How do you ensure accurate WC testing?

[Fishjayfonz]

Hey all,

Curious to see how others test their systems to ensure accurate results for example by running multiple series, standards, brands etc.

Currently I use the AF kits for Ca & Mag, and Hanna Checkers for Alk & PO4. Recently I've been trying to fine tune my testing methods to ensure the numbers I'm getting are reliable. I'll check readings by running Ca & Mag using Salifert kits as well as running samples against a standard provided in the AF kits for Ca & Mag. I'll also send off a monthly ICP when I can.

Lately I have become distrusting of the ULR Hanna checker for PO4 as it's readings conflict with ICP (~0.30 checker vs. 0.02 ICP), so finding a way to reliably test for PO4 is my priority right now, without having to rely on external ICP testing.

Would love to hear your guys methods and how you drive for precision!

Fair Winds & Happy Reefing,

Jason

 

[Rick Mathew]

I have made standards in the past but have found that they tend to drift in readings quite a lot over a period of a few weeks. ICP we use Triton and am fairly confident in those results as our Iodine is also in check. Would like those results to agree with our in house testing though

Yes, I also have found the same thing. Most commercially available standards are stabilized with Nitric or Hydrochloric acid. Also standard practice in water sampling for testing that are to be stored is to acidify the sample .

 

[Rick Mathew]

Three of us (@Dan_P, @taricha and I) decided to embark on a project that might answer some of the questions that are posed in this thread. Here is a sneak peak at the work. There will be more details to come later.
OVERVIEW
Two large samples were prepared from a fresh mix of Red Sea salt. One was unaltered and the second was spiked using NIST traceable standards (See Picture Below). The samples were then divided among three testers who would do standard hobby grade tests for individual elements. The elements were calcium, copper, iodine, iron, magnesium, potassium, phosphorus and silica. In addition the samples were sent to 4 different ICP providers. All of the data is now being tabulated and analyzed. But here is a sneak peek at two of the elements, iodine and phosphorus. The goal of the project was to see how much of the spiked elements each of the testers picked up in their testing.

There is a lot more detail to this work but it is not ready for publication as of yet. Because this thread is right down the center lane of the questions that we were asking in this project we decided to push out some of the results. There will be lots more to come later, But this will give you a flavor of what the data is looking like....No conclusions as of yet stay tuned!

SOME RESULTS
SPIKING LEVELS----IODINE .06 PPM------ PHOSPHOROUS 20 PPB

SPIKING LEVELS----IODINE .06 PPM PHOSPHOROUS 20 PPB

NIST TRACEABLE STANDARD

 

[Dan_P]

Three of us (@Dan_P, @taricha and I) decided to embark on a project that might answer some of the questions that are posed in this thread. Here is a sneak peak at the work. There will be more details to come later.
OVERVIEW
Two large samples were prepared from a fresh mix of Red Sea salt. One was unaltered and the second was spiked using NIST traceable standards (See Picture Below). The samples were then divided among three testers who would do standard hobby grade tests for individual elements. The elements were calcium, copper, iodine, iron, magnesium, potassium, phosphorus and silica. In addition the samples were sent to 4 different ICP providers. All of the data is now being tabulated and analyzed. But here is a sneak peek at two of the elements, iodine and phosphorus. The goal of the project was to see how much of the spiked elements each of the testers picked up in their testing.

There is a lot more detail to this work but it is not ready for publication as of yet. Because this thread is right down the center lane of the questions that we were asking in this project we decided to push out some of the results. There will be lots more to come later, But this will give you a flavor of what the data is looking like....No conclusions as of yet stay tuned!

SOME RESULTS
SPIKING LEVELS----IODINE .06 PPM------ PHOSPHOROUS 20 PPB

SPIKING LEVELS----IODINE .06 PPM PHOSPHOROUS 20 PPB

NIST TRACEABLE STANDARD

And Rick will also reveal the blood, sweat, and tears he shed to acquire these gold standard standards that made the study possible :)

 

[Rick Mathew]

And Rick will also reveal the blood, sweat, and tears he shed to acquire these gold standard standards that made the study possible :)

Persistence pays...:)

 

[Randy Holmes-Farley]

Thank you folks for starting to post this nice study. :)

 

[Tcook]

Three of us (@Dan_P, @taricha and I) decided to embark on a project that might answer some of the questions that are posed in this thread. Here is a sneak peak at the work. There will be more details to come later.
OVERVIEW
Two large samples were prepared from a fresh mix of Red Sea salt. One was unaltered and the second was spiked using NIST traceable standards (See Picture Below). The samples were then divided among three testers who would do standard hobby grade tests for individual elements. The elements were calcium, copper, iodine, iron, magnesium, potassium, phosphorus and silica. In addition the samples were sent to 4 different ICP providers. All of the data is now being tabulated and analyzed. But here is a sneak peek at two of the elements, iodine and phosphorus. The goal of the project was to see how much of the spiked elements each of the testers picked up in their testing.

