ICP-MS measurement of Seawater Certified Reference Material

[Reefahholic]

I would also add that I think most icp companies are not measuring inorganic phosphate, even if they seem to report it. They are just taking the phosphorus value from icp and multiply by 3.06 to get phosphate.

Yeah I think most are taking the one value and calculating the other.

So let me pick your brian more Randy while I got you here. Is there a way to dose phosphorus to get it up. I’m reading zero on my “phosphorus” ULR and I’m currently dosing 0.06 ppm Phosphate daily (which is a lot!)I don’t want to over do it with dosing TSP (Na3PO4) or pollute the tank with food. I typically go slow…but in this situation time is valuable, because the beginning of Dino’s are appearing on the rocks.

P = 0 (despite all the dosing) 60 x 0.1 (0.06 ppm) daily

Could this Phosphorus reading above be false and lead me to overdosing TSP / Trisodium Phosphate?

N = 4

Can you get two different readings from a “Phosphorus” ULR meter vs “Phosphate” ULR meter? I was under the impression that they both report Phosphate but just choose to report the values differently ppb (Phosphorus) ppm (Phosphate).

 

[Reefahholic]

you can dose organic or inorganic phosphate, if you want to dose, but must folks elect to dose inorganic phosphate, such as sodium phosphate.

So TSP would be inorganic Phosphate. Would a Phosphorus supplement like Seacheam Flourish be considered organic?

Also, will our inorganic dosing of TSP / Trisodium Phosphate raise phosphorus levels or only phosphate levels (is there a difference) and what is the best way to measure that so we don’t over dose the system? I don’t want to keep dosing TSP if it’s polluting the tank and my Phosphorus ULR cannot detect it.

 

[PSXerholic]

This is from the ICP OES, from my recently started Demo tank.

 

[PSXerholic]

This is from the ICP MS testing, see Chris comment in that.

 

[PSXerholic]

Here the secret of what ATI does ;-) They all do not truly measure elemental free P to my knowledge.

 

[Reefahholic]

My question for everybody:

Are there two different products for dosing?

Phosphate products like LoudWolf Sodium Phosphate or Trisodium Phosphate

Or….

Phosphorus products like Seachem Flourish.

Do these both dose “Phosphate” back to the system or is one dosing “phosphate” and the other dosing “phosphorus?”

I was under the impression that you cannot dose phosphorus? Can Seachem Flourish (which is apparently phosphorus) be dosed to raise “phosphorus” or is this misinformation by that company?

Can phosphorus levels be raised (by X product) and will it reflect on ICP-OES or ICP-MS?

Is there a phosphorus element that we should be using or is it essentially all PHOSPHATE.?

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Randy Holmes-Farley​

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RabidDragon said:
Source of confusion: I was concerned that my Hanna checker was specifically testing for phosphate and I was dosing "phosphorous" and was potentially not able to test for what I was adding and possibly over dosing. While investigating how I could resolve this testing issue today I discovered that there is also a Hannah phosphorous URL checker AND that ATI's website talks about phosphate and not phosphorous while displaying a picture of the exact bottle I'm using to dose my tank with.... So now I'm not clear what I'm actually adding to my tank or what to use to test it.

You are not dosing phosphorus. It is not stable in water and burns when wet. It's a weapon of war (e.g., white phosphorus grenades).

The Hanna is detecting inorganic phosphate, regardless of how it chooses to report the data (some are in ppb phosphorus, some in ppm phosphate).

ICP detects only the atom P, and it may come from organic forms of phosphate (such as DNA, phospholipids, etc.) as well as inorganic phosphate.

 

[PSXerholic]

My question for everybody:

Are there two different products for dosing?

Phosphate products like LoudWolf Sodium Phosphate or Trisodium Phosphate

Or….

Phosphorus products like Seachem Flourish.

Do these both dose “Phosphate” back to the system or is one dosing “phosphate” and the other dosing “phosphorus?”

I was under the impression that you cannot dose phosphorus? Can Seachem Flourish (which is apparently phosphorus) be dosed to raise “phosphorus” or is this misinformation by that company?

Can phosphorus levels be raised (by X product) and will it reflect on ICP-OES or ICP-MS?

Is there a phosphorus element that we should be using or is it essentially all PHOSPHATE.?

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You are not dosing phosphorus. It is not stable in water and burns when wet. It's a weapon of war (e.g., white phosphorus grenades).

The Hanna is detecting inorganic phosphate, regardless of how it chooses to report the data (some are in ppb phosphorus, some in ppm phosphate).

ICP detects only the atom P, and it may come from organic forms of phosphate (such as DNA, phospholipids, etc.) as well as inorganic phosphate.

Do not open the box !!!! Ahhhhh too late ;-)

 

[Reefahholic]

We got all the major players on the thread now…and I’m honestly dying to get some answers that we all agree on.

