Oceamo Skimmate Analysis Results Discussion

Randy Holmes-Farley

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In a different thread, Christoph of Oceamo posted some analysis data for skimmate, and I'd like to start this thread for discussion of it. One thing I'm hoping Christoph can add is an analysis for the tank water that was on the same tank, so we can readily see how enriched or not the skimmate is with respect to various ions. here's the data he posted so far:

@Christoph


id like to post a typical example of a SkimQuant result, which is conducted by ICP-MS from a acid digested skimmate sample. When collection time and skimmate volume is also given, it is possible to calculate a daily export rate.

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Miami Reef

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One thing I'm hoping CHristoph can add is an analysis for the tnakw ater that wasd on the same tank
Can you clarify what you meant here? I’m having trouble understanding.
 
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Randy Holmes-Farley

Randy Holmes-Farley

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Can you clarify what you meant here? I’m having trouble understanding.

The data is for skimmate only. If the skimmate contains 20 ug/l iron (made up data), is that enriched relative to the tank water itself, or not? A skimmer that removed only exactly what is in the water is then identical to doing a tiny water change. It needs to be enriched (higher concentration in skimmate than the tank) to be significantly effective at removing something. Ron Shimek made that mistake in his early skimmate analysis article and what it accomplished. That required correction of the article.
 

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You need to know the source water values of the measured elements ,etc. so that "change/difference can be quantified. In other words "are we just exporting saltwater?" or are we exporting things at an elevated level. That is my understanding, please feel free to correct me.
 
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Randy Holmes-Farley

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You need to know the source water values of the measured elements ,etc. so that "change/difference can be quantified. In other words "are we just exporting saltwater?" or are we exporting things at an elevated level. That is my understanding, please feel free to correct me.

Yep. :)
 

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Pretty interesting! I can’t wait to see how this science develops. Besides skimmate, I’d also be interested to see how GAC exports metals over time. I wonder if that could also be tested with an acid extraction / digestion.
 
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Randy Holmes-Farley

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Pretty interesting! I can’t wait to see how this science develops. Besides skimmate, I’d also be interested to see how GAC exports metals over time. I wonder if that could also be tested with an acid extraction / digestion.

One concern would be ensuring that all elements are removed from the gac for testing without dissolving any of the gac itself and thus releasing elements internal to it. Such things could likely be overcome, or substracted out as a background, but perhaps not as readily as for skimmate.
 

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The data is for skimmate only. If the skimmate contains 20 ug/l iron (made up data), is that enriched relative to the tank water itself, or not? A skimmer that removed only exactly what is in the water is then identical to doing a tiny water change. It needs to be enriched (higher concentration in skimmate than the tank) to be significantly effective at removing something. Ron Shimek made that mistake in his early skimmate analysis article and what it accomplished. That required correction of the article.
Shouldn't the only enriched species in the water should be proteins and their chemical species?
The purpose of a protein skimmer is too remove proteins. I don't see where iron or TA or calcium, etc would be enriched in the skimmate. Most species listed are not even hydrophobic and so won't stick to the bubble surface.

I think that it is fairly evident with the color of the skimmate on how well the skimmer is working.
 
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Randy Holmes-Farley

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Shouldn't the only enriched species in the water should be proteins and their chemical species?
The purpose of a protein skimmer is too remove proteins. I don't see where iron or TA or calcium, etc would be enriched in the skimmate. Most species listed are not even hydrophobic and so won't stick to the bubble surface.

I think that it is fairly evident with the color of the skimmate on how well the skimmer is working.

Calcium binds to organics, but most notably, there is known to be calcium carbonate particulates in skimmate that will dissolve in the acid treatment, giving calcium a seeming false high reading. Same for other ions in that calcium carbonate, such as magnesium.

Most of the transition elements (iron, copper, etc.) will bind to organics which themselves bind to air/water interfaces, so they can be selectively removed by skimming even when the bare ions would not skim out.

Skimmate will also contain whole organisms such as bacteria and phytoplankton that may mostly dissolve into an acid treatment, releasing their contents for analysis, which needs to be considered at least when thinking about how ions such as phosphate or vanadium or many others show up.
 

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Pretty interesting! I can’t wait to see how this science develops. Besides skimmate, I’d also be interested to see how GAC exports metals over time. I wonder if that could also be tested with an acid extraction / digestion.
You may find this interesting.....https://en.oceamo.com/reaktormedien2/
 

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Wow that analysis is terrific and eye opening! I think I may cut back on GAC usage. Thanks a lot!

Please remember it represents but one data set and go easy. Like most of this hobby we are still learning what "studies" data actually mean to us. If your tank is happy then make only small changes.
 
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I'd be cautious in interpreting that data. The intent was, I'm sure, to readily see what was and was not bound, not how much in typical use. As I'm certain Christoph will attest, the amounts of media used were very large. For a 100 gallon aquarium, its akin to 10 gallons of media.

Then 10 bed volumes of sample solution (natural seawater, partly with element spikes) were slowly allowed to drip through the media bed.
 

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I'd be cautious in interpreting that data. The intent was, I'm sure, to readily see what was and was not bound, not how much in typical use. As I'm certain Christoph will attest, the amounts of media used were very large. For a 100 gallon aquarium, its akin to 10 gallons of media.

Then 10 bed volumes of sample solution (natural seawater, partly with element spikes) were slowly allowed to drip through the media bed.

Thanks for the context. I missed that point about the volumes. Albeit, their results do roughly track with what my ICP test showed. I’m using GAC and got very low iodine, undetected iron, good Mn, and undetected copper. The only reason for the GAC use was I don’t run a skimmer in my AIO. I thought water changes and GAC could replace the need for a skimmer. Anyways, I might reduce the media usage to see if the iodine comes up on the next ICP.
 

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Does anyone know if phosphate is being calculated from phosphorus or is that from water being removed?
 
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Randy Holmes-Farley

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Does anyone know if phosphate is being calculated from phosphorus or is that from water being removed?

Which study are you asking about? If it is the skimmate study, its from the ICP of the digested skimmate generated each day.
 

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The data is for skimmate only. If the skimmate contains 20 ug/l iron (made up data), is that enriched relative to the tank water itself, or not? A skimmer that removed only exactly what is in the water is then identical to doing a tiny water change. It needs to be enriched (higher concentration in skimmate than the tank) to be significantly effective at removing something. Ron Shimek made that mistake in his early skimmate analysis article and what it accomplished. That required correction of the article.
I think we will need the tank volume and skimmate volume also, because if you have a tiny volume of dry skimmate vs a large volume of wet skimmate with the same analysis, the enrichment numbers alone could be misleading. Also, I want to know how the concentration in the aquarium is changing from skimming. The increase in concentration in the skimmate is interesting but maybe not useful. For example, the iron and aluminum numbers are eye catching, but they could be a big “so what” if we find out these quantities only represent one billionth of the total amount in the aquarium. Hence, we need system and skimmate volumes for this analysis to be useful.
 
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Randy Holmes-Farley

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I think we will need the tank volume and skimmate volume also, because if you have a tiny volume of dry skimmate vs a large volume of wet skimmate with the same analysis, the enrichment numbers alone could be misleading. Also, I want to know how the concentration in the aquarium is changing from skimming. The increase in concentration in the skimmate is interesting but maybe not useful. For example, the iron and aluminum numbers are eye catching, but they could be a big “so what” if we find out these quantities only represent one billionth of the total amount in the aquarium. Hence, we need system and skimmate volumes for this analysis to be useful.

I expect (hope) that is what Christoph used to determine export in ug/L/day in the lower set of data. :)
 

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