# KNO3 Questions?



## DaveFish (Jul 19, 2011)

So My KNO3 is 13.5%-NO3 and 46.2%-K (no chloride) My first question is," If my KNO3 is mostly K why does everyone say that KNO3 releases mainly NO3 and has a side-effect of releasing some K?" I need to know what is happening to the K in the reaction.
Second question," If there is no chloride and the amounts don't add up to 100% total, then what other substance is the manufacturer using in the admixture?"

(Multi-K bag by Haifa Chemicals Ltd.)


----------



## DaveFish (Jul 19, 2011)

Okay so I have the GG bag _"Greenhouse-Grade." I read the table showing the specs. I guess some K is K2O, doesn't show percent on bag. That percentage is making up the difference adding up close to 100%


----------



## Left C (Jun 14, 2005)

In the US, many times the amount of K in a fertilizer is expressed as K2O even though there is no K2O in the product. If your KNO3 was 100% pure, it would be approximately 38.67% K and 61.33% NO3. When you search for phosphate (PO4) as in KH2PO4 fertilizer, it is screwy too. You will find it typically expressed as the weight % of phosphorus pentoxide (P2O5) in the fertilizer materials. Alternatively it can be expressed as weight % of P.

Seachem has several examples on their site. They speak of "archaic fertilizer laws.' Below are just three examples. http://www.seachem.com/Products/Planted.html

Equilibrium Guaranteed Analysis
Soluble Potassium (K20) 23.0%
Calcium (Ca) 8.06%
Magnesium (Mg) 2.41%
Soluble Iron (Fe) 0.11%
Soluble Manganese (Mn) 0.06%

Derived from: potassium sulfate, calcium sulfate, magnesium sulfate, ferric sulfate, manganese sulfate.

Elemental potassium is present at a concentration of 195,000 ppm (19.5%). Archaic fertilizer laws force us to list potassium in terms of equivalence to a material that is not present (K2O) rather than the more scientificaly sound method of simple elemental equivalence.

-------------------------------------------------------------

Flourish Potassium Guaranteed Analysis
Soluble Potassium (K2O) 05.8%

Derived from: Potassium Sulfate (K2SO4)

Elemental potassium is present at a concentration of 50,000 ppm (e.g 5%). Archaic fertilizer laws require us to list potassium in terms of equivalence to a material that is not present (K2O) rather than the more scientificaly sound method of simple elemental equivalence.

--------------------------------------------------------------

Flourish Phosphorus Guaranteed Analysis
Total Phosphate (P2O5) 0.3%
Soluble Potash (K2O) 0.2%

Derived from: Potassium Phosphate Dibasic (KH2PO4)


----------



## DaveFish (Jul 19, 2011)

Okay so When you compare K's equivalence to K2O the percentage goes up in this case. Maybe why my bag seems to have so much K and very little NO3?

And maybe my NO3 is being expressed in weight not volume that is why it only shows 13.5%? or the other way around? I'm still confused as to why it releases more NO3 if my bag shows these numbers.
BELOW.

13.5%-NO3 46.2%-K

Thanks for the help.


----------



## Left C (Jun 14, 2005)

Are either of these products the KNO3 that you purchased?
Multi-K® GG 13.5-0-46.2 Greenhouse-grade potassium nitrate
Multi-K® pHast 13.5-0-46.2 Low-pH potassium nitrate

FROM: http://www.haifachem.com/download/files/Multi-K benefits.pdf
Multi-K is composed of 100% plant macro-nutrients. It comprises of potassium cation (K+) and nitrate anion (NO3-), with N-P2O5-K2O analysis of 13-0-46.
(13% N are equivalent to 62% NO3- and 46% K2O are equivalent to 38% K+, summing up to 100% KNO3).

Notice that I told you the following which basically agrees with their description:


> ... If your KNO3 was 100% pure, it would be approximately 38.67% K and 61.33% NO3. ...


From the same link as above, it says that there is no ammonium in it. Its nitrogen source is nitrate. Excess ammonium can lead to algal issues and possible harm to your fish, shrimp and snails.
* Multi-K provides easily available nitrogen. Nitrate is the most available form of nitrogen for plant uptake.
* Multi-K is non-toxic to roots. Unlike ammonium, the nitrate-nitrogen in Multi-K does not destroy plant roots at elevated soil temperatures.


----------



## DaveFish (Jul 19, 2011)

I have the Multi-k GG. Okay now that makes perfect sense, I just needed to know what the explanation was behind the percentages. Now you've sparked my curiosity. What is the conversion formula for the K+ to K2O and N to NO3- ratios. If 13%-N = 62%-NO3 how do you determine this relationship?

Thanks for all the help.


----------



## Left C (Jun 14, 2005)

DaveFish said:


> I have the Multi-k GG. Okay now that makes perfect sense, I just needed to know what the explanation was behind the percentages. Now you've sparked my curiosity. What is the conversion formula for the K+ to K2O and N to NO3- ratios.
> 
> Thanks for all the help.


This is one of the things to dig into on my "to do list," except it has been on this list for years and I have yet to set down and play with it.

I know that some of the conversions are based on atomic weights. See below. Not sure on the N-NO3 type conversions, the K to K2O conversions and the P to P2O5 conversions..



DaveFish said:


> If 13%-N = 62%-NO3 how do you determine this relationship?


We use the atomic weights found in the periodic table of elements. Note that I rounded them off to the nearest whole integer. This can have slight differences in the actual amounts, but for this example, it is fine.

K x 1 = 39 
N x 1 = 14
O x 3 = 16 x 3 = 48

Total = 39 + 14 + 48 = 101
NO3 = 14 + 48 = 62

Now we convert to percentages.

% of K = 39 ÷ 101 x 100 = 38.6%
% of N = 14 ÷ 101 x 100 = 13.9%
% of O = 48 ÷ 101 x 100 = 47.5%
% of NO3 = 62 ÷ 101 x 100 = 61.4%
KNO3 = % of K + % of N + % of O = 38.6% + 13.9% + 47.5% = 100%
or
KNO3 = % of K + % of NO3 = 38.6% + 61.4% = 100%

Does this part make sense?


----------



## Zapins (Jul 28, 2004)

It may also be that the % they give are based on the fact that KNO3 is hygroscopic (absorbs water from the air). Some of the extra material might just be water.


----------



## DaveFish (Jul 19, 2011)

Yeah that makes perfect sense. Thanks for taking the time to explain this. I am going to print off the periodic table and figure out the percentages of my other fertilizers. 

Yeah I would really like to know the conversion formulas. I'll have to look into it and see if I can figure it out, now that I have some understanding and direction as to how...

Thanks again.


----------



## Left C (Jun 14, 2005)

One of the better fertilizer calculators is by a forum member named wet. His petaphile calculator will do a ton of things including EI and PPS-Pro calculations, results of a dose, amount needed to reach a certain amount, dosing dry, dosing solutions, using grams, teaspoons, milliliters and many, many more things. It will calculate and graph the buildup of a substance over time given X amount of water changed. Gosh, a bunch of things! Check it out.

In other words, wet has already used the periodic table for you.


----------



## DaveFish (Jul 19, 2011)

That petalphile calculator is super nice. I love the ability to see the build up over time with the graph. Thanks for the recommendation.


----------

