Nitrate Test Assessment

[Uberhoust]

I really only test Nitrates now, all the other normally tested parameters in the tanks haven't changed for months. I currently use an API test but honestly for Nitrate I find it difficult to match the colors and never felt the comfortable with the readings (to me the 10ppm and 20ppm color looks the same). I recently had a tank which I thought had high nitrates and thought I would confirm that with a different Nitrate test. One test showed 5 ppm the other 40? ppm, these readings are at the extreme ends of the values I would expect (I think there is a Chinese proverb about one answer and you know what to do, two answers and you don't have an answer).

I decided to test the Nitrate tests using stump rot (cheap potassium nitrate), distilled water, and a scale, to make my own reference solutions. My methodology is as follows (feel free to check my math)(Note: there are a number of web sites discussing how to make a reference solution, but I believe some haven't done the math right):

1. Took the molecular weight of KNO3 101.102 and NO3 62.004
2. Determined the mass of KNO3 required for 1 gram of NO3 101.102 / 62.004 = 1.631 grams for 1 gram NO3
3. Baked the KNO3 in the oven at 125 C for 2 hours perhaps should have been longer but the powder was spread thin into a couple of crucibles.
4. Added approximately 6.5 grams of KNO3 to 500 ml of distilled water to create a 8000 ppm solution of NO3 (this is the least accurate phase other than the nitrate source)
5. Converted the 8000 ppm solution to a 100 ppm solution by adding 2.5 grams (using a syringe and scale) to 197.5 ml of distilled water.
6. Did the second test with the 100 ppm water. The first was with the aquarium water.
7. Later tested other concentrations including 5, 10, 20, and 40 ppm solutions using the 100ppm solution mixing 5, 10, 20, and 40ml with distilled water to make 100 ml of reference solution.

What I found is that the Fluvial Nitrate test did not ever register beyond 5ppm but the the result of the assessment is I now have a reference photos for the API test, taken under my lighting conditions. Below are the results:

The Lab , the tank on the left is the corner of my betta tank that has been going for about a month. It still needs some work, I use my left over Vals to slow down the current.

The 100 ppm test, the Fluval test is clearly not working or is adversely affected by the K in the water. I prefer the intensity gradation vs. color change, but only if the test works. Note the dark red color of the API test indicating somewhere between 80 and 160. I will never let my tanks get to that level so didn't spend much time with those results.

The results of the 5, 10, 20, and 40 ppm, I now have reference image using lighting that is very easy to reproduce. The results to my way of thinking is light orange and orange is ok, but when you get a hint of red the Nitrates are getting too high. One observation is that when I looked at the test tubes as I normally do the colors seem pretty similar but when I photographed them the colors stood out and it was easier to assess the results.

I have contacted Fluval about their test and got an immediate response. They are sending me a new test kit and asked how I perform the tests, they mentioned that my Nitrate test kit was defective. I have since come across that both test kits have a reagent the leaves solution rather easily which is why you have to shake them vigorously. I have typically had good results from both Fluval and API products, and I am only presenting this for interest sake.

I would like to test ammonia, and nitrite just for fun, but both are more difficult than Nitrate for various reasons.

 

[PheonixKingZ]

Very professional looking!

 

[AbbeysDad]

That's all quite great and a huge effort. After years of squinting into the API test tubes, I adopted a very simple approach for nitrate test results...
yellow = great, orange = okay, red = bad
But quite honestly, with routine 50% water changes in established tanks, I rarely find a need to do any testing at all.

Footnote: Btw, you have to really shake and tap on a solid surface regent #2 of the API nitrate test as there is a component that separates. Failure to do so may compromise not only one, but all future tests with that regent.

 

[Uberhoust]

I have really come to the same solution regarding the test kits. I enjoy experimenting, the only thing I avoid is where an experiment will cause harm to the fish. I haven't been doing 50% weekly changes but lately I have been approaching that level lately.

 

[Fishmanic]

I use Salifert’s freshwater nitrate test kit. It is much simpler to perform and is much easier tor read results.

 

[Arthur11]

I use Qguai aquarium test strips. I only need a couple of minutes to finish testing. The only thing I should do is dip the test strip into the water for no more than two seconds.

 

[Essjay]

I thought you used Runbo test strips

If you do not have enough room in your budget for a steady supply of highly accurate liquid testing kits, then I think this RUNBO aquarium test stripsis the best thing. These test strips are surprisingly accurate for their type of kit. I have heard some people complain that the test strips are not very dependable because they are not consistent. This means that two strips may provide vastly different results. So far, I have not experienced any inconsistencies using this test kit, and I am almost halfway through the 100 test strips.

 

[itiwhetu]

I use API test strips any color on Nitrite or Nitrate not good. So I only am looking for a clear result when testing.

 

[Arthur11]

I thought you used Runbo test strips

It was last year when the covid epidemic was not yet developing rapidly in our area. After using up all of Runbo's test strips and I can't find them at the stores near my house. A friend of mine gave me this test kit, it feels pretty good. Will come back to Runbo soon when the epidemic has stabilized

 

[AbbeysDad]

After learning that I had high nitrates in my well water years ago, I obsessed over nitrates. It's like once you see something, you just can't unsee it! In time, relying more on good tank maintenance, especially sufficient volume/frequency of partial water changes to keep tank generated nitrates in check, I've relaxed and today I test very infrequently.
I'm not suggesting that we don't do any testing or that we should ignore high nitrates. But by the same token, we shouldn't bother testing every time we turn around and fret over result values - life's too short and will go on.

 

[Uberhoust]

@AbbeysDad I am seeing your point. I test once and a while now but I no longer maintain a weekly log of my test results. I believe this is partially because since joining this group I do much larger water changes, it really doesn't take too much longer to do a 50% change vs a 20% change. With the larger weekly changes there is much less time for issues to arise.

 

[StevenF]

My methodology is as follows (feel free to check my math)(Note: there are a number of web sites discussing how to make a reference solution, but I believe some haven't done the math right):

1. Took the molecular weight of KNO3 101.102 and NO3 62.004
2. Determined the mass of KNO3 required for 1 gram of NO3 101.102 / 62.004 = 1.631 grams for 1 gram NO3
3. Baked the KNO3 in the oven at 125 C for 2 hours perhaps should have been longer but the powder was spread thin into a couple of crucibles.
4. Added approximately 6.5 grams of KNO3 to 500 ml of distilled water to create a 8000 ppm solution of NO3 (this is the least accurate phase other than the nitrate source)

Your math looks correct however you could have avoided the math by using a fertilizer nutrient calculator. Such as rotalabutterfly.I used it to make my own fertilizer.