Phosphate: ICP test vs Hanna tester discrepancy

[AndrewBrusca]

Hi Everyone,

I have a 225 gallon mixed reef with Acros and just did my first ICP test. I was surprised to see it referenced my phosphates as being “low” at 0.3.

I simultaneously tested with my Hanna tester multiple times and got results like 0.11 - 0.18. It has been consistent at this rate per Hanna for roughly a year, occasionally going down to 0.9.

I know Hanna kits arent always consistent. And I understand stability and staying within a consistent range is most important. But based on the ICP and Hannah results, should I be looking at raising or lowering nutrients?

Do Hannah kits need to be replaced periodically? Or are they just inconsistent

Thanks for any help,
Andrew

 

[rowenaad]

do you meant to say 0.03 from ICT and 0.09 occasionally from hanna? Im about to send in my first sample for ICY but i have read this discrepancy being consumption on its way by maybe bacteria in the water

 

[AndrewBrusca]

do you meant to say 0.03 from ICT and 0.09 occasionally from hanna? Im about to send in my first sample for ICY but i have read this discrepancy being consumption on its way by maybe bacteria in the water

Yes apologies for not clarifying. I thought i was running 0.09+ based on Hanna tester. Then the ICP showed 0.3.

So based on consumption would you be more inclined to treat the ICP as the more accurate number?

 

[Dan_P]

Hi Everyone,

I have a 225 gallon mixed reef with Acros and just did my first ICP test. I was surprised to see it referenced my phosphates as being “low” at 0.3.

I simultaneously tested with my Hanna tester multiple times and got results like 0.11 - 0.18. It has been consistent at this rate per Hanna for roughly a year, occasionally going down to 0.9.

I know Hanna kits arent always consistent. And I understand stability and staying within a consistent range is most important. But based on the ICP and Hannah results, should I be looking at raising or lowering nutrients?

Do Hannah kits need to be replaced periodically? Or are they just inconsistent

Thanks for any help,
Andrew

ICP measures total phosphorous, Hanna measures only phosphate. The two measurement methods may never agree even when ICP is measuring onlyphosphate.

Stick with Hanna to measure phosphate which is the chemical species most likely having influence on coral and algae growth. Total phosphorous might not be relevant.

 

[AndrewBrusca]

ICP measures total phosphorous, Hanna measures only phosphate. The two measurement methods may never agree even when ICP is measuring onlyphosphate.

Stick with Hanna to measure phosphate which is the chemical species most likely having influence on coral and algae growth. Total phosphorous might not be relevant.

Thanks for explaining that. I attached a screenshot of the ICP teat to this reply, it references phosphorus and phosphate, does that change anything?

 

[Reefer1978]

Check out my thread, plenty of explanations there as I ran into the same confusion you have: https://www.reef2reef.com/threads/phosphate-testing.1120956/#post-13738146

Executive summary:
* ICP tests for all forms of phosphorous, and then converts to Phosphate
* Hannah ULR PPB meter tests Phosphate, but converts to phosphorous (because why would we make things easy on reefers) requiring that stupid chart to convert back

 

[Dan_P]

Thanks for explaining that. I attached a screenshot of the ICP teat to this reply, it references phosphorus and phosphate, does that change anything?

The ICP company may be measuring phosphate with a chemical test and calculating phosphorous or measuring phosphorous and calculating phosphate. Try to find out.

Normally, ICP results rarely reproduce hobby test results. The discrepancy may be related to how the sample changes in transit. Normally, samples shipped for ICP’s are acidified to stabilize the sample.. Hobby ICP companies skip this step. Best to ignore ICP phosphorous result.

 

[RelaxingWithTheReef]

The ICP company may be measuring phosphate with a chemical test and calculating phosphorous or measuring phosphorous and calculating phosphate. Try to find out.

Normally, ICP results rarely reproduce hobby test results. The discrepancy may be related to how the sample changes in transit. Normally, samples shipped for ICP’s are acidified to stabilize the sample.. Hobby ICP companies skip this step. Best to ignore ICP phosphorous result.