There is no doubt this is a very confusing and complicated topic.

Not only that, even the pros have a difficult time managing phosphate. Or is it phosphorus? Or is it both?

Do we really know? Not even the ICP’s can directly measure both elements. They measure one and calculate the other. Maybe OCEAMO changed that?


So many products on the market that are split between phosphate and phosphorus.

 

[PSXerholic]

When your looking into the Box, you need to understand the testing of P/Po4 first a bit better.
I always found the information from Hach very informative for most people to read through.
Also talks a bit about from an engineering perspective about the different types of Phosphates.

Have a look.

https://www.hach.com/asset-get.download.jsa?id=50989301315

 

[Reefahholic]

I’m gonna be really ticked if I’ve been dosing Trisodium Phosphate and using the Hanna ULR phosphorus to try and detect it if it really cannot detect it. It’s somehow being working for years if that is the case.

I’m getting Zero’s on both Hanna Phosphate ULR and Phosphorus ULR…

Sooooo….

ICP below:

Analysis result

ATI Aquaristik - Lab

lab.atiaquaristik.com

 

[Reefahholic]

And personally I don’t think the Hanna Phosphorus is actually measuring Phosphorus. It’s just measuring lower in Parts per Billion (ppb) while all the other Hanna’s read in Parts per Million (ppm).


Hanna Phosphate High Range HI717

Range: 0.0 to 30.0 ppm



Hanna Phosphate Low Range HI713

Range: 0.00 to 2.50 ppm



Hanna Phosphate ULR HI774

Range: 0.00 to 0.90 ppm



Hanna Phosphorus ULR HI736

Range: 0 to 200 ppb

 

[taricha]

This is from the ICP OES, from my recently started Demo tank.

Nice. PO4 chemical test lines up close to the expectation by taking the P ICP test and multiplying by 3.07.
(that is most of the P in your sample was PO4, no huge surprises.)

Phosphate products like LoudWolf Sodium Phosphate or Trisodium Phosphate

Or….

Phosphorus products like Seachem Flourish.

Do these both dose “Phosphate” back to the system or is one dosing “phosphate” and the other dosing “phosphorus?”

To my knowledge, these are all products that dose PO4. The exact compounds in the product isn't really all that important. In the water, they all become (and test) as soluble reactive phosphorus, PO4.
Some products talk about the P content and some about PO4 content, but that's just different measurement units. Not a difference in what's provided.

 

[Reefahholic]

Nice. PO4 chemical test lines up close to the expectation by taking the P ICP test and multiplying by 3.07.
(that is most of the P in your sample was PO4, no huge surprises.)



To my knowledge, these are all products that dose PO4. The exact compounds in the product isn't really all that important. In the water, they all become (and test) as soluble reactive phosphorus, PO4.
Some products talk about the P content and some about PO4 content, but that's just different measurement units. Not a difference in what's provided.

So essentially if you’re dosing a phosphorus product like Brightwell Neophos or a phosphate product like LoudWolf TSP… They are both adding PO4 and neither one is any different than the other?

 

[Dennis Cartier]

So essentially if you’re dosing a phosphorus product like Brightwell Neophos or a phosphate product like LoudWolf TSP… They are both adding PO4 and neither one is any different than the other?

Correct. They are all adding phosphorus, usually in the form of phosphate. When you use a Hanna Checker, you are detecting the orthophosphate. The P in PO4, so to speak.

However, the Hanna checkers cannot detect organic phosphorus. For an example of this, see Tropic Marin's Plus NP product, which provides phosphorus in an organic form. They warn you that you will not be able to detect the phosphorus initially after addition. After a few days it will show up on your Hanna if it has not been used up before that.

 

[Randy Holmes-Farley]

I’m gonna be really ticked if I’ve been dosing Trisodium Phosphate and using the Hanna ULR phosphorus to try and detect it if it really cannot detect it. It’s somehow being working for years if that is the case.

I’m getting Zero’s on both Hanna Phosphate ULR and Phosphorus ULR…

Sooooo….

ICP below:

Analysis result

ATI Aquaristik - Lab

lab.atiaquaristik.com

Relax. All methods reefers use detect the phosphate in sodium phosphate.

Seachem Fluorish phosphorus is also identical to sodium phosphate in form:inorganic orthophosphate.

 

[Randy Holmes-Farley]

However, the Hanna checkers cannot detect inorganic phosphorus.

Typo.

 

[Dennis Cartier]

Typo.

Oops, thanks. Fixed

 

[Christoph]

Hello everybody!

A few hours offline, and im missing all the action in this thread ;-)

We do measure total phosphorus (via ICP-OES or ICP-MS, depending on which method the customer chooses) and also orthophosphate (PO4) using a photometric method based on the molybdenum blue/ascorbic acid method. We are using a Shimadzu Lab photometer with 4 cm optical path to have low detection limits. We do not calculate a phosphate value from the ICP data.