There is a lot more detail to this work but it is not ready for publication as of yet. Because this thread is right down the center lane of the questions that we were asking in this project we decided to push out some of the results. There will be lots more to come later, But this will give you a flavor of what the data is looking like....No conclusions as of yet stay tuned!

SOME RESULTS
SPIKING LEVELS----IODINE .06 PPM------ PHOSPHOROUS 20 PPB

SPIKING LEVELS----IODINE .06 PPM PHOSPHOROUS 20 PPB

NIST TRACEABLE STANDARD

Are you also going to look at how Trident and Ion Director compares to ICP and your manual testers?

 

[Rick Mathew]

Are you also going to look at how Trident and Ion Director compares to ICP and your manual testers?

Interesting question...never thought about that...That could be an interesting evaluation...Will ponder that...Thanks

 

[Tcook]

Interesting question...never thought about that..

I think most hobbyists would like to know which automatic tester, if any, stacks up to a well performed manual test. I have found my Trident may be fairly consistant but could never get it closer than 0.8-1.2 dkh off from a good manual test. Maybe that is within its accuracy and I’m hoping for too much.

 

[Rick Mathew]

I think most hobbyists would like to know which automatic tester, if any, stacks up to a well performed manual test. I have found my Trident may be fairly consistant but could never get it closer than 0.8-1.2 dkh off from a good manual test. Maybe that is within its accuracy and I’m hoping for too much.

Will have a look at what it might take..thanks again

Rick

 

[Rick Mathew]

Hey all,

Curious to see how others test their systems to ensure accurate results for example by running multiple series, standards, brands etc.

Currently I use the AF kits for Ca & Mag, and Hanna Checkers for Alk & PO4. Recently I've been trying to fine tune my testing methods to ensure the numbers I'm getting are reliable. I'll check readings by running Ca & Mag using Salifert kits as well as running samples against a standard provided in the AF kits for Ca & Mag. I'll also send off a monthly ICP when I can.

Lately I have become distrusting of the ULR Hanna checker for PO4 as it's readings conflict with ICP (~0.30 checker vs. 0.02 ICP), so finding a way to reliably test for PO4 is my priority right now, without having to rely on external ICP testing.

Would love to hear your guys methods and how you drive for precision!

Fair Winds & Happy Reefing,

Jason

Jason...This is a most worthy pursuit! To fine tune your testing methods to get more accuracy and precision is IMO very much worth spending time on...it will give you more peace of mind and help you make better decision for your reef system...more importantly your "critters" :)

Below are 4 links to some articles I wrote some time ago that addresses this very issue...You might find some helpful hints.

GETTING IT RIGHT! ---MAKE TESTING COUNT BY USING A QUALITY SYSTEM APPROACH

GETTING IT RIGHT! ---MAKE TESTING COUNT BY USING A QUALITY SYSTEM APPROACH INTRODUCTION All of us want healthy and thriving Reef Tanks. This necessarily means excellent water quality. So I ask myself. How do I know the quality of my water...

www.reef2reef.com

PART 2 -GETTING IT RIGHT--MAKE TESTING COUNT BY USING A QUALITY SYSTEM APPROACH---COLORIMETRIC VISUAL TESTING

PART 2-----COLORIMETRIC VISUAL TESTING METHODS (The Chemistry) As we covered in Part 1 in the “Understanding Errors” section, the visual testing method consists of essentially two steps, Evaluation and Assessment. Evaluation is the test...

www.reef2reef.com

Advanced Topic - PART 3 -----GETTING IT RIGHT---COLORIMETRIC VISUAL TESTING METHODS (What We See)

PART 3 -----COLORIMETRIC VISUAL TESTING METHODS (What We See) SOURCES OF ERROR IN THE ASSESSMENT PROCEDURE Next we turn to the second component of our testing protocols and that is the ASSESSMENT…What do we see and how do we interpret the...

www.reef2reef.com

PART 4 "GETTING IT RIGHT" COLORIMETRIC INSTRUMENTAL TESTING METHODS (DIGITAL)

PART 4 "GETTING IT RIGHT" COLORIMETRIC INSTRUMENTAL TESTING METHODS (DIGITAL) As we turn our attention to the use of digital testers (Colorimeters) such as the HANNA CHECKER, most of the same elements necessary for good precision and accuracy...

www.reef2reef.com

Rick

 

[taricha]

I think most hobbyists would like to know which automatic tester, if any, stacks up to a well performed manual test. I have found my Trident may be fairly consistant but could never get it closer than 0.8-1.2 dkh off from a good manual test.

That would be a fun exercise. Having not ever messed with the auto-testers in person, I don't have a good feeling for whether what's being measured directly is doable at the same, better or worse precision/repeatability than what a hobbyist would do.

 

[Rick Mathew]

That would be a fun exercise. Having not ever messed with the auto-testers in person, I don't have a good feeling for whether what's being measured directly is doable at the same, better or worse precision/repeatability than what a hobbyist would do.

We would need several volunteers to pull this off...

 

[reefluvrr]

any status update on findings?