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Discussion Starter · #1 ·
I apologize in advance for this long winded post.

But I have to ask……Are all EI fertilizers the same? That is, the same exact ingredients in the same proportion? At the risk of being of total fish nerd, here’s why I ask.

I recently purchased a new API Nitrate test kit. I’ve used these for many years, and understand the importance of vigorous shaking and following the directions precisely. From my tank, old kit reads 80+ppm, new kit reads about 20ppm. Tap water both read zero.

So after searching here I decide to make a reference solution, following Hoppy’s directions http://www.plantedtank.net/forums/11-fertilizers-water-parameters/83545-calibrating-test-kits-non-chemists.html, which are very similar to those on other sites.

Basically ¼ tsp Kno3 to quart of distilled water, then dilute to concentrations of 100ppm, 50ppm, 25pp, etc.

So I set about like a mad scientist (wife was very amused), followed the directions precisely, and was getting pretty curious to see the results. Well, the experiment ended in a thud as all the vials were bright yellow zero Nitrates. Tank water still 80+ or 20ppm depending on the kit.

So I decide to do another test, and add 1 tbs instead of ¼ tsp (12 times as much), and, yep, you guessed it, every vial bright yellow, zero nitrates. Tank water once again 80+ or 20ppm.

So now I am getting kind of nutty, my wife thinks I have lost my mind, and I’m beginning to think there isn’t any no3 at all in my Kno3. So I mix 1 tsp to about ¼ cup of water (really, really strong), and do yet another test…..and lo and behold bright red there actually are some nitrates in there!

So I begin to think how can this be possible? My only conclusion is that Kno3 could be many different concentrations or blends (how much K? how much no3?) depending on who you buy it from. All my EI ferts are from GLA.

Now if that’s true, what effect does this have on EI dosing? If I’m dosing 1 tbs of Kno3, but my Kno3 is completely different than your Kno3…….??? And how do you have any hope of making a reference solution? You see where this could go? (or maybe not and you stopped reading three paragraphs ago).

Now as to my tank, it’s doing just fine. Fish and plants are healthy. I know I should just let it go, but I’ve gone this far and am hoping to figure this out??

Anyone any thoughts? Should I just forget it? Have I tortured myself enough already? Am I complete nerd now?
 

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They are all going to be very similar, maybe off by a percent at most but certainly not a ton. I would question if you really have kno3.
 

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Discussion Starter · #3 ·
They are all going to be very similar, maybe off by a percent at most but certainly not a ton. I would question if you really have kno3.
Yes, you might be right. Something doesn't add up.

Interestingly I ran across an aquarium ferts site that lists their Kno3 as 13.5-0-46.2.

I looked that up and it is listed as Greenhouse Grade, 13.5% total Nitrogen, 46.2 water soluble potassium.

Is that what they all should be?
 

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All the fertilizers that people sell are going to be ag or greenhouse grade. I dont know what percent purity that will be but it should be perfectly fine.
 

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Discussion Starter · #5 ·
All the fertilizers that people sell are going to be ag or greenhouse grade. I dont know what percent purity that will be but it should be perfectly fine.
OK I ordered some kno3 from another vendor. I've gone this far so am going to try it again. Either I'm a huge idiot or something is not right with my current kno3 (or maybe both!).
 

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Definitely reach out to Orlando @ GLA. He'll make it right if they did ship something else. Maybe it was K2SO4 mislabeled.
 

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Discussion Starter · #7 ·
Definitely reach out to Orlando @ GLA. He'll make it right if they did ship something else. Maybe it was K2SO4 mislabeled.
Bsantucci you are a genius my friend!!

When I read your post, I realized I had another completely unopened kno3 from GLA. I just opened it and made a quick 80ppm and 20ppm solution (getting good at it!). The good news is this batch is fine and my kit seems to be pretty spot on.

The bad news is I have been overdosing something. It's all making sense now. I just bought a phosphate test kit that arrived a few days ago. I couldn't figure out why my phosphates were absolutely through the roof! Pretty sure my kno3 is KH2PO4.
 

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Good to hear you figured it out. I really need to read thru Hoppy's thread that you posted, but it seems from your picture that the API kit is reasonable close. I have been working on bringing my nitrate level back down to a realistic level (was getting between 80 and 160ppm). Now I feel that it is in the 40ish range so I feel better about that. Odd considering I have only been dosing PPS-Pro AND doing 50% water changes on Sunday without dosing on Sunday. Anyway, interesting post for sure.
 

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Discussion Starter · #9 ·
Good to hear you figured it out. I really need to read thru Hoppy's thread that you posted, but it seems from your picture that the API kit is reasonable close. I have been working on bringing my nitrate level back down to a realistic level (was getting between 80 and 160ppm). Now I feel that it is in the 40ish range so I feel better about that. Odd considering I have only been dosing PPS-Pro AND doing 50% water changes on Sunday without dosing on Sunday. Anyway, interesting post for sure.
How old is your API test kit? My old one (maybe 4 years) still reads 80+ on the 20ppm sample. New one looks pretty spot on. They are wildly different.

