Accuracy of Phosphate ICP analysis

Rick Mathew · Aug 13, 2019

cjpitt80 said:
All at one time. Make salt. Let it mix for a full day or so. Check salinity. Recheck. Change. I use a standard 13gal trash can. I have a 75gal with 29gal sump. About 80 gal total water volume, so I figure about 15% WC or so. Did my 2nd one this past weekend

Ok...Just a for what it is worth. I used to do the "mass change" method 10-15%/week (15 to 20 gal /week on my 150) also. I found it created more instability in my system thank I liked so I went to smaller changes over the week...now I am using a Neptune DOS and doing continuous changes (about 2 gal/day---15 gal/week) This improved my take stability and my critters appeared to like this better. The theory being that smaller changes have less of an impact on the tank perimeters (pH, Salinity, Temp and other stuff effected by introducing "new water" I now only do bigger water changes if I am in trouble with (Nitrates, Phosphate or some other issue. My strategy is small changes in everything...Water change, dosing, any treatments for issues ETC.

cjpitt80 · Aug 13, 2019

Rick Mathew said:
Ok...Just a for what it is worth. I used to do the "mass change" method 10-15%/week (15 to 20 gal /week on my 150) also. I found it created more instability in my system thank I liked so I went to smaller changes over the week...now I am using a Neptune DOS and doing continuous changes (about 2 gal/day---15 gal/week) This improved my take stability and my critters appeared to like this better. The theory being that smaller changes have less of an impact on the tank perimeters (pH, Salinity, Temp and other stuff effected by introducing "new water" I now only do bigger water changes if I am in trouble with (Nitrates, Phosphate or some other issue. My strategy is small changes in everything...Water change, dosing, any treatments for issues ETC.

Understand the concept completely. PRIOR to this phosphate low/ phosphate high/why are my euphyllia dying episode, I was doing NO water changes. This was my main reason for going Triton method. Because of my setup, WCs are pretty hard. Only reason I'm doing water changes now and running GAC is because I feel something is amiss, and I have high levels of lanthanum and lithium according to the ICP. I think I'll do weekly WCs for another month, get another ICP test and see where I am.

Back to the original point, if there truly were high PO4 levels (and actually in a worst case scenario, if they NEVER were that high), I very likely stripped them too much too fast. Again, the amount of phosphat-E I added should have completely eliminated the 0.25ppm or so I was reading much faster than it did, according to my Hanna. The directions note:
"Phosphate test kits may show a false-positive reading after aquarium has been treated; this is a result of the chemical mechanism by which phosphate test kits operate and does not indicate that the product has failed to perform its intended function. The higher the percentage of bound phosphate removed by filtration, the more accurate test kit readings will be."
I think my issue was I should have simply trusted the math, but I didn't. I initially DID see a decrease after using so I assumed that Hanna was reading accurately. Afterall, it says "...kits MAY show false-positive", the lower reading made me believe I was exempt from this. Once I saw the slight decrease, I assumed it was working and kept adding the stuff to get it under 0.05ppm, which I never did. The issue NOW is when can I trust the Hanna again? Hopefully the WCs and GAC will pull the Lanthanum out and I can ACCURATELY measure PO4 and have it match up with ICP testing.

Rick Mathew · Aug 13, 2019

cjpitt80 said:
Understand the concept completely. PRIOR to this phosphate low/ phosphate high/why are my euphyllia dying episode, I was doing NO water changes. This was my main reason for going Triton method. Because of my setup, WCs are pretty hard. Only reason I'm doing water changes now and running GAC is because I feel something is amiss, and I have high levels of lanthanum and lithium according to the ICP. I think I'll do weekly WCs for another month, get another ICP test and see where I am.

