Skimmer shows little difference in N-DOC organic parameters

[Chris Villalobos]

Randy,

I know this is just anecdotal evidence but I'm pretty disappointed in the results of adding an expensive skimmer to my small reef tank. I had not changed my feeding pattern significantly in the duration of the testing period.

Looking at TOC and TNb (minus NO3 tested). I cannot find a significant decline in organics in my system. Are skimmers overrated?

Here are my results with skimmer off. Notice that my tested NO3 is 5ppm.
TOC: 4.01mg/l
Nitrogen is a little more diffulcult to figure out since the first test had 5PPM NO3 due to the NaNO3 dosing I was doing at the time. If we take N/N03 calcuated and subtract NO3 of 5 we get: 6.76 mg/l

Skimmer on for a month:
TOC: 4.45mg/l
N/NO3 minus tested NO3 of o.25 = 6.56 mg/l



SKIMMER OFF

SKIMMER ON for a Month.

 

[elisa h]

Interesting! I don’t personally use a skimmer anymore and see no negative effects whatsoever. Nobody seems to know what exactly they are pulling out of the water. And how much of that stuff is actually something that should be removed from the system? I wonder if triton could do a test on some skimmate. I personally pulled mine off because my house is very full of people and dogs (so high co2) so it was driving my ph down

 

[zoous]

Do you do water changes every week? Honestly I use to run my tank skimmer less and had no issues.

 

[Chris Villalobos]

Do you do water changes every week? Honestly I use to run my tank skimmer less and had no issues.

I did one water 20% change during the month. Triton is supposed to be a zero water change system though I may end up returning to a regular water change schedule due to contaminants that tend to build up in my system over time.

 

[Dan_P]

Randy,

I know this is just anecdotal evidence but I'm pretty disappointed in the results of adding an expensive skimmer to my small reef tank. I had not changed my feeding pattern significantly in the duration of the testing period.

Looking at TOC and TNb (minus NO3 tested). I cannot find a significant decline in organics in my system. Are skimmers overrated?

Here are my results with skimmer off. Notice that my tested NO3 is 5ppm.
TOC: 4.01mg/l
Nitrogen is a little more diffulcult to figure out since the first test had 5PPM NO3 due to the NaNO3 dosing I was doing at the time. If we take N/N03 calcuated and subtract NO3 of 5 we get: 6.76 mg/l

Skimmer on for a month:
TOC: 4.45mg/l
N/NO3 minus tested NO3 of o.25 = 6.56 mg/l



SKIMMER OFF

SKIMMER ON for a Month.

How do run your skimmer wet or dry? How many ounces or milliters of skimmate are you removing per day?

 

[Chris Villalobos]

How do run your skimmer wet or dry? How many ounces or milliters of skimmate are you removing per day?

Good question, I had the skimmer set up to remove around 25ml per day for my 32 gallon display + 20 gallon sump. I've had two different types of skimmers a Bubble Magus and a Tunze 9004. Both have given me a green watery skimmate and never the black stuff some people pull out of their skim cups.

I've read some studies of skimmers and at best they pull out only 20% to 30% of TOC. I wonder how many people are just blowing money on these things.

https://webcache.googleusercontent....m/2009/1/aafeature2+&cd=4&hl=en&ct=clnk&gl=us

 

[Randy Holmes-Farley Verified Community Expert]

Interesting! I don’t personally use a skimmer anymore and see no negative effects whatsoever. Nobody seems to know what exactly they are pulling out of the water. And how much of that stuff is actually something that should be removed from the system? I wonder if triton could do a test on some skimmate. I personally pulled mine off because my house is very full of people and dogs (so high co2) so it was driving my ph down

There have been extensive analyses of the elemental composition of skimmate. Ron Shimek did some years ago.

 

[Randy Holmes-Farley Verified Community Expert]

Randy,

I know this is just anecdotal evidence but I'm pretty disappointed in the results of adding an expensive skimmer to my small reef tank. I had not changed my feeding pattern significantly in the duration of the testing period.

Looking at TOC and TNb (minus NO3 tested). I cannot find a significant decline in organics in my system. Are skimmers overrated?

Here are my results with skimmer off. Notice that my tested NO3 is 5ppm.
TOC: 4.01mg/l
Nitrogen is a little more diffulcult to figure out since the first test had 5PPM NO3 due to the NaNO3 dosing I was doing at the time. If we take N/N03 calcuated and subtract NO3 of 5 we get: 6.76 mg/l

Skimmer on for a month:
TOC: 4.45mg/l
N/NO3 minus tested NO3 of o.25 = 6.56 mg/l



SKIMMER OFF

SKIMMER ON for a Month.

I would run a skimmer just for aeration.

There are numerous organics that cannot be skimmed and others that can be. A skimmed system may just preferentially accumulate those that cannot be.

Is the organic removal beneficial? That’s more complicated to answer and may depend on the system. Try turning it off and see what happens visually to organisms.

 

[Dan_P]

Good question, I had the skimmer set up to remove around 25ml per day for my 32 gallon display + 20 gallon sump. I've had two different types of skimmers a Bubble Magus and a Tunze 9004. Both have given me a green watery skimmate and never the black stuff some people pull out of their skim cups.

I've read some studies of skimmers and at best they pull out only 20% to 30% of TOC. I wonder how many people are just blowing money on these things.

https://webcache.googleusercontent....m/2009/1/aafeature2+&cd=4&hl=en&ct=clnk&gl=us

As a starting point of discussion, if the skimmate volume collected per day is about 1% of the system’s volume and you are not happy with the reduction in the amount of dissolved organic carbon and nitrogen in your system after adding the skimmer, you have a case against your skimmer. But rare is the aquarist that measures DOC and DON before and after adding a skimmer AND runs the skimmer near peak efficiency.

