What's in that skim mate?

[Gregcoyote]

Really good analysis;

Feature Article: Elemental Analysis of Skimmate: What Does a Protein Skimmer Actually Remove from Aquarium Water? — Advanced Aquarist | Aquarist Magazine and Blog


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[Sniperhank]

Pulled up an old gem there. Good stuff.

[Gregcoyote]

I thought it was fascinating what skimmers actually pull out of the water. Not as efficient as I always thought.


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[mr_X]

I wonder what the results would be on a different system. I mean, could there be any reason at all it might pull out more dissolved organic compounds on one system, than another?
I find this hard to believe, since the amount of skimmate pulled from my system is quite massive, and yet, I don't believe I add that much to the tank with just water changes and alk dosing.

[Gregcoyote]

It was interesting that a high percentage of the material was inorganic. Calcium and Mg being part of the total. It's only getting 30-35% of the dissolved organic carbon.

Funny they didn't address efficiency. Good point, I wonder if other skimmers are more effective on DOCs.

They addressed that it would be different between types of systems.


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[Sniperhank]

Should bottle up out skim and send it their way.


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[Gregcoyote]

I suspect the chemical analysis would cost significant $$.

I have considered shipping water out and getting a mass spectrograph of it. It would be nice to have a lab calibrate where I really am.


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[nelix10]

Just wondering why you are interested in mass spec analysis on your water? At work we get water isotope analysis done for about $150, this is in Canada! Water analysis can have a very wide range of price based on what you want to look at!


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[Sniperhank]

To know exactly what is going on in your tank. There is a ton of stuff going on in our water that even on a hobby grade we don't understand...and probably some on a higher level that we don't.
Consider those that claim some of the necessity of vitamin C and other such things for keeping coral... how is anyone to know for sure? Won't until someone dives into it.

[nelix10]

I hadn't read the the article before I commented what you are looking for is a elemental analyzer. It vaporizes the sample blasting apart the compounds. Very cool machine! Most universities have at least one of these, they can do many runs a day so are sometimes pretty cheap analysis!


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[PB_Smith]

Interesting, but far from conclusive science.
There are a couple of key factors not mentioned that greatly influence the composition of the skimmate being produced;
1) is the water being pulled directly from the tank or from a sump after going through a sock or other means of mechanical filtration?
2) what is the bubble/water contact time?


if pulling directly from the tank you will get much, much more organic matter in the skimmate than if pulling from the sump post filter sock.


contact time is probably the most crucial factor with overall bubble surface area being second.
Some compounds can take almost 2 minutes to be pulled out of solution. The longer the bubbles stay in the water/reaction chamber, the more compounds that can be removed.
Recirculating protein skimmers of the type used in the experiment do not achieve those contact times and attempt to make up for it by recirculating the water through the skimmer, but it's not the same as a prolonged contact time for each bubble.


I would love to see more thorough research utilizing different skimmer types and see what different results may be had between a recirculating skimmer and a tall counter-current type

[Gregcoyote]

Originally Posted by nelix10

Just wondering why you are interested in mass spec analysis on your water? At work we get water isotope analysis done for about $150, this is in Canada! Water analysis can have a very wide range of price based on what you want to look at!


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As I can only test for a half dozen simple chemicals, I would find it useful to compare my tank water to a average seawater sample from a reef. I know it will vary, but I would still be interested in if there were key elements raised or lower than normal.


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[Gregcoyote]

Originally Posted by PB_Smith

Interesting, but far from conclusive science.
There are a couple of key factors not mentioned that greatly influence the composition of the skimmate being produced;
1) is the water being pulled directly from the tank or from a sump after going through a sock or other means of mechanical filtration?
2) what is the bubble/water contact time?


if pulling directly from the tank you will get much, much more organic matter in the skimmate than if pulling from the sump post filter sock.


contact time is probably the most crucial factor with overall bubble surface area being second.
Some compounds can take almost 2 minutes to be pulled out of solution. The longer the bubbles stay in the water/reaction chamber, the more compounds that can be removed.
Recirculating protein skimmers of the type used in the experiment do not achieve those contact times and attempt to make up for it by recirculating the water through the skimmer, but it's not the same as a prolonged contact time for each bubble.


I would love to see more thorough research utilizing different skimmer types and see what different results may be had between a recirculating skimmer and a tall counter-current type

I agree. A independent test should be done with as many skimmers as available. Setting up a test bed would be fairly simple. Instead of using the output of a actual fish tank, you could selectively add elements to a test tank and see the efficiency of lifting those materials out of a defined volume of water.



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