And one more update. I just tested the kno3 with a Phosphate test kit.......and you guessed it.....the reading was through the roof!

Orlando's a good guy at GLA and I will send him a link to this thread. He's been good to me, and accidents happen.

And I guess phosphates don't necessarily cause algae, because mine has been super high for months! And for a heavily stocked tank with EI dosing, I was surprised that my nitrates were so low. Now I know why...I wasn't dosing any kno3 at all! I wonder if my
K2SO4 is correct?

Oh well, plants and fish doing well....and more importantly don't feel like I am losing my mind now.
 

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How old is your API test kit? My old one (maybe 4 years) still reads 80+ on the 20ppm sample. New one looks pretty spot on. They are wildly different.

And one more update. I just tested the kno3 with a Phosphate test kit.......and you guessed it.....the reading was through the roof!

Orlando's a good guy at GLA and I will send him a link to this thread. He's been good to me, and accidents happen.

And I guess phosphates don't necessarily cause algae, because mine has been super high for months! And for a heavily stocked tank with EI dosing, I was surprised that my nitrates were so low. Now I know why...I wasn't dosing any kno3 at all! I wonder if my
K2SO4 is correct?

Oh well, plants and fish doing well....and more importantly don't feel like I am losing my mind now.
I have a kit that is about 1 year old and I was getting weird results so I bought a new kit. Readings were better, but not much so I realized I need to do more water changes.
I'm sure the GLA guys will take care of you. And as always, Diana has some good advice.
 

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A few months ago, I started to see the classic pinhole potassium deficiency in some of my plants, so I augmented my fertilizing dosing alternating each day with potassium nitrate, potassium sulfate and potassium phosphate. Within a month, no new leaves were showing a potassium deficiency but I saw some stunting in my A. gracilis. I checked my phosphate levels and it was greater than 20 ppm. Subsequently, I eliminated the potassium phosphate supplementation (there is already phosphate in my base solution) and now my A. gracilis leaves look normal again. Within three water changes (25 gallons in a 135-gallon tank every four days), my phosphate level fell from 20+ ppm to 10 ppm. I then changed my fish feeding from twice a day (my angels are always hungry) to once a day. After another three changes, my phosphate level is now 2 to 3 ppm. Hopefully, it will not fall any more because then I will develop phosphate deficiencies.

Mike

Bump:
You can test this with the phosphate and nitrate tests. Ought to test zero for both. At least then you would know it is not KNO3 or KH2PO4.
Diana, I thought it would be beneficial to have a phosphate level between 2 and 3 ppm. Do you maintain your levels at 0 ppm?

Mike
 

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im using gardening grade kno3 and it still delivers expected no3 levels. the purity of virtualy any kno3 available in stores will be more than 99%
 

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Discussion Starter · #14 ·
You can test this with the phosphate and nitrate tests. Ought to test zero for both. At least then you would know it is not KNO3 or KH2PO4.
Diana good point. This weekend I will get it all sorted out. Better order new kits too because I have done so many tests while trying to figure this out.

By the way, I did get a Nitrate reading from the KH2PO4 test with super duper high concentration. However, that is easily explained as I was refilling the original jar of kno3 from the mislabled 1lb bag. I'm sure there was some residual kno3 that came through when I made a really strong batch.
 

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Diana, I thought it would be beneficial to have a phosphate level between 2 and 3 ppm. Do you maintain your levels at 0 ppm?
I am not referring to the level in the tank.

I am suggesting mixing the unknown white powder in the same manner as suggested to make reference solutions for the NO3 test and the phosphorus test.

If you make a reference solution to check the NO3 test, but use something that has no NO3, this test will show zeros no matter what concentration you make.
If you make a reference solution to check the PO4 test, but use something that has no PO4, this test will show zeros no matter what concentration you make.

Thus, if the unknown powder is K2SO4, and you follow the instructions as if it is KNO3 and KH2PO4, you will at least see that the unknown is not KNO3 or KH2PO4.
You still don't really know what it is, but chances are pretty good that if it came with an order of fertilizers it is one of these 3.

Another possibility is that the unknown could be Epsom salt. This is commonly sold as a GH booster. It could be some other GH booster with Ca and Mg. It could be something like Calcium chloride or calcium sulfate.
You can make reference solutions for these, too. (Ca and GH, anyway) Then use a GH test and a Ca test to see whether the GH or the Ca changes or not. If either or both change, then use a formula to calculate the Mg:
((GH in ppm)-(2.5 x Ca in ppm))/4.1 = Mg
a) Neither change = material is not Ca or Mg
b) Ca and GH change, but the mathematical formula shows there is no Mg. = You have some kind of calcium supplement.
c) Ca and GH change, and the mathematical formula shows there is some Mg. = You have some kind of GH booster.
d) Ca does not change, but GH does. = Highly likely Epsom salt, which has Mg, so the GH changes, but no calcium.

Test the KH, too. If GH and KH change, then you may have some calcium carbonate.
If only KH changes, you may have sodium bicarbonate or potassium bicarbonate.

(Gee, planted tank folk can have a lot of fun with white powders...)
 
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