Phosphate is not very sensitive on ion chromatography (since it has a low specific conductivity), thus IC is not very useful for detection of phosphate in reef tanks. Photometry is the superior method in this case.

In case of higher phosphate levels total phosphorus and orthophosphate often agree very well - so most of the phosphorus in the sample is actually phosphate. This is not always the case, especially at lower nutrient levels, where a significant proportion of total phosphorus can be something else (might be oligophosphates or DNA or other phosphorus containing molecules).

We are using an orthophosphate based salt for phosphorus dosing, and i would be surprised if other products/brands would use other phosphorus sources. In my opinion it is important to dose phosphate spread out over several dposings per day, to achieve a constant availability. Otherwise this important nutrient might be depleted fast - either by consumption/metabolism, or by adsorption onto surfaces. Cycling between "available state" and "limitation" is imo stressful for corals, and should thus be avoided.


Best regards,
Christoph

 

[Woodyman]

Hello everybody!

A few hours offline, and im missing all the action in this thread ;-)

We do measure total phosphorus (via ICP-OES or ICP-MS, depending on which method the customer chooses) and also orthophosphate (PO4) using a photometric method based on the molybdenum blue/ascorbic acid method. We are using a Shimadzu Lab photometer with 4 cm optical path to have low detection limits. We do not calculate a phosphate value from the ICP data.

Phosphate is not very sensitive on ion chromatography (since it has a low specific conductivity), thus IC is not very useful for detection of phosphate in reef tanks. Photometry is the superior method in this case.

In case of higher phosphate levels total phosphorus and orthophosphate often agree very well - so most of the phosphorus in the sample is actually phosphate. This is not always the case, especially at lower nutrient levels, where a significant proportion of total phosphorus can be something else (might be oligophosphates or DNA or other phosphorus containing molecules).

We are using an orthophosphate based salt for phosphorus dosing, and i would be surprised if other products/brands would use other phosphorus sources. In my opinion it is important to dose phosphate spread out over several dposings per day, to achieve a constant availability. Otherwise this important nutrient might be depleted fast - either by consumption/metabolism, or by adsorption onto surfaces. Cycling between "available state" and "limitation" is imo stressful for corals, and should thus be avoided.


Best regards,
Christoph

Thanks for the info. I'll shoot you a PM. I'm in the middle of an ICP/IC equipment upgrade working with shimadzu now! So now I've got even more questions for you since your already using them!

 

[Reefahholic]

They warn you that you will not be able to detect the phosphorus initially after addition. After a few days it will show up on your Hanna if it has not been used up before that.

Which is the same as any phosphate product just in different form? What is the “benefit” of using an “organic” form over “inorganic?” Why is it not detectable initially, but becomes detectable later?

In my opinion it is important to dose phosphate spread out over several dposings per day, to achieve a constant availability. Otherwise this important nutrient might be depleted fast - either by consumption/metabolism, or by adsorption onto surfaces.

Yes sir! I’ve already got my GHL dosing 60 x 0.1 for a total of 6 mL and 0.06 ppm added daily. A dose is hitting the water about every 25 minutes or so. Last night I manually dosed 4 extra mL’s (0.04 ppm) on top of the auto dose schedule and I still cannot get readings on my Hanna phosphorus ULR! I would get a 1 (ppb) randomly, but then 1 Hr later it’s gone.

I have never had to dose so much PO4 back to any system. There must be A LOT of consumption, metabolism, absorption, etc…by everything in the tank right now.

I literally sat there last night staring at the tank thinking two things.

1. Either the tank is sucking it up like cool-aid and I’m very low or depleted hence the continuous zero readings on the Hanna Phosphorus ULR.

Or…

2. I’m way over dosing and the meter is not detecting it. However, I do not observe a lot of algae all over the glass. It’s the complete opposite. I can go at least 5-7 days without scraping anything off the glass.

So I studied all my data (I keep a lot of notes) and sat in deep thought. All the evidence is pointing to low/depleted PO4 level. My tank went to zero right when the ALK demand went up which is a common occurrence I see time and time again. This was also when I got my calcium reactor online. There are initial signs of Dino’s in the tank. The water will typically become cloudy when the PO4 drops very low or gets depleted and I always notice a weird brown and green film algae appear on the glass and on the rocks in spots. I notice the water will become the most cloudy during peak photo period and my theory for this is because the PO4 is being consumed/utilized the most during this time.

So all the evidence points to low/depleted PO4, but it’s hard to believe it because I’m dosing a lot. You would think I’d get a reading- especially in the early morning hours. I keep noticing when I manually dose 1 mL on top of my auto schedule that the water seems to clear up slightly shortly after these doses which is again another sign that the tank is low or depleted.