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Converting% Ratios in Fertilizers to Ppm

mrtank50

Member
Joined
6 Jan 2021
Messages
69
Location
Türkiye
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%
 
Hi and welcome to the forums :D,

1609928889487.png

1609929256165.png

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
 
Hi all,
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.
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.
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
 
Last edited:
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?
Untitled.png
 
Hi all,
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-).

ElementRotalaIFC
Mg0.4680.47
K1.2361.24

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

Sent from my STK-L21 using Tapatalk
 
Hi all,
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
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
 
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.



Sent from my STK-L21 using Tapatalk
 
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-).

ElementRotalaIFC
Mg0.4680.47
K1.2361.24
@Nikola
I have pushed the decimal... Magic... it's the same now. 🧙‍♀️
Screen Shot 2021-01-08 at 13.50.27.jpg

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 :p brains) in the calculator that illustrates what he said.
Screen Shot 2021-01-08 at 13.50.07.jpg


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

Sent from my STK-L21 using Tapatalk
 
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.


Sent from my STK-L21 using Tapatalk
 
@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.

Sent from my STK-L21 using Tapatalk
 
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.
 
Hi all,
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.
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
 
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.

Sent from my STK-L21 using Tapatalk
 
Hi all,
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">).

31639727_166567228541927_1116961726669514876_n-jpg.jpg


cheers Darrel
 
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