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never buying another api test again

1382 Views 7 Replies 2 Participants Last post by  Seattle_Aquarist
so recently i discovered that my api nitrate test kit was defective .. funny because it was dead accurate for the first 2 weeka of using it , anyway i went and shelled out 12 bucka for another one today and guess what? same exact results as the previous kit . now currently my plants are showing signs of nitrate deficiancy and these crap test kits are making it a hard problem to fix since i dont wanna start throwing kno3 at my tank nd just hoping that that is the issue .. anyway does anyone have any thoughts about the seachem nitrate nitrite test kit ? or is there somethimg better in that price range?

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Hi Sucram Nosiren,

How do you know that your nitrate test kit is inaccurate; did you check it against a solution with a known NO3- ppm level?
i had the water company take some of my water to test on the machine they have , they called me back and said it was 5 ppm , which is what my first nitrate kit read before it went wacky

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Hi Sucram Nosiren,

I'm sure your realize that our water can change due to weather, season, and water source changes. The water that was 5ppm in summer could be substantially lower in the winter for instance.

If your test result is "0" (zero) it is possible that is your current NO3- ppm level. Or it could be what happened to me several years ago with an API Nitrate test kit......see post #15 in this thread.

Now I have calibration solutions of 100 ppm KNO3 that I mixed up using a calibrated gram scale and a lab beaker. I dilute the 100ppm solution with distilled water to make 10ppm, 20ppm, and 40ppm test solutions for my test kits.
Hi Sucram Nosiren,

I'm sure your realize that our water can change due to weather, season, and water source changes. The water that was 5ppm in summer could be substantially lower in the winter for instance.

If your test result is "0" (zero) it is possible that is your current NO3- ppm level. Or it could be what happened to me several years ago with an API Nitrate test kit......see post #15 in this thread.

Now I have calibration solutions of 100 ppm KNO3 that I mixed up using a calibrated gram scale and a lab beaker. I dilute the 100ppm solution with distilled water to make 10ppm, 20ppm, and 40ppm test solutions for my test kits.
it was literally last wednesday that they came and tested my water and even told me which well was supplying my water and that they would have to shut everything down if nitrates went over 10 ppm .. i did follow directions ... even though they are a pain in the ash i shake bottle number 2 for well over 30 seconds even smacking the bottom on the table and i make sure solution number 1 is completely mixed with the water before adding number 2 and i shake it like crazy and its reading 40 to 80 straight from the tap

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Hi Hi Sucram Nosiren,

Is it possible the water company is adding something to the water that is throwing off the test? One option to test the accuracy yourself is to make your own solution with a known NO3- ppm and see what the test kit reads.
Hi Hi Sucram Nosiren,

Is it possible the water company is adding something to the water that is throwing off the test? One option to test the accuracy yourself is to make your own solution with a known NO3- ppm and see what the test kit reads.
could i use kno3?

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Hi Sucram Nosiren,

Quoting from Rex Grigg (now archived at on rotalabutterfly.com) here are his comments on various test kits and how to make a nitrate calibration solution.

Test Kits

For a planted tank there are a few test kits that you really should have on hand. These are pH, kH, gH, nitrate, and phosphate. Don't waste your money on iron test kits as they are very unreliable and not worth the money. Same goes for potassium test kits. So you might ask how does one know how much potassium to add. See the section on Fertilizers for that answer.

As far as what test kits work best. Well Lamotte are the best, but they run around $70 each. What I use is the Wardley's mid-range pH test kit, the Aquarium Pharmaceuticals gH and kH, and the Red Sea nitrate and phosphate test kits. One of my Bit's Of Wisdom is “Never test your test kit in your tank”. Now I'm going to tell you how to test your Nitrate test kit.
Testing Your Nitrate Test Kit

Take 1000ml of water. Dissolve 6.5 grams of KNO3 in it.
Take 1 gallon of water. Each ml of the above solution will add 1 ppm of NO3.
Add 5 ml, test. Your test kit should show 5 ppm.
Add 5 more ml, test. Your test kit should show 10 ppm
Repeat through the range of your test kit.
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