Fauna Marin MultiReference solution - I'm confused

[Rick Mathew]

Thanks for so rigorously showing this! Any chance you plan to test the nitrate checker?

Here is the test of the LR Nitrate Checker...Have not done the HR

https://www.reef2reef.com/threads/h...trite-interference.783628/page-2#post-8552481

 

[taricha]

Thanks for so rigorously showing this! Any chance you plan to test the nitrate checker?

Rick's got you covered on that one!

Here is the test of the LR Nitrate Checker...Have not done the HR

https://www.reef2reef.com/threads/h...trite-interference.783628/page-2#post-8552481

 

[Rick Mathew]

Here is my batch of the Fauna Marin Multi-Reference Standard

Based on this I should expect a P measurement some where between 65-70

Below are the results of the P measurement on the HI-736

First measurement --1.0 (.005 PO4)
Second measurement--- 4.0 (.012 PO4)
Third Measurement----3.0 (.009 PO4)

This is way off...The sample is clear with no visible signs of algae...Not sure what to make of it ...will retest tomorrow along with the NO3

Rick

 

[Chrisv.]

Wow. @Rick Mathew and @taricha, what fantastic work. It's so nice to see people with replicates and error bars.

 

[Rick Mathew]

Replication of PO4 test on my Fauna Marin Standard with HI-736 Phosphorous Checker
Fauna Marin Reported Levels
PO4---.2ppm (Actually .195ppm by weight)
NO3---10.0ppm (Actually 9.75 by weight)

Previous results:
First measurement---------1.0ppb P--- (.005ppm PO4)
Second measurement--- 4.0ppb P--- (.012ppm PO4)
Third Measurement-------3.0ppb P (.009ppm PO4)
Replication Today:---------6.0ppb P (.018 ppm PO4)


Nitrate Measurement ( My method using Red Sea Reagents and HI-764 Nitrite Checker)

10.7 ppm

So it looks as if the NO3 is reasonable but the PO4 is way off...At least on my test. I would also like to note that ICP measurements are not the necessary the best at measuring P from my experience:)

 

[Chrisv.]

I really like the idea of having a single standard that can be used for many positive controls. Is there one that works better?

 

[Rick Mathew]

I really like the idea of having a single standard that can be used for many positive controls. Is there one that works better?

There are several providers of standard solutions, some provide multi-element standards. They tend to be expensive and to find one that has the element combination we might be interested in is challenge...

Here are a couple I have looked at

https://www.hach.com/quick.search-quick.search.jsa?keywords=standard+solutions
https://www.sigmaaldrich.com/US/en/...stry/calibration-qualification-and-validation
https://www.agilent.com/en/product/chemical-standards/elemental-analysis/single-element-standards
https://highpuritystandards.com/products/simulated-sea-water-standard-in-2-hno3/ ----This one would be a good one but it is $224 for 100mL

There are most likely others---I have used single element standards (NO3, P, I, Ca, Mg Etc.) to do my Test Development work.

 

[Randy Holmes-Farley Verified Community Expert]

These folks make high end seawater standards for scientists:

https://osil.com/product-category/seawater-standards-salinometers/

 

[Rick Mathew]

These folks make high end seawater standards for scientists:

https://osil.com/product-category/seawater-standards-salinometers/

Thanks I will check it out

 

[Malcontent]

I have some 100 mg/L NO3-N standard. I'm thinking 1 mL of that, 9 mL of RO/DI and 462 mg of Instant Ocean salt.

 

[Rick Mathew]

I have some 100 mg/L NO3-N standard. I'm thinking 1 mL of that, 9 mL of RO/DI and 462 mg of Instant Ocean salt.

What level of NO3 are you targeting?

 

[Malcontent]

What level of NO3 are you targeting?

I figure a ten-fold dilution would be easiest so 44.3 mg/L NO3-. It's squarely within the range of the HI782 and a Hach test I want to try in saltwater.

 

[Rick Mathew]

I figure a ten-fold dilution would be easiest so 44.3 mg/L NO3-. It's squarely within the range of the HI782 and a Hach test I want to try in saltwater.

That makes sense...look forward to the outcome

Rick

 

[R33f_Hacker]

Does anyone know what the shelf life is on the bottle? Trident calibration solution says its only good for 8 hours after opening. Thanks

 

[Randy Holmes-Farley Verified Community Expert]

Does anyone know what the shelf life is on the bottle? Trident calibration solution says its only good for 8 hours after opening. Thanks

Are you referring to a Trident pH solution?

pH solutions are impacted by atmospheric CO2. No other reefing standards have such issues, although all can be impacted by evaporation, user contamination, or algae growth in them.

 

[R33f_Hacker]

Are you referring to a Trident pH solution?

pH solutions are impacted by atmospheric CO2. No other reefing standards have such issues, although all can be impacted by evaporation, user contamination, or algae growth in them.

Not for PH. Trident does Alk, Ca, mg
I figure they say 8 hours bc the alk will drop once opened to air. Not sure if that's true or not. Thanks Randy

 

[areefer01]

Are you referring to a Trident pH solution?

pH solutions are impacted by atmospheric CO2. No other reefing standards have such issues, although all can be impacted by evaporation, user contamination, or algae growth in them.

No, I don't believe so. They are talking about the Trident Calibration solution that is in the reagent box.

Not for PH. Trident does Alk, Ca, mg
I figure they say 8 hours bc the alk will drop once opened to air. Not sure if that's true or not. Thanks Randy

You are correct. Neptune says that it is only good for 8 hours after using (opening, calibrating, etc). With that out of the way what I do with mind after calibration is to cap it, grab a sharpie and note date, time on the bottle, then store it in a cool dry place. I will use it later should I need to run a quick sanity check in a couple back to back tests are out of my normal ranges. I'll rotate through the bottles as I go through reagents. Note: I do not use it to calibrate again but only as a reference. And I do not combine them.

I also keep a couple bottles of Fauna Marin multi reference solution on hand. Similar approach in that I note the date, time, on the bottle after first use. I emailed them and the reply I got back with their product is that it is good for 6 months after opening assuming stored properly. It is good to have on hand. I will use this to calibrate should I need a quick run.

About the only other thing I do is when I do tests using reference solution I do take a warm cloth and wipe off the Trident's sample line. I can't say that is 100% cleaning it but it makes me feel good and I think it is doing something.

 

[Randy Holmes-Farley Verified Community Expert]

Not for PH. Trident does Alk, Ca, mg
I figure they say 8 hours bc the alk will drop once opened to air. Not sure if that's true or not. Thanks Randy

What alk and calcium does it claim to be?

It might be a seawater mimic that is made at extra low pH to try to prevent calcium carbonate precipitation, and loss of CO2 to the air may raise the pH and risk precipitation.

 

[areefer01]

What alk and calcium does it claim to be?

It might be a seawater mimic that is made at extra low pH to try to prevent calcium carbonate precipitation, and loss of CO2 to the air may raise the pH and risk precipitation.

Numbers may vary a bit between lot numbers but here is an image from a bottle. Left bottle is Neptune Trident. Right is Fauna Marin. Little blurry but you see the lot number, dkh, ca, and mg with note for 8 hours after use.

As I noted above I use it once to calibrate as that is its intended use. After that I cap it, mark date and time, and store in a cool dry area. At that point I use it only for ad-hoc reference. Each time I've done that it has worked well for me to spot check.

Due to lot numbers I do not combine. Also it is a small bottle so not worth worrying much over and keep a bottle of Fauna Marin. You get the idea.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, I personally do not think it's a good idea to combine alk and calcium standards into one solution because of issues of potential precipitation after manufacture