Back to the original point, if there truly were high PO4 levels (and actually in a worst case scenario, if they NEVER were that high), I very likely stripped them too much too fast. Again, the amount of phosphat-E I added should have completely eliminated the 0.25ppm or so I was reading much faster than it did, according to my Hanna. The directions note:
"Phosphate test kits may show a false-positive reading after aquarium has been treated; this is a result of the chemical mechanism by which phosphate test kits operate and does not indicate that the product has failed to perform its intended function. The higher the percentage of bound phosphate removed by filtration, the more accurate test kit readings will be."
I think my issue was I should have simply trusted the math, but I didn't. I initially DID see a decrease after using so I assumed that Hanna was reading accurately. Afterall, it says "...kits MAY show false-positive", the lower reading made me believe I was exempt from this. Once I saw the slight decrease, I assumed it was working and kept adding the stuff to get it under 0.05ppm, which I never did. The issue NOW is when can I trust the Hanna again? Hopefully the WCs and GAC will pull the Lanthanum out and I can ACCURATELY measure PO4 and have it match up with ICP testing.

The high lanthanum is most likely due to the Phosphate-E usage....I saw the same thing when I used it...Are you having algae or cyano problems? I actually don't worry about PO4 till it gets over .08 or so...BRS & WWC in their series on BRS TV stated a PO4 level between .02-.1ppm...you can look it up it is an interesting series...lots of good info. Here is a link

Search Results Template - Bulk Reef Supply

aquarium.bulkreefsupply.com

I would just let the system settle for a while...At least 1 month....As for trusting the Hanna Checker, Just like you I am very interested in the Accuracy of my test kits...not just the Hanna checkers but all of them. I do like you did and checked the PO4 tester out against a NIST Phosphate Std and found out it was (like you) withing 4-5% of the actual value. So I pretty much trust my results...I on occasion test 2-3 time just to validate the repeatability of the test or when I get a "crazy" number that makes no sense. FAUNA MARIN sells a reference solution...Not NIST Certified but ICP Validated (Which is another story all together)...Non the less it is a way to see how a test kit performs aginst a "known" STD ...Here is where I get it from

Multi-Reference Solution – CM Distributors

cm-distributors.com

Periodically I check my testers and test kits with this solution. (Calcium, Magnesium,Potassium, salinity, Conductivity
dKH,Nitrate and Phosphate)...It is just a good reference point.

Hope this helps

rick

foxt · Oct 9, 2019

Back to the original topic, I too have noticed that the Hanna 736 results are usually 3x what Triton ICP tells me. I am ordering icp-analysis test kits to see what they say ...

cjpitt80 · Oct 9, 2019

foxt said:
Back to the original topic, I too have noticed that the Hanna 736 results are usually 3x what Triton ICP tells me. I am ordering icp-analysis test kits to see what they say ...

Same here. Just got the email they're sending my sample off to Germany so.....We'll see. Last Hanna reading was 0.17ppm. Very interested in seeing how this correlates (or not) to what Triton comes back as. I haven't dosed Phosphat-E in a couple months now.

drawman · Oct 9, 2019

I've heard a lot of good things about the ELOS professional (not sure if that designation still exists) PO4 kit. I've also hated Red Sea test kits so it's Salifert for me for everything but PO4. I'm using a Hanna ULR but I think we all need to take these tests with a grain of salt and watch for algae growth and/or acro color. That said I don't use GFO currently so it's easy for me to say.

foxt · Oct 9, 2019

I've been testing two different systems with Triton, sending the Triton tests in on the same day and logging my own testing (Salifert, Hanna) for water taken as the same time as the samples.

Triton alk, Ca, Mg results are very close to my test results. Hanna 736 ULR P is about 3x what Triton P says for the four most recent tests on both systems (8 tests in total over three month period). I could see testing error on either my part or Triton's once or twice, but 8 tests? Two different lots for Hanna 736 reagents as well.

I know that Randy has explained that Triton's results might include anything with a P in it, but wouldn't that make their results potentially higher than Hanna, not the opposite?

I see that others have similar results, but then there are also others who report that Triton is in line with Hanna for them.

I'll do the icp tests at icp-analysis, and maybe even spring for an ELOS test kit, because this bugs me.

Rick Mathew · Oct 9, 2019

foxt said:
Back to the original topic, I too have noticed that the Hanna 736 results are usually 3x what Triton ICP tells me. I am ordering icp-analysis test kits to see what they say ...

