Big nitrate testing discrepancy. Which to trust?

[moz71]

Funny thing is that I am not saying I don’t trust Salfiert what I am saying is I don’t trust my eyes. We all see things differently. This test could be the most accurate but like lust like @Lyss I like the results of Hanna better! And I will just confirm with periodic icp test

 

[JayA]

API and Salifert are subjective tests. That means it depends upon the user and mostly their ability to see and match colors accurately. The main thing is consistency and real life. Choose a test you like and don't chase the number, chase the look in/of your tank.

 

[Lyss]

API and Salifert are subjective tests. That means it depends upon the user and mostly their ability to see and match colors accurately. The main thing is consistency and real life. Choose a test you like and don't chase the number, chase the look in/of your tank.

Oh, I’m def not chasing a specific number — just want to be sure my nitrates aren’t constantly at 50! If that’s the actual case I’ll need to find the source and address it. Hopefully checking the Hanna calibration will resolve for me whether or not I can trust it…

 

[Shirak]

I like the NYOS, there seem to be a nice range with clear color differences between them so even if you can't say exactly this one or that you can tell if it's close. I just picked up the Hanna HR so will see how that compares later when I have a chance to run both.

 

[taricha]

I'd lean toward the Hanna NO3.
Eyeballs and a color card are always going to mean two people can look at the same test and decide its off by a factor of ~2x.
The other chem kits are likely great. And if you could run those through a digital eyeball to monitor them - they'd probably give you very good info.

 

[Rmckoy]

I would personally trust salifert .
I found the Hanna nitrate test kit to be a pain in the butt .
Depending on where you are in terms of what’s stocked in your tank . Nitrates a little higher is ok .
Yo yo definitely don’t want to lower them too far .
For the first few years . I used api . It might have been inaccurate but it was a guideline to say it was most likely high

 

[Shirak]

I would personally trust salifert .
I found the Hanna nitrate test kit to be a pain in the butt .
Depending on where you are in terms of what’s stocked in your tank . Nitrates a little higher is ok .
Yo yo definitely don’t want to lower them too far .
For the first few years . I used api . It might have been inaccurate but it was a guideline to say it was most likely high

Which Hanna? I just used the HR Hanna HI782 and it was quite easy. Took a few minutes longer than the NYOS but it's in the same time frame as many other nitrate kits I have used in the past.

I tested nitrate on both my tanks with the NYOS and the new HR Hanna. One tank was reading around 1ish ppm NYOS and came up .2ppm on the Hanna Yes... working on that. It's been low for a bit so I have been feeding the corals heavily directly and broadcast as well each day.

The DT was reading around 4ppm NYOS and the Hanna came up with 2.9ppm
I am quite happy with the HR Hanna. Just have to get more reagent. Price range is around the same cost per test as the NYOS.

 

[PatW]

It really depends. It depends on what you are trying to do. If you have a fish only system and are not having algae problems, I would say you are fine. Heck if you are growing softies or LPS and don’t have algae issues and your corals are happy, you are probably fine.

Basically, only SPS corals have issues with nitrates above 10% or 20% and some people not even then.

I use the Red Sea Pro Nitrate test but Salifert is pretty similar. I have not fooled with the Hanna. The Hanna sounds compelling but in my experience their ALK test has the same level or variation as Red Sea Pro and Salifert.

Now I run a low nutrient SPS dominant trending to acropora. So I run my nitrates pretty low and I have no issues as long as I have some nitrates.

Randy Holmes Farley probably has posted a way of making a nitrate standard. It would just entail adding X grams of Sodium nitrate to Y grams of RODI. But you would need the figures and an accurate scale.

 

[Harold999]

Look up what the nitrates are in your tap water (check the website of your water supplier or call/email them), and test it, and see which one of your testkits is right.

I think you will have to add salt first because saltwater and freshwater nitrate testkits are not the same but not sure about this.

Edit: adding salt is not necessary with the Salifert kit and many others, it works with fresh and saltwater. Hannah not sure.

 

[Randy Holmes-Farley Verified Community Expert]

Look up what the nitrates are in your tap water (check the website of your water supplier or call/email them), and test it, and see which one of your testkits is right.

I think you will have to add salt first because saltwater and freshwater nitrate testkits are not the same but not sure about this.

Edit: adding salt is not necessary with the Salifert kit and many others, it works with fresh and saltwater. Hannah not sure.

I suppose some might be quite stable, but my water company says the range is from 0.04 ppm to 0.145 ppm.

 

[Harold999]

I suppose some might be quite stable, but my water company says the range is from 0.04 ppm to 0.145 ppm.

With such low values it will be hard to get accurate numbers from a testkit anyway unless you have the Hannah low ranger.
Are such low values common in the US? Here in the Netherlands it's more like 7 ppm where i live, and in this case i can easily see if a testkit is way off or not.