FWIW – The phosphate results I received from Oceamo have typically matched my calibrated DIY test within +-10%. Their sampling kit includes a filter and a liquid “stabilizer.”

Christoph has always been available to answer questions, and I consider their ICP-MS test the gold standard of aquarium ICP testing,

“But our expertise does not end with ICP-MS. We combine this leading technology with a wide range of established methods such as ICP-OES, ion chromatography, as well as specialized measurements for salinity, alkalinity and phosphate.”

“Salinity is measured with a conductivity probe and alkalinity (KH) is determined titrimetrically. In addition, we measure phosphate using a sensitive photometric method, which means that this important parameter is determined precisely.”

https://en.oceamo.com/analysen/

 

[X-37B]

Hi Everyone,

I have a 225 gallon mixed reef with Acros and just did my first ICP test. I was surprised to see it referenced my phosphates as being “low” at 0.3.

I simultaneously tested with my Hanna tester multiple times and got results like 0.11 - 0.18. It has been consistent at this rate per Hanna for roughly a year, occasionally going down to 0.9.

I know Hanna kits arent always consistent. And I understand stability and staying within a consistent range is most important. But based on the ICP and Hannah results, should I be looking at raising or lowering nutrients?

Do Hannah kits need to be replaced periodically? Or are they just inconsistent

Thanks for any help,
Andrew

My egg is 7 years old and has been quite accurate for po4.
Last Icp
My po4 .055
Icp po4 .06
It has always been close to all icp results that I can count on the number to be accurate.

 

[CHSUB]

I have done three ICPs this year and all were the same as my Hanna Checker, which was a pleasant surprise. So maybe your testing is flawed or your ICP company is subpar. For reference I’m using FM for ICP. Acceptable level is also opinion, as my ICP company states .03 is normal and I agree.

understand stability and staying within a consistent range is most important

Also worth discussing is I don’t think consistency is very important and a hobby observation. Natural coral reefs go from low levels of nutrients to high levels during deep water upwellings and rain season run offs and just as quick those excess nutrients get flushed into the abyss. Imo, just another hobby myth. Reef requires and do best with low but available nutrients, fluctuations imo are less important.

 

[KStatefan]

I have had the same experience as @CHSUB when comparing my Hanna test with the results Oceamo reports on ALk, Nitrate and Phosphate.

 

[Dan_P]

FWIW – The phosphate results I received from Oceamo have typically matched my calibrated DIY test within +-10%. Their sampling kit includes a filter and a liquid “stabilizer.”

Christoph has always been available to answer questions, and I consider their ICP-MS test the gold standard of aquarium ICP testing,

“But our expertise does not end with ICP-MS. We combine this leading technology with a wide range of established methods such as ICP-OES, ion chromatography, as well as specialized measurements for salinity, alkalinity and phosphate.”

“Salinity is measured with a conductivity probe and alkalinity (KH) is determined titrimetrically. In addition, we measure phosphate using a sensitive photometric method, which means that this important parameter is determined precisely.”

https://en.oceamo.com/analysen/

Thank you for the clarification and setting the record straight.

 

[Reefer1978]

Deleting - posted in the wrong thread...

 

[Reefer1978]

Deleting - posted in the wrong thread...

 

[PR_nano]

I done a few ATI ICP test and below are my comparison with home test kit and which one. I find phosphate to be pretty accurate I use the the Hanna Phosphorus ULR (HI736)

ICP results 1
Salinity 36.03
Alk 8.14
Ca 559.3
Mg 1274
N03 10.72
P04 .02

My results 1
Sg (Milwaukee)1.028
Alk (Hanna) 8.4
Ca (Salifert) 500+
Mg (Salifert) 1500
N03 (Hanna) 7.5
P04 (Hanna) .02

Second test

ATI	Home test kits
Alk 8.19	8.1
Ca 478.6	465
Mg 1188	1395
NO3 15.44	14.3
PO4 .13	.11

