Big nitrate testing discrepancy. Which to trust?

[Lyss]

Hi! I’m wondering what others think about this…

I’ve been working on lowering nitrates for the past few months. Initially I was using the API test, which has been reading strikingly high: never under 30 ppm, often 40 or 50+

So I bought a Salifert kit and that tends to show somewhere in the 25 - 30 range consistently.

I also test w/the new Hanna HR Nitrate checker and that one is consistently telling me my nitrates are between 10 and 20 ppm. Usually somewhere around 12.

So I guess my Q is: What are opinions on which test to trust? I’m carbon dosing to lower nitrates, and back to doing weekly water changes, but I don’t want to be overly aggressive if, say, the Hanna one is most likely correct.

 

[Spare time]

I'd trust the hanna personally if performed perfectly (meaning inserting the vial the same way, using a microfiber cloth on the vial, and rinsing with ro water after). I would just pick one and stick with it. I find the api to be troublesome.

 

[homer1475]

Hard to say really. API doesn't have enough resolution, Salifert is matching colors, and the Hanna is a hard number.

Pick one and use that. Personally I would use, and do use the hanna, just for sake of ease of use, and a hard number(I hate matching colors!).

 

[Reef.]

Hi! I’m wondering what others think about this…

I’ve been working on lowering nitrates for the past few months. Initially I was using the API test, which has been reading strikingly high: never under 30 ppm, often 40 or 50+

So I bought a Salifert kit and that tends to show somewhere in the 25 - 30 range consistently.

I also test w/the new Hanna HR Nitrate checker and that one is consistently telling me my nitrates are between 10 and 20 ppm. Usually somewhere around 12.

So I guess my Q is: What are opinions on which test to trust? I’m carbon dosing to lower nitrates, and back to doing weekly water changes, but I don’t want to be overly aggressive if, say, the Hanna one is most likely correct.

I would trust the Hanna, but your nitrates are not that bad, no drastic measures needed.

Not sure what measures you have been using but one simple water change of 50% would have brought nitrates down to 10 if they were at 20 and even at 20 that is not high.

 

[Lyss]

I would trust the Hanna, but your nitrates are not that bad, no drastic measures needed.

Not sure what measures you have need using but one simple water change of 50% would have brought nitrates down to 10 if they were at 20 and even at 20 that is not high.

Well, the issue was that before I had the Hanna the other tests were telling me between 30 and 50, sometimes 50+ which is too high.

Then I got the Hanna and it was telling me 20, which with carbon dosing has become 12 - 15. The other two tests still read high.

I ran out of Hanna reagent and just before I posted this did API — that told me 50. Two days ago when I used my last hanna reagent it said 11.3. That’s a big difference between tests, but if the hanna is the most trustworthy then I’m gonna dial back the carbon dosing.

I am back to doing weekly water changes until nitrates are back in 5 - 10 range.

 

[X-37B]

I like and use Nyos. Salifert is backup as its harder to read for me.

 

[Spare time]

Salifert seems to be easy to mess up given how little water is used and how it has very wide ranges between reading points. API is almost useless because I've never met anyone who can say it's x color for sure. It's always a "maybe 10?"


My go to tests are the red sea pro, nyos, and likely the hanna hr if I ever get it. I am colorblind so this is especially difficult for me but these seem to be readable by me, which means that it should definitely be for most people

 

[kittenbritches]

Well, the issue was that before I had the Hanna the other tests were telling me between 30 and 50, sometimes 50+ which is too high.

Then I got the Hanna and it was telling me 20, which with carbon dosing has become 12 - 15. The other two tests still read high.

I ran out of Hanna reagent and just before I posted this did API — that told me 50. Two days ago when I used my last hanna reagent it said 11.3. That’s a big difference between tests, but if the hanna is the most trustworthy then I’m gonna dial back the carbon dosing.

I am back to doing weekly water changes until nitrates are back in 5 - 10 range.

Are you testing with all three kits concurrently, or one at one time, and another later?

 

[arking_mark]

For NO3, I like the Nyos test kit.

 

[Lyss]

Are you testing with all three kits concurrently, or one at one time, and another later?