I have been tracking my PO4 results since early this year vs. 3 different ICP providers...I gotten fairly decent agreement with the TRITON results up until this last one...here is a chart of the data...I am still digesting this and am currently doing a validation test using the HACH Phosphate Standard Solution...making up my own standards for testing. Will let you know the outcome..

foxt · Oct 9, 2019

Rick Mathew said:
I have been tracking my PO4 results since early this year vs. 3 different ICP providers...I gotten fairly decent agreement with the TRITON results up until this last one...here is a chart of the data...I am still digesting this and am currently doing a validation test using the HACH Phosphate Standard Solution...making up my own standards for testing. Will let you know the outcome..

Wow, thanks for that! With the 736, I log the raw P data vs. doing the calculation to convert to PO4. I think Triton just does the math to convert P to PO4 as well.

Converting your values to P, Hanna is within the +/- 5 PPB error and the ICP results except your last test - like you said, something looks really off on the Hanna with that one.

In my case, my last comparison tests (this week) had the Hanna 736 reporting P at 22ppb and Triton reporting it at 6.984. That's one set of samples from one tank. Same timeframe, other set of samples from the other tank, Hanna reported P at 16ppb and Triton came in at 4.563.

Samples were all mailed in the same USPS express mail envelope, so presumably they were subjected to the same environmental conditions along the way. Could something affect them in transit, like temp? That might not help with your results though, since your last Hanna is so much higher than all your others.

Rick Mathew · Oct 9, 2019

foxt said:
Wow, thanks for that! With the 736, I log the raw P data vs. doing the calculation to convert to PO4. I think Triton just does the math to convert P to PO4 as well.

Converting your values to P, Hanna is within the +/- 5 PPB error and the ICP results except your last test - like you said, something looks really off on the Hanna with that one.

In my case, my last comparison tests (this week) had the Hanna 736 reporting P at 22ppb and Triton reporting it at 6.984. That's one set of samples from one tank. Same timeframe, other set of samples from the other tank, Hanna reported P at 16ppb and Triton came in at 4.563.

Samples were all mailed in the same USPS express mail envelope, so presumably they were subjected to the same environmental conditions along the way. Could something affect them in transit, like temp? That might not help with your results though, since your last Hanna is so much higher than all your others.

You most welcome

I think that that last result was most likely an error on my part. At least that is my suspicion. Unfortunately I lost the retain of that sample could not repeat my work... I have always been suspicious that some of the parameters could be impacted by long transit times and varying environmental conditions. It might be worth conducting a series of experiments by storing a sample for an extended. Of time different environments to see if there are any differences in the result. Could be interesting!

I have found this test to be very sensitive to contamination. So I rinse the vial three times using the Hannity using the Hannah Distilled water and then before I run the test I rinse it out with the water to be tested. And I do not use this vial for any other tests.

foxt · Oct 9, 2019

Rick Mathew said:
I have found this test to be very sensitive to contamination. So I rinse the vial three times using the Hannity using the Hannah Distilled water and then before I run the test I rinse it out with the water to be tested. And I do not use this vial for any other tests.

Same here - I try to use the same vial for the 736 tester, leave it stored in RODI between tests, rinse it with tank water three times before testing, and fill with a verified 10ml syringe. I get pretty consistent and repeatable results with this tester, which makes me tend to want to trust it more, but others have said that the Triton results are more reliable, so I am scratching my head. Just for grins, just ran a test with a brand new cuvette, and it compares within tolerance with the test I ran this morning (18 vs. 16ppb).

Rick Mathew · Oct 9, 2019

foxt said:
Same here - I try to use the same vial for the 736 tester, leave it stored in RODI between tests, rinse it with tank water three times before testing, and fill with a verified 10ml syringe. I get pretty consistent and repeatable results with this tester, which makes me tend to want to trust it more, but others have said that the Triton results are more reliable, so I am scratching my head. Just for grins, just ran a test with a brand new cuvette, and it compares within tolerance with the test I ran this morning (18 vs. 16ppb).

Yes I know what you mean. I too feel very confident that my test results using the Hannah meter AR very good precision the question is always is it accurate. Do you have access to another meter? you could check it out versus another meter to see if there's a problem with your meter. I am going to run some tests versus some standard solutions that I makeup. just to see how close to meter actually is to these Solutions.

cjpitt80 · Oct 9, 2019

foxt said:
I know that Randy has explained that Triton's results might include anything with a P in it, but wouldn't that make their results potentially higher than Hanna, not the opposite?