 

[Lyss]

With such low values it will be hard to get accurate numbers from a testkit anyway unless you have the Hannah low ranger.
Are such low values common in the US? Here in the Netherlands it's more like 7 ppm where i live, and in this case i can easily see if a testkit is way off or not.

I’m in NYC — just checked and ours is reported as 0.158. Says the legal limit is 10.

I run a freshwater tank, too, that I now use RO/DI for and remineralize b/c I had unstable Ph w/tap — but when I was using tap I would periodically test, and nitrates were always undetectable w/a basic API kit.

 

[Harold999]

I’m in NYC — just checked and ours is reported as 0.158. Says the legal limit is 10.

I run a freshwater tank, too, that I now use RO/DI for and remineralize b/c I had unstable Ph w/tap — but when I was using tap I would periodically test, and nitrates were always undetectable w/a basic API kit.

Yeah with such low numbers (<1) you can forget my idea.
Altough you could look which testkit is the closest to that. With Salifert you can also look from the side instead of the top and you should divide the value into 10 then.
Reading .2 ppm or even lower is possible then.

 

[Malcontent]

Plenty of places sell nitrate standards:

Hach Nitrogen-Nitrate Standard Solution

Nitrogen-Nitrate standard solution

www.fondriest.com

Those are in nitrate-N so you have to multiply by 4.43.

 

[Lyss]

Well, I just received the calibration standard from Hanna, checked, and my HR Nitrate checker is good -- the certificate it comes with says it must be between 31.2 and 38.8 ppm. I plan to use and trust this checker going forward, but will probably do an ICP test at some point anyway as a double-check.

 

[Randy Holmes-Farley Verified Community Expert]

Well, I just received the calibration standard from Hanna, checked, and my HR Nitrate checker is good -- the certificate it comes with says it must be between 31.2 and 38.8 ppm. I plan to use and trust this checker going forward, but will probably do an ICP test at some point anyway as a double-check.

Just understand, you didn't actually check whether the checker is giving correct values, only that the electronics are working as expected. The chemical reagents, the hands on method, or even scratches on the cuvettes may still lead to wrong values.

They should not be calling this a calibration standard. That would be seawater with phosphate in it that you tested. It more of a machine check.

 

[Lyss]

Just understand, you didn't actually check whether the checker is giving correct values, only that the electronics are working as expected. The chemical reagents, the hands on method, or even scratches on the cuvettes may still lead to wrong values.

They should not be calling this a calibration standard. That would be seawater with phosphate in it that you tested. It more of a machine check.

That's what I wanted to accomplish though, right? To make sure the machine was working properly. The numbers I consistently get when using this as compared to the numbers I consistently get when using other test are very different, so I was feeling more wary of this particular device and didn't want to blindly trust that it was working properly.

You do get two cuvettes -- one that is clear to zero out the machine, and one that is pink like when you add the reagent. Is this not meant to make sure the device is calibrated? I realize that if it wasn't there wouldn't be anything I could do about it other than contact Hanna.

 

[mdb_talon]

You do get two cuvettes -- one that is clear to zero out the machine, and one that is pink like when you add the reagent. Is this not meant to make sure the device is calibrated? I realize that if it wasn't there wouldn't be anything I could do about it other than contact Hanna.

I see some value to confirm it is working i guess, but seems like a much better test would be an actual solution with a known level of nitrates. My issues with hanna accuracy have been with different regeant batches giving significantly different results(way outside the margin of error).

 

[Lyss]

I see some value to confirm it is working i guess, but seems like a much better test would be an actual solution with a known level of nitrates. My issues with hanna accuracy have been with different regeant batches giving significantly different results(way outside the margin of error).

I see. So far, I've used the batch the device came with, and then a new batch I'd ordered when they first became available, and have seen pretty consistent results with each use, as well as a progression of nitrates beginning to drop w/progression of carbon dosing over the past couple of months.

To this day when I use API I get that my nitrates are somewhere between 40 and 80, which is like, what. I see the Salifert test as a middle ground between the two and have pretty consistently gotten readings of 25 or somewhere less than but close to that unless I truly think my nitrates may have spiked -- like on one occasion when I overfed reef roids and phyto.

 

[Randy Holmes-Farley Verified Community Expert]

That's what I wanted to accomplish though, right? To make sure the machine was working properly. The numbers I consistently get when using this as compared to the numbers I consistently get when using other test are very different, so I was feeling more wary of this particular device and didn't want to blindly trust that it was working properly.

You do get two cuvettes -- one that is clear to zero out the machine, and one that is pink like when you add the reagent. Is this not meant to make sure the device is calibrated? I realize that if it wasn't there wouldn't be anything I could do about it other than contact Hanna.

I'd rather confirm the test was working correctly. It's like checking to see if a car motor is working, but not checking if the driver knows how to drive. lol

The test with the color standards in no way validate the overall method or the reagents or procedures used.