ICP Test Results

[Rickyrooz]

Hello,
I had my water tested by ICP-Analysis.com on Monday and another sample 3 months ago was sent to Aquaforest. The minor trace element values vary greatly, should I take the new sample results with a grain of salt? I have been dosing Seachem Reef Trace as well as Seachem Reef Plus at one cap per week for each tank so there should be some amount of minor trace elements reading in the new test.


ICP-Analysis.com Results

Aquaforest Results
120 Gallon

160 Gallon

 

[Randy Holmes-Farley]

Trace elements are the hardest thing to get right by ICP of seawater, and I don't know much about the accuracy of their particular protocols, but they certainly might all be right, or not

I would say that the timing in relation to trace element dosing will make a huge difference.

Are there any particular values that concern you?

 

[Rickyrooz]

Trace elements are the hardest thing to get right by ICP of seawater, and I don't know much about the accuracy of their particular protocols, but they certainly might all be right, or not

I would say that the timing in relation to trace element dosing will make a huge difference.

Are there any particular values that concern you?

Nothing is too concerning with the results but I did expect my manganese and molybdenum levels to be above 0.00 ppm based on my dosing. Maybe these values are correct as I have noticed my chaeto does not grow much. The iron level was also 0.00 ppm. I am glad you mentioned timing of dosing when sampling the water because the 120 gallon that shows 0.01 ppm of iodide was dosed with lugol's a few hours prior to sampling. I do run BRS ROX 0.8 carbon, do you think the carbon could be absorbing the trace elements or do you believe to corals will uptake the majority of trace elements?

 

[drawman]

Yikes just looking at a few of the numbers it's crazy how much they differ. Calcium and Magnesium for one differ quite a bit. I ordered a test by ICP-analysis earlier this week. Unfortunately I won't have one to compare it to.

I would be curious what are you testing calcium and magnesium at in these tanks? Obviously you have to take it all with a big grain of salt.

 

[Randy Holmes-Farley]

Nothing is too concerning with the results but I did expect my manganese and molybdenum levels to be above 0.00 ppm based on my dosing. Maybe these values are correct as I have noticed my chaeto does not grow much. The iron level was also 0.00 ppm. I am glad you mentioned timing of dosing when sampling the water because the 120 gallon that shows 0.01 ppm of iodide was dosed with lugol's a few hours prior to sampling. I do run BRS ROX 0.8 carbon, do you think the carbon could be absorbing the trace elements or do you believe to corals will uptake the majority of trace elements?

Some trace elements should be (are) undetectable at NSW levels (e.g., iron, chromium, cobalt). So you need not always detect them to have enough.

Here's my commentary on my test results and how I interpret them:

My Triton Testing Results: By Randy Holmes-Farley
http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/

from it:

Iron (Fe). The natural iron level varies a lot with depth, but surface seawater may have only 0.006 µg/L. The Triton LOD = 0.3 µg/L. I dose iron, and when I dose it I boost iron to roughly 1-2 µg/L, which would be detectable. This sample was taken more than a week after the last iron dosing, and none was detected as it gets depleted in the meanwhile. I’ve not yet seen a Triton test result for a real aquarium sample that had detectable iron, but that doesn’t mean these tanks are necessarily deficient. Iron is also a case where the form is critical, and ICP cannot distinguish form. Binding to organic matter, for example, can alter the bioavailability of iron.

 

[Randy Holmes-Farley]

Yikes just looking at a few of the numbers it's crazy how much they differ. Calcium and Magnesium for one differ quite a bit. I ordered a test by ICP-analysis earlier this week. Unfortunately I won't have one to compare it to.

I would be curious what are you testing calcium and magnesium at in these tanks? Obviously you have to take it all with a big grain of salt.

Either his salinity is varying substantially, or one of them is not accurate. Sodium and S (sulfate) (2 of the 3 highest concentration ions by weight, and ones that do not vary day to day except by salinity changes) are lower in the first one.

 

[drawman]

Either his salinity is varying substantially, or one of them is not accurate. Sodium and S (sulfate) (2 of the 3 highest concentration ions by weight, and ones that do not vary day to day except by salinity changes) are lower in the first one.

I imagine that major ions can vary in concentration significantly from aquarium to aquarium at the same salinity. In your article you discussed that at normal salinity Na+Ca+Mg+K should equal around 12,900mg/L. Is there a range that would be within reason (ie your tank was at roughly 12,600mg/L) for 35ppt? Obviously this could be problematic for interpretation if you have an incorrectly calibrated refractometer...

 

[Randy Holmes-Farley]

How much variation is OK depends on how much you thing salinity can vary OK.

Luckily, most of our creatures are not very sensitive to the exact salinity (as long as it is stable).

So, say 34-36 ppt is fine. Wider range is probably fine too, but lets just loot at this.

At 34 ppt, that 12,900 mg/l becomes 12,531 (34/35 x 12,900) and at 36 ppt becomes 13,268.

The top set of data is 12,146. Probably close to 33 ppt.

That's probably fine, but if one wants to raise the values, raising the salinity is an easy way.

 

[drawman]

How much variation is OK depends on how much you thing salinity can vary OK.

Luckily, most of our creatures are not very sensitive to the exact salinity (as long as it is stable).

So, say 34-36 ppt is fine. Wider range is probably fine too, but lets just loot at this.

At 34 ppt, that 12,900 mg/l becomes 12,531 (34/35 x 12,900) and at 36 ppt becomes 13,268.

The top set of data is 12,146. Probably close to 33 ppt.

That's probably fine, but if one wants to raise the values, raising the salinity is an easy way.

I guess I was considering this as a "standard" of sorts to determine how the accurate the other values would be. Say if you are relatively confident (take this with a huge grain of salt) that your salinity is 35ppt and the total of Na+Ca+Mg+K is way off from that 12,900mg/L value then you know something is off. However, with refractometer calibration, etc. this idea of using this as a standard seems to break down very quickly imo. Just thinking out loud I guess

On the flip side you could probably be able to tell that your refractometer is calibrated incorrectly using this (but again would need to take that with a grain of salt I'm sure).

Do these machines need to be recalibrated often Randy? I wonder how likely these companies are to keep them well maintained.

Sorry I am hijacking this thread way too much...

 

[Randy Holmes-Farley]

Do these machines need to be recalibrated often Randy? I wonder how likely these companies are to keep them well maintained.
.

These machines may need a standard, such as a standard curve with values above and below those tested, run frequently (like every day). That's what analytical chemists do, and what I did when I used one for reef samples of various sorts. I have no idea what calibration methods they have used, however.

 

[Rickyrooz]

Yikes just looking at a few of the numbers it's crazy how much they differ. Calcium and Magnesium for one differ quite a bit. I ordered a test by ICP-analysis earlier this week. Unfortunately I won't have one to compare it to.

I would be curious what are you testing calcium and magnesium at in these tanks? Obviously you have to take it all with a big grain of salt.

The two tests were taken months apart. I was using the Aquaforest results to compare to the new ICP-Analysis.com test as none of the minor trace elements registered on the new test compared to the Aquaforest results. I use Salifert to test alkalinity, calcium and magnesium. Alkalinity stays between 7.5-8 dKH, calcium fluctuates between 420-430 and magnesium is 1350-1370. I keep my salinity around 34ppt, I prefer to use Aqua Craft refractometer solution as it drips from an eye dropper and have less evaporation than the Pinpoint solution.