Third test

ATI	Home test kits
Alk 7.29	7.6
Ca 418.4	420
Mg 1328	1350
NO3 3.99	2.9
PO4 .04	.04

 

[AndrewBrusca]

I done a few ATI ICP test and below are my comparison with home test kit and which one. I find phosphate to be pretty accurate I use the the Hanna Phosphorus ULR (HI736)

ICP results 1
Salinity 36.03
Alk 8.14
Ca 559.3
Mg 1274
N03 10.72
P04 .02

My results 1
Sg (Milwaukee)1.028
Alk (Hanna) 8.4
Ca (Salifert) 500+
Mg (Salifert) 1500
N03 (Hanna) 7.5
P04 (Hanna) .02

Second test

ATI	Home test kits
Alk 8.19	8.1
Ca 478.6	465
Mg 1188	1395
NO3 15.44	14.3
PO4 .13	.11

Third test

ATI	Home test kits
Alk 7.29	7.6
Ca 418.4	420
Mg 1328	1350
NO3 3.99	2.9
PO4 .04	.04

Okay so I used ATI ICP and it sounds like my discrepancy is too large.

Tbh i feel like my hanna test kid always gives varying results. I’m tempted to buy a new hanna phosphates tester.

If i do two hanna phosphates tests. One is always different than the next even when taken within 5 minutes of the other.

I think I need to submit another ICP test for more confidence and i may also buy a new hanna. Or maybe a salifert phosphates for more info.

I dont think i am going to attempt to increase or decrease phosphates as a result of this initial testing as the confidence is too low atm

 

[mook1178]

which means that this important parameter is determined precisely.”

And what is that precision? Such a vague statement made to sound like it means something, when it actually means nothing. Every measurement is made precisely, based on the measurement precison.

 

[CHSUB]

Okay so I used ATI ICP and it sounds like my discrepancy is too large.

Tbh i feel like my hanna test kid always gives varying results. I’m tempted to buy a new hanna phosphates tester.

If i do two hanna phosphates tests. One is always different than the next even when taken within 5 minutes of the other.

I think I need to submit another ICP test for more confidence and i may also buy a new hanna. Or maybe a salifert phosphates for more info.

I dont think i am going to attempt to increase or decrease phosphates as a result of this initial testing as the confidence is too low atm

How well are you at using a Hanna? I ask because I first started using one in 2012 and my process was not that good. It wasn’t until I watched a video by someone about the packs, timing and cleaning of the vials that I started getting consistent results.

 

[Christoph]

And what is that precision? Such a vague statement made to sound like it means something, when it actually means nothing. Every measurement is made precisely, based on the measurement precison.

What this means is that phosphate is measured using a photometric method specific for phosphate, taken from a chemically stabilized and filtered sample. This is very different from measuring total phosphorus by ICP and then back-calculating a phosphate level from that result — the latter is affected by all phosphorus species, not just phosphate.

I agree that the original sentence was not ideally translated from German. We’ll improve it during our next website update.

Best regards, Christoph

 

[AndrewBrusca]

How well are you at using a Hanna? I ask because I first started using one in 2012 and my process was not that good. It wasn’t until I watched a video by someone about the packs, timing and cleaning of the vials that I started getting consistent results.

I think i do a good job with hanna phosphate testing, I take a couple different precautions for consistency as follows:

After i use vials i wash them out rather quickly with tap water. (Not rodi bc it’s not convenient.)

I also make sure to wipe the vials carefully before using.

I ensure the amount of water in the vial is the same and consistent each time.

When cutting open reagent packages, i make sure to get as much out of it as possible..

Very consistent mixing motion once reagent is added.

I test twice consecutively every time i test phosphates.

I’ve found that i tend to get different results every time. Usually results are .07-.09 and something like .13-.15.

Theyre not insanely discrepant so i generally treat the phosphate by whatever number is in the middle of the two tests….

Is there anything significant i may be missing based on that? I’m considering buying a new phosphate tester bc ive had this one for 4+ years used relatively often and maybe it’s having issues…