ICP test vs Hanna Checkers

[Science/G]

Sorry to disagree, but it shows that your tester is performing accurately if the test using the standard falls within the standard deviation of +/- 70 of 1400. So if the kit is accurate and as an experienced reefer and science teacher, my methods and measurements are also, my test is accurate within the standard deviation.

 

[Pod_01]

Sorry to disagree, but it shows that your tester is performing accurately if the test using the standard falls within the standard deviation of +/- 70 of 1400. So if the kit is accurate and as an experienced reefer and science teacher, my methods and measurements are also, my test is accurate within the standard deviation.

Just a suggestion. One way to get more confidence with Hanna, is to mix fresh batch of saltwater. Hopefully your salt states what Mg is when mixed at 35PSU. Let it sit for few days (to make sure all the particles are mixed and dissolved, we don’t want another discussion my brand new salt mix is low on Mg). Now use Hanna to get Mg value. Repeat it 3 times or 16 to capture the variation If any.
If you decide that Hanna is correct and the actual Mg is elevated stop adding Mg and water changes will bring it down over time.
But I will be frank, the money I spend on figuring out Mg, I could have gotten nice $$$ corals. These days I ignore it mostly and water changes keep it optional (based on monthly ICP tests). I been told there are corrals that can tell you when your Mg level drops to a low level so there is that option.

 

[Science/G]

I use natural seawater so a test should be pretty straightforward

 

[Rick Mathew]

I use natural seawater so a test should be pretty straightforward

I am beginning to believe there is not to many things that are "straight forward" in seawater testing :astonished-face::)

 

[Rick Mathew]

Just a suggestion. One way to get more confidence with Hanna, is to mix fresh batch of saltwater. Hopefully your salt states what Mg is when mixed at 35PSU. Let it sit for few days (to make sure all the particles are mixed and dissolved, we don’t want another discussion my brand new salt mix is low on Mg). Now use Hanna to get Mg value. Repeat it 3 times or 16 to capture the variation If any.
If you decide that Hanna is correct and the actual Mg is elevated stop adding Mg and water changes will bring it down over time.
But I will be frank, the money I spend on figuring out Mg, I could have gotten nice $$$ corals. These days I ignore it mostly and water changes keep it optional (based on monthly ICP tests). I been told there are corrals that can tell you when your Mg level drops to a low level so there is that option.

This would be a good approach to give a good picture of the precision (Repeatability) of your test method but the accuracy results would be directly related to the accuracy of the reported value of the magnesium level from the salt supplier as well as the ability to mix the salt to 35PPT.

 

[Pod_01]

This would be a good approach to give a good picture of the precision (Repeatability) of your test method but the accuracy results would be directly related to the accuracy of the reported value of the magnesium level from the salt supplier as well as the ability to mix the salt to 35PPT.

You are correct on all counts, measuring Mg is like going down a rabbit hole so I gave up some years back. The measurement is sensitive to salinity and you are correct the assumption is the salt batch is good etc…
But at least one will know if Hanna is providing repeatable results or not. Also if the measured value for fresh water falls within 1200-1450 I would call it a day. Good enough for the tools used.
One can always experiment further, it is hobby after all.

 

[Randy Holmes-Farley Verified Community Expert]

Sorry to disagree, but it shows that your tester is performing accurately if the test using the standard falls within the standard deviation of +/- 70 of 1400. So if the kit is accurate and as an experienced reefer and science teacher, my methods and measurements are also, my test is accurate within the standard deviation.

It shows the tester electronics are working correctly. It says nothing about accuracy of the test which requires the reagents and procedures and cuvette used to function as Hanna hopes they will.

I don’t think it is an especially useful test. A real calibration standard would be far more useful.

 

[Randy Holmes-Farley Verified Community Expert]

I just ran an ICP analysis test. Most of the numbers came back within an acceptable range. I was most interested in my trace elements numbers. I use natural seawater for water changes and have been successfully adding trace elements and iodide for the last 6 months to boost levels a bit. I have seen improvements in color and growth. My "indicator coral" is a super red montipora digitata that looks amazing after I dose......Back to the ICP test. My magnesium on the test measured 1269. My Hanna checker 1525. I just used the certified standard calibration kit from Hanna and my checker was slightly on the high side, but well within the standard deviation of +/- 70. I believe my Hanna and not the ICP. Thoughts?

You do not mention whether you have been dosing magnesium or what you believe the salinity is. Magnesium can only get above 1300 ppm in natural seawater if you have dosed it up, or the salinity is higher than 35 ppt.

 

[Syntax1235]

I’ve had similar troubles with Hanna and Icp, in my case phosphate. I Reeflabs Icp came back with .003 phosphate and Hannah read.14. I assumed the Hanna was incorrect so I decided to buy the reference standard cuvettes. The reading from the Hanna was within .01 of the cuvette reference. I have no idea which test is correct at this point. It is frustrating.

 

[gbroadbridge]

I’ve had similar troubles with Hanna and Icp, in my case phosphate. I Reeflabs Icp came back with .003 phosphate and Hannah read.14. I assumed the Hanna was incorrect so I decided to buy the reference standard cuvettes. The reading from the Hanna was within .01 of the cuvette reference. I have no idea which test is correct at this point. It is frustrating.