Regarding that, I would also think the same which is why the results so confused me. I talked to this with Tim at Triton. See below.:
Tim,
Things have been going well so far! Had a little algae issue, but that seems to be cleared up now. In terms of PHOSPHATES, how does Triton ICP testing work? Specifically, does it measure TOTAL phosphates (bound and reactive) or just reactive? I've gotten some acros and I'm trying to reduce my phosphate levels using a product from Brightwell, Phosphat-E. The bottle says that after dosing, I can get a positive result from bound phosphates. My Hanna ULR phosphate reader was HIGHER after dosing so I want to check with Triton but I want to know exactly what it tests for.
Related, discarding some of the chaeto in the fuge should result in lower phosphates and nitrates as the chaeto regrows, correct? Also how "clean" should I keep the chaeto fuge in terms of sludge and slime algae on the bottom and sides of the glass?
Thanks a million!
Chris

TRITON Customer Service [email protected] via freshdesk.com

Fri, Jun 7, 12:51 PM

to me

Hi

The ICP tests for Phosphorus, both organic and inorganic.

Harvesting the algae will cause the nutrients to drop as it encourages new growth, there is a limit though as removing too much could cause a spike as there is not enough algae left to manage the system so little and often is better than removing large amounts in one go.

Some sludge/detritus is fine but if it starts to impact on the algae by reducing the flow/light then it should be removed.

Best Regards
Tim Caldwell
Communications Manager

foxt · Oct 9, 2019

Rick Mathew said:
Yes I know what you mean. I too feel very confident that my test results using the Hannah meter AR very good precision the question is always is it accurate. Do you have access to another meter? you could check it out versus another meter to see if there's a problem with your meter. I am going to run some tests versus some standard solutions that I makeup. just to see how close to meter actually is to these Solutions.

I only have the Hanna 774, which is less accurate, but also confirms the 736 within the spec'd tolerances. I will submit a couple of tests to another icp lab and see what I get back.

foxt · Oct 9, 2019

cjpitt80 said:
The ICP tests for Phosphorus, both organic and inorganic.

That should mean that Triton is higher than Hanna, right?

cjpitt80 · Oct 9, 2019

foxt said:
That should mean that Triton is higher than Hanna, right?

That's what my logic would state to me. However, my last Triton ICP test indicated PO4 level about 20x what my Hanna read. I was dosing the Phosphat-E at such a level that it could have really driven down the PO4 level, so we'll see in a few days what Triton says

Bramzor · Oct 9, 2019

My answer would be that phosphates in ICP are not that correct. Reason: I had an ICP test on RO water which I'm sure of did not contain any phosphates but for some reason, ICP did notice some. Was a new RO system with 2 DI filters and a Silicate resin so I'm sure there wouldn't be any phosphates in the sample.

cjpitt80 · Oct 9, 2019

Bramzor said:
My answer would be that phosphates in ICP are not that correct. Reason: I had an ICP test on RO water which I'm sure of did not contain any phosphates but for some reason, ICP did notice some. Was a new RO system with 2 DI filters and a Silicate resin so I'm sure there wouldn't be any phosphates in the sample.

In my situation, I was using the Brightwell Lanthanum stuff to lower phosphates. On the bottle it says it can cause a "false positive" reading. INITIALLY I saw a lower number with my Hanna, so (like a dummy) I kept dosing. I could never get below about 0.10ppm. I noticed my euphyllia looking like crap and sent in a ICP sample. I also checked with my Hanna the same sample which was 0.14ppm. Triton ICP came back almost 20x LESS at 0.0068ppm or so. Going by the DOSING on the Brightwell bottle, I SHOULD have been down somewhere to those levels. Lowest Hanna reading I got was something like 0.10ppm

cjpitt80 · Oct 10, 2019

Well.. New ICP test results are in. Still reading lower than Hanna. Hanna 0.17ppm vs Triton ICP 0.023ppm. So, yeah......? Triton is about 7.5x higher
October '19 ICP reading