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Does test kit detect the nitrate in a KNO3 solution?

lakshen99

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Hi, i just made my own nitrate fert using KNO3. Using rotalabutterfly, I measured 17.12 grams of the powder into a 350ml container. Each 5ml dose will give me 5ppm. However when i tested that solution for nitrates, Im getting a reading of 0. Does anybody know why?
 

Nick potts

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It will depend on the test kit you use, but I believe they mostly don't actually test for the nitrate directly, they convert nitrate into nitrite and then measure that.

You will also see the consensus on this forum is that most hobby test kits are not reliable anyway :)
 

lakshen99

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It will depend on the test kit you use, but I believe they mostly don't actually test for the nitrate directly, they convert nitrate into nitrite and then measure that.

You will also see the consensus on this forum is that most hobby test kits are not reliable anyway :)
hmm im actually using a test strip that also has a nitrite option but that doesn't show anything either. Im not looking for precise readings but wouldn't a concentrated solution have at least a high reading
 

dw1305

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Hi all,
they convert nitrate into nitrite and then measure that.
They do, they reduce NO3- to NO2- using <"cadmium (Cd) or vanadium (V)">.
........ but wouldn't a concentrated solution have at least a high reading
It should do.
You will also see the consensus on this forum is that most hobby test kits are not reliable anyway
Nitrate is particularly problematic. The only way that the test kit could be working would be if the salt used wasn't KNO3.

cheers Darrel
 

Zeus.

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I measured 17.12 grams of the powder into a 350ml container. Each 5ml dose will give me 5ppm.
I take it you have a 30 Litre tank ? which should yield a 5ppm NO3 with you regime. Test kits work - if you was adding 5ml to 30 litres of RO water IMO/IME it would work fine, however when you test your tank water it a 'broth' of many things which interact and some may affect the way your test kit works. Hence the rational behind not testing.

Trust your maths and you added 5ppm NO3, however unless you use RO water there will also be some NO3 in the tap water also. Unless your after inducing a NO3 deficiency for leaf colour just dose in abundance
 
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Zeus.

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As I read it, it appears that @lakshen99 tested his stock solution of KNO3 and his test kit couldn;t find the nitrate in that either.

Shows how reliable the test kit is then o_O. I used a test kit on a test solution with RO water and a little KNO3 and it worked fine
 

GHNelson

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Hi, i just made my own nitrate fert using KNO3. Using rotalabutterfly, I measured 17.12 grams of the powder into a 350ml container. Each 5ml dose will give me 5ppm. However when i tested that solution for nitrates, Im getting a reading of 0. Does anybody know why?
Containers are easily mixed up....especially if not marked up on both the lid and the bottom half of the vessel.
Your KNO3 could be another fertilizer...very similar in colour texture.....KNO3 has a blue cheesy smell to it I've read in the below article by Clive.
hoggie
 

lakshen99

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KNO3 has a blue cheesy smell to it I've read in the below article by Clive.
hmm blue cheesy smell in its dry powder form? tbh i've never smelt blue cheese before but I do know that it stinks. I smelt mine and i dont get any strong smell at all. Its almost scentless.
 

lakshen99

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On the topic of smelling ferts XD, what should monopotassium phosphate and Potassium sulphate smell like? How about the way it looks? MY KH2PO4 grains look like the way table salt would look like whereas the K2SO4 looks like baby powder though not as soft.
 

lakshen99

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KNO3 is a good fertiliser because it has ~60% nitrate and 40% K, so you get a lot of usable N/O per gram of fert
I saw this while reading @GHNelson. My KNO3 is agricultural grade and this is its "Nutrient Contents: Nitrate-N: 13.7% Potassium (K2O): 46.3% (K: 38.5%)". This is wayy different that what was quoted. Also in what Clive said, Kno3 tends to clump. Mine does a little so that looks good
Edit: i realised N is nitrogen at 13.7%. Nitrate probably a typo by seller.
 

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John q

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KNO3 has a blue cheesy smell to it I've read in the below article by Clive.
Stop... wait a minute.. just smelt all my ferts and no detectable smell from any of them. You can't accurately determine chemical makeup by the smell, unless it's C9H13N 🤩
 
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lakshen99

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I asked different sellers about what should KNO3 smell like. They all have said it should be odorless as well.
 

GHNelson

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