Both. Usually concurrently but today I couldn’t do Hanna b/c I ran out of reagent finally.

 

[kittenbritches]

Both. Usually concurrently but today I couldn’t do Hanna b/c I ran out of reagent finally.

That's crazy. Everyone hates API so much that when I cycled I tested API and Red Sea concurrently and consistently got nearly identical results. Sooo...I will continue to use API until I run out because it's faster and easier. I haven't checked against anything digital, but my test results always align with what's going on in my tank.

Are you rinsing and drying all vials in the same way? How do you collect your test water? Do you use a timer or stopwatch for the shaking? There has to be some variable that explains why the tests vary so widely! I want to solve the mystery. Haha

 

[mdb_talon]

Out of those three i would personally trust the Salifert far more than the others.

 

[Lyss]

That's crazy. Everyone hates API so much that when I cycled I tested API and Red Sea concurrently and consistently got nearly identical results. Sooo...I will continue to use API until I run out because it's faster and easier. I haven't checked against anything digital, but my test results always align with what's going on in my tank.

Are you rinsing and drying all vials in the same way? How do you collect your test water? Do you use a timer or stopwatch for the shaking? There has to be some variable that explains why the tests vary so widely! I want to solve the mystery. Haha

I have a little 3D printed drying rack for the vials, then I wipe them out w/a paper towel and rinse w/tank water before taking the sample. And I’m super meticulous w/Hanna — wiping the cuvette w/a microfiber cloth and making sure no bubbles before taking the reading. Test water collected w/a clean pipette. Stopwatch on my phone for all.

The weird thing is they are all individually consistent — API always high, Hanna on the lower end, and Salifert typically somewhere in between.

a few ppl have recommended Nyos so I might try that until Hanna has HR nitrate reagents available again.

 

[vtecintegra]

Buy the calibration standard that goes with the checker. Then you will know it's accuracy which you can't do with the others. And saltwateraquarium shows over 500 reagents in stock. I'd trust the hanna if I had to chose.

 

[Lyss]

Buy the calibration standard that goes with the checker. Then you will know it's accuracy which you can't do with the others. And saltwateraquarium shows over 500 reagents in stock. I'd trust the hanna if I had to chose.

Omg, I signed up for the stock notification everywhere but must have missed it. Thanks!

 

[moz71]

I have a little 3D printed drying rack for the vials, then I wipe them out w/a paper towel and rinse w/tank water before taking the sample. And I’m super meticulous w/Hanna — wiping the cuvette w/a microfiber cloth and making sure no bubbles before taking the reading. Test water collected w/a clean pipette. Stopwatch on my phone for all.

The weird thing is they are all individually consistent — API always high, Hanna on the lower end, and Salifert typically somewhere in between.

a few ppl have recommended Nyos so I might try that until Hanna has HR nitrate reagents available again.

I think if you go to another test kit your just gonna get another number to be confused on. I was using seilfert for the longest time which I thought was reading the colors correctly and then did an icp test and was way off. Just so hard to read the shades of color. I switched to Hanna HR checker and have been more than confident. Anyhow but maybe the Nyos will give you something close to the others that give you comfort

 

[FactoryKTMmotocross46]

I wouldn't go off of what anyone trusts personally, there are many variables that could be affecting your test results. Get an ATI icp test done and test the water with all of your kits at the same time. See which one matches the icp closest.

 

[Spieg]

I had the opposite results... Nyos test was only reading around 10-20 but the Hanna HR says 42. I don't have any algae problems so not sure I trust the Hanna at this point.

 

[Lyss]

I had the opposite results... Nyos test was only reading around 10-20 but the Hanna HR says 42. I don't have any algae problems so not sure I trust the Hanna at this point.

I ended up buying more reagents along w/the calibration standard — interested to see what that reveals. Secretly I don’t trust mine either, but I want to b/c I like the numbers better! And everyone has been raving about it so I felt odd questioning it. If I still question it after that, I’ll do an icp test.

 

[vtecintegra]

Post back after checking calibration. I've checked my alk, phos, and copper meters and they've all been good. Even my alk meter that's over 5 years old is still good. I haven't gotten the nitrate standard yet.