I tend to trust the Hanna as it is testing a water sample within minutes of being collected, whereas the ICP happens days later when it is possible biological or chemical processes in the sample may have reduced the Phosphorus level.

I have never had an ICP read higher than the Hanna checker.

 

[Randy Holmes-Farley Verified Community Expert]

I’ve had similar troubles with Hanna and Icp, in my case phosphate. I Reeflabs Icp came back with .003 phosphate and Hannah read.14. I assumed the Hanna was incorrect so I decided to buy the reference standard cuvettes. The reading from the Hanna was within .01 of the cuvette reference. I have no idea which test is correct at this point. It is frustrating.

While magnesium cannot change in a sample waiting for analysis, phosphate can. Thus, comparing a delayed test to an immediate test may not give the same results even if both methods are perfectly accurate.

 

[KStatefan]

I only have one observation so far but my last ICP was sent in May sample water taken at the same time my magnesium results.
Hanna 1330 ppm
Reef-Labs 1338 ppm
Oceamo 1288 ppm

 

[Rick Mathew]

I’ve had similar troubles with Hanna and Icp, in my case phosphate. I Reeflabs Icp came back with .003 phosphate and Hannah read.14. I assumed the Hanna was incorrect so I decided to buy the reference standard cuvettes. The reading from the Hanna was within .01 of the cuvette reference. I have no idea which test is correct at this point. It is frustrating.

I would trust the Hanna results!...Here is why...

https://www.reef2reef.com/ams/sample-storage-and-its-impact-on-measurement-results-part-3.800/

 

[Reefahholic]

I have a couple results you guys might find interesting. These results were all taken the same day (around the same time) I sent water to the lab. You can see my results vs the ICP results. I find that both ATI and OCEAMO are pretty close with Alkalinity, Phosphate, and Nitrate.

 

[Reefahholic]

and out of those two I use Fauna Marin ICP. They have real live coral farm as a proof that they know how to properly use the technology and they know how to care for corrals.

They also have Green Spectro ICP machines in house, and are able to test multiple times a day which gives them the advantage of other companies using the same OES machines. Plus, Claude provides feedback to dial in their results.

 

[Supa]

I just ran an ICP analysis test. Most of the numbers came back within an acceptable range. I was most interested in my trace elements numbers. I use natural seawater for water changes and have been successfully adding trace elements and iodide for the last 6 months to boost levels a bit. I have seen improvements in color and growth. My "indicator coral" is a super red montipora digitata that looks amazing after I dose......Back to the ICP test. My magnesium on the test measured 1269. My Hanna checker 1525. I just used the certified standard calibration kit from Hanna and my checker was slightly on the high side, but well within the standard deviation of +/- 70. I believe my Hanna and not the ICP. Thoughts?

I see some slight differences in mine often too. I typically go by the hanna checker numbers. Unless the ICP test number looks better then I become lazy reefer and go with that number

 

[Pod_01]

have a couple results you guys might find interesting.

Here are mine just to confuse everyone:
Hanna:

ICP results:

So Alk off by 1dKh, but my most recent Hanna regent bottle has been running 1dKh higher compared to the previous bottle.

PO4 as in the Ortho is close ICP lab 0.02, Hanna 0.05 and I had some across perish at that time so I do believe the ICP results. I knew I was in trouble.

NO3 exactly the same, I find that really amusing. Hanna claims the accuracy is:

So not sure what to make of the NO3 results.

Anyways to resolve my Alk dilemma I also got the GHL KH Director. So now I have Hanna, FM titration Alk test and KH director and tonight I ended up with 3 different results. Soooo I will average them lol.

I hate testing…..

 

[Reefahholic]

One thing I want to point out about Plasma Interfaces.

Fauna is using a dual side radial view for their seawater testing. OCEAMO is using a axial plasma view.

Let’s look at some differences:

An Axial-view system looks from end to end of the plasma’s entire axis. It observes everything going on in the excitation channel.

The Radial-view system looks across the plasma. It sees only a narrow cross section of light rather than the light from the whole length.

Having less light to process, a Radial system can’t match the “sensitivity” of a Axial system in detecting trace elements.

Radial can be more precise and require less maintenance, but you loose sensitivity.

Axial-view detection limits surpass Radial-view performance by a factor of 10. Performance of the new Radial machines have improved, but most labs aren’t running them. They still have the older machines. However, for those that maybe updated their machines, Axial detection limits are still “2-3x lower” than Radial and get you the “lowest detection limits” possible using a ICP-OES machine.

They do require more cleaning and are less stable, but if the operator keeps the machine clean it’s not a problem.

I believe this is why Fauna has
Switched to the Spectro green for seawater sampling. They have a lot of testing going on, and want to avoid having to clean the machines frequently, but they’ve sacrificed sensitivity. It’s great for them, but not so great for us.

 

[Randy Holmes-Farley Verified Community Expert]

I have a couple results you guys might find interesting. These results were all taken the same day (around the same time) I sent water to the lab. You can see my results vs the ICP results. I find that both ATI and OCEAMO are pretty close with Alkalinity, Phosphate, and Nitrate.

Of course, those are not actually icp results for alk or nitrate, and doesn’t say much about icp.

 

[Pod_01]

Of course, those are not actually icp results for alk or nitrate, and doesn’t say much about icp.

Some of these should be called ICP+…..
But fun regardless to see what they get vs. at home test reslilts.