butterfly calculator for "result of my dose" its different. Which one is true here?


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## dw1305 (7 Jan 2021)

Hi all,


Nikola said:


> If you compare it with rotalla butterfly calculator for "result of my dose" its different. Which one is true here?


They are both right and both the same. You can always check using the calculation method in <"the earlier post">.

It is just that the IFC calculator has rounded the value to two decimal places and expressed phosphorus (P) as phosphate (PO4---) and nitrogen as nitrate (NO3-).


ElementRotalaIFCMg0.4680.47K1.2361.24

I hope that makes sense. 

Actually when @Hanuman & @fablau were creating the IFC master file, they cross-referenced the IFC and Rotala Butterfly databases (@fablau now looks after the <"Rotala Butterfly"> nutrient calculator) and found a couple of errors,  which have now been corrected.

cheers Darrel


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## Nikola (7 Jan 2021)

Okay, that is clear for me. But what about N?
Here is 7.12ppm and on rotalla is 1.6? Big difference

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## dw1305 (7 Jan 2021)

Hi all,


Nikola said:


> But what about N?
> Here is 7.12ppm and on rotalla is 1.6? Big difference


It is just the way the values are quoted. One is as *nitrogen (N)* and the the other is as *nitrate (NO3-)*. 

Nitrogen is, unsurprisingly, *100% N*, but *NO3 is only 14/62 = 22.6% N*  (The other 78.4% of NO3 is the three oxygen (O) atoms) and *100/22.6 = 4.43*


dw1305 said:


> Yes, so we have nitrogen (N) and we want to convert that to a nitrate (NO3-) value, bearing in mind @Zeus.'s comments. We need to know the percentage of N in NO3, and to do this we need to know the Relative Molecular Mass (RMM) of NO3- and Atomic Mass (RAM) of oxygen (O) and nitrogen (N). In this case "16" for oxygen and "14" for nitrogen so we have 14 + (3 * 16) = 62 and then we can divide 62/14 = 4.43 and then multiply 1.34 * 4.43 = 5.93 ppm NO3 in 50 litre.


So if you multiply *1.61 ppm N by 4.43 you get .......... 7.13 ppm NO3.*

cheers Darrel


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## Nikola (7 Jan 2021)

Thanks a lot for explaining, wasnt reading carefully your previous post.
This is eyes opening for me, I was thinking that with adding N in aquarium we actually add that amount of NO3.



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## Hanuman (8 Jan 2021)

dw1305 said:


> It is just that the IFC calculator has rounded the value to two decimal places and expressed phosphorus (P) as phosphate (PO4---) and nitrogen as nitrate (NO3-).
> 
> 
> ElementRotalaIFCMg0.4680.47K1.2361.24


@Nikola
I have pushed the decimal... Magic... it's the same now. 🧙‍♀️





Nikola said:


> Okay, that is clear for me. But what about N?
> Here is 7.12ppm and on rotalla is 1.6? Big difference


Our expert @dw1305 has explained it brilliantly so here is just a screenshot from a hidden sheet (one of the brains of the calculator. Yes it has several  brains) in the calculator that illustrates what he said.




Element/compounds calculations are derived from 2 things: information provided by fert manufacturer and the periodic table of elements.


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## Nikola (8 Jan 2021)

Hi @Hanuman, thanks for the reply. It was already clear for me that small difference is due rounding decimal numbers.
The part which Dave explained about relation between N and NO3 I didn't know but now everything make sence.
Cheers 

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## Hanuman (8 Jan 2021)

The reason we did not include N but only NO3 for the compared fertilizers in the user sheets was to make it simple and because mostly everyone refers to NO3 and not N. This said when you create your own fert in the calculator we provide both N and NO3 for each compound that is chosen for completeness.


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## Nikola (8 Jan 2021)

Well that what you did is great! Especially for newbie like I am.
I was already trying to keep my NO3 levels low and now I know that I didn't doo a good job cause I was adding a lot more N than I suppose to cause didn't know relation between those two at all. 


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## Nikola (8 Jan 2021)

@dw1305 this very interesting thread with loads of good info, will need some time to digest everything there.

I awas doing EI couple times and always had stunting my plants. Last time I wanted to exclude ferts from CO2, light and ferts triangle so I dosed again EI for one week and stunted aromatica completely.

By returning to my routine everything is back to normal, very high constant CO2 and high light with low (not as low as I wanted lol ) NO3.

Still I'm twiking with phosphate, as I understand phosphate affect uptake of NO3 and some other nutrients so will experiment a little more with it. 

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## Zeus. (8 Jan 2021)

I find the more I read, the more I find I need to read more. Then when I try to find answers to questions some of the answers are only best theory's or what folk have come to accept as the truth. Keeping an open mind can be very helpful IMO.


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## dw1305 (8 Jan 2021)

Hi all, 


Zeus. said:


> I find the more I read, the more I find I need to read more. Then when I try to find answers to questions some of the answers are only best theory's or what folk have come to accept as the truth. Keeping an open mind can be very helpful


That is the truth, understanding how all the <"moving bits"> line up is <"incredibly difficult">, and if anyone tells you <"they fully understand the processes"> that occur in the tank, or that theirs is the only way, they are probably mistaken. 


Nikola said:


> I awas doing EI couple times and always had stunting my plants. Last time I wanted to exclude ferts from CO2, light and ferts triangle so I dosed again EI for one week and stunted aromatica completely.


I'm not <"a CO2"> or <"EI user">, so I only have low tech experience, but it was the multitude of possibilities (in the  triangle of interacting factors) that led to me to the <"Duckweed Index">, initially using <"_Lemna minor">, _but now using <"_Limnobium laevigatum_">.

A floating plant takes both <"CO2 availability"> and <"light intensity"> out of the equation, so any growth abnormalities are likely to be caused by <"mineral deficiency or availability">. 

cheers Darrel


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## Nikola (8 Jan 2021)

Thanks a lot @dw1305,
By the way I like your approach to aquarium hoby, there are lot of your topic answers here on forum which I adopted in my way of putting dices together. 

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## dw1305 (8 Jan 2021)

Hi all,


Nikola said:


> By the way I like your approach to aquarium hobby


Thank you, I'll be honest a lot of it developed over time because I'm <"not a very good fish-keeper">, or <"very conscientious"> at tank maintenance, and like to follow the <"path of least resistance">.

This has partially been because I have tanks in places where <"I can't easily maintain them"> regularly, and I'm sometimes away with work for <"extended time periods">.

I don't really care about aesthetics, or aquascaping. Personally I admire <"a really vibrant tank">, but I have neither the patience nor the skills to create one.  (Aquascape by @Roland <"Tank for good morning">).





cheers Darrel


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## mrtank50 (10 Jan 2021)

Friends, thank you all for your answer and help.


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