The x-y-z you see on bottles usually refers to N-P-K-Fe-trace concentration in %.
So for pure KNO3 you will have 14-0-39. But in the hobby most people report N as NO3 which is 61%.
Watch out, most terrestrial fertilizers also use NH4NO3 urea and others. Depending on local regulations this may be detailed or not.
You also asked about using something other than KNO3... You sure can do it but. You have to be a lot more careful. Urea is not the only replacement, NH4NO3, NH3 also work.
Just be sure to have low pH values when dosing, <6.5, break the dose into daily, 2x 3x per day.
The problem with them(also urea) is that they are toxic to fish, shrimps and plants in high enough conc. And the toxic level is quite low. When the bio filter is mature it should quickly process these substances into NO3, making them safer. You can experiment and see how much how fast the filter is able to remove NH3 and NO2 from the water.
Another option would be to run a parallel tank where you enrich water with NH3 and give it time to be converted to NO3. Then simply use that water to fertilize.
Before you give up on NO3, also look at hydroponics shops, meat conservation shops, general chemical providers. You might also find a farmer who is willing to order some for you. It all depends on the regulations in your country, some countries love to require a license to buy a hammer or a screwdriver, because you can hurt or kill a man with it. Oh well, always respect the laws of your country of residence.
No problem. I will go step by step and by the end of it you will be able to calculate the N % from the other molecules on your own.
To simplify things a little, every chemical element has an average atomic mass. When the elements join together they form a molecule with an mass equal to the sum of the elements.
In order to work with common units of mass we use a lot of molecules 6.022*10^23, which represents a mole. Put simply a mole is a unit that tells you the number of things, no need to concern yourself anymore with it at this stage. Just defining it as it will come up later.
From chemistry we know the average atomic weight of all the elements (easy to find out, Wikipedia, Google, etc).
Let's work trough an example:
Element - - - Atomic weight(g/mol)
To find the molar mass of KNO3 make the sum of the components.
We want to find out what percentage of KNO3 is N.
So in 100g KNO3 you have 13.8g N
What about NO3?
So in 100g KNO3 you have 61.3g NO3
Now, a few observations :
1. Obviously you cannot measure NO3 alone. You weight the substance(KNO3) and produce the theoretical weight of each ion.
2. There are certain rules that dictate what happens when/if a molecule is dissolved in water. For example KNO3 will separate into K+ and NO3-. There will be no free O or N because water. Is not strong enough to break them apart.
3. Still we know plants take up NO3 directly and are able to use the N from NO3 so it is not wrong to calculate the N conc.
I have never heard of this NO3 of 61% calculation. I would like to know the source of the NO3 these people are speaking of. Aquariumfertilizer.com carries potassium nitrate with a 14.5% nitrates. You could order calcium nitrate instead for a 15% nitrate content, which would also be more likely to be allowed to be shipped into China. There is a reason for this relatively low percentage of nitrates. Although nitrates are necessary for all life as it is the primary building block of proteins, too high a percentage causes physiological difficulties and pressures on the organism.Sorry I'm still new at this but 14-0-39= N 14%, P 0%, K 39%? how do I calculate to NO3 61%. I'm still confused about the calculation. I'm living in China so it will be hard for be to get GLA orr Nilocg to send me ferts. Basically have to go find the fertz myself at a garden store.
Another thing I'm worried about is not getting KNO3 which I need but getting Urea instead.
Here's the KNO3 I'm planning to get. Pls ignore the Chinese but it states water soluble 13.5-0-46-1. what do you think?
I have never heard of this NO3 of 61% calculation. I would like to know the source of the NO3 these people are speaking of. Aquariumfertilizer.com carries potassium nitrate with a 14.5% nitrates. You could order calcium nitrate instead for a 15% nitrate content, which would also be more likely to be allowed to be shipped into China. There is a reason for this relatively low percentage of nitrates. Although nitrates are necessary for all life as it is the primary building block of proteins, too high a percentage causes physiological difficulties and pressures on the organism.