I like your question about expense vs benefit and I have read the articles you mentioned. I have the impression that no one has provided data showing the benefit of removing the organic chemicals in the water. No good experimental results providing a solid link between removing “XYZ” and reducing some aquarium malady. I think it is also safe to say that most aquarists think that running the skimmer relatively dry to accumulate gunk in the collection cup is the goal. I have made measurements that show (which need additional verification before I share them) that running a skimmer such that it collects gunk instead of, say, a lot of beer colored foamate may not be running the skimmer most efficiently.

As Randy has pointed out, if you use the skimmer throat to concentrate DOC, some will return to the system. In other words, choosing to concentrate DOC results in a DOC traffic jam. Less material is leaving the system per minute because it is churning in the throat concentrating, not flowing out of the system.

The cost of quickly removing DOC from the system, that is, capturing DOC on a bubble and letting it pretty much rise through the throat and out as wet foam is the loss of aquarium water. The benefit is that removing DOC faster might more closely match its production rate and minimize DOC accumulation.

But does it matter that you operate the skimmer more efficiently? I don’t know. I do like the notion of doing the best I can to remove as much waste as I can, but that might just be a reflection of my childhood training But that is all. No claims about reducing algae, diatoms, dinoflagellates, or cyanobacteria.

So, you did not see a difference in the chemical analysis, possibly, because of the way the skimmer is being run, not necessarily that the skimmer isn’t working. And as was pointed out, the skimmer cannot remove all the DOC anyway.

 

[Dan_P]

Randy,

I know this is just anecdotal evidence but I'm pretty disappointed in the results of adding an expensive skimmer to my small reef tank. I had not changed my feeding pattern significantly in the duration of the testing period.

Looking at TOC and TNb (minus NO3 tested). I cannot find a significant decline in organics in my system. Are skimmers overrated?

Here are my results with skimmer off. Notice that my tested NO3 is 5ppm.
TOC: 4.01mg/l
Nitrogen is a little more diffulcult to figure out since the first test had 5PPM NO3 due to the NaNO3 dosing I was doing at the time. If we take N/N03 calcuated and subtract NO3 of 5 we get: 6.76 mg/l

Skimmer on for a month:
TOC: 4.45mg/l
N/NO3 minus tested NO3 of o.25 = 6.56 mg/l



SKIMMER OFF

SKIMMER ON for a Month.

Would explain the nitrogen result again? Does the Triton result for N mean total nitrogen measured? And do you then subtract the measured nitrate nitrogen from the total? I am lost. Thanks

 

[Dkeller_nc]

One observation is that your TOC analysis suggests that your aquarium water is already very low in total organic carbon in the first place. You have 4 ppm of TOC, and a round figure for the expected TOC in treated drinking water is about 2-4 ppm. Note that's treated water, that's typically gone through an activated carbon bed. Surface waters around the coasts of the world can be much higher, including on coral reefs. Even on pristine reefs, and with all particulate carbon filtered out (it's unclear to me whether Triton filters samples), somewhere between 1 - 10 ppm TOC is noted in the studies I've read in the past.

And the concentration of surface-active molecules must actually be above a certain concentration for a stable foam to develop and anything to be skimmed out (this is called the Critical Micelle Concentration, or CMC, btw).

In other words, you may simply not have enough TOC in your system to actually skim much out in the first place. Having said that, what you've captured are snapshots; it's a pretty good bet that your skimmer is removing quite a bit for the first hour or two after your fish have been fed or you've added coral foods.

Edit: By the way, please ignore Triton's idiotic "warning lamp" values for something like TOC. They have no idea what is/is not healthy for a reef tank, and neither does anyone else. It just hasn't been studied.

 

[Chris Villalobos]

Would explain the nitrogen result again? Does the Triton result for N mean total nitrogen measured? And do you then subtract the measured nitrate nitrogen from the total? I am lost. Thanks

For some reason Nitrogen is unstable and needs to be tested by the aquarist to get the most accurate reading of organics. I'm guessing that the bacteria in the sample are still breaking the forms of Nitrogen down to NO3 while in transit.

 

[Dan_P]

For some reason Nitrogen is unstable and needs to be tested by the aquarist to get the most accurate reading of organics. I'm guessing that the bacteria in the sample are still breaking the forms of Nitrogen down to NO3 while in transit.

So, the number Triton sends you is total nitrogen. The customer measures the nitrate content and subtracts the nitrate nitrogen from the total nitrogen. The remainder is an estimate of organic nitrogen, correct?

 

[Chris Villalobos]

I was hoping that running a skimmer would reduce the organic Nitrogen in my tank since I've been having issues with Dinos and Cyano and I have a theory that both of those issues are being caused by the amount of organics in my tank. I'm disappointed that the skimmer wasn't able to have any impact. Could I have run it wetter? Maybe. I've currently stopped running it, lowered my feedings, and reduced the lighting on my chaeto. I'm still having to dose NO3 and PO4. I was able beat the Dinos but the Cyano is proving harder to eradicate.

I think the N-DOC is an interesting tool and hopefully more people will perform simaliar tests on their own tanks.

 

[Chris Villalobos]

So, the number Triton sends you is total nitrogen. The customer measures the nitrate content and subtracts the nitrate nitrogen from the total nitrogen. The remainder is an estimate of organic nitrogen, correct?

Yes. They also recommend that the aquarist test for NH3 and NO2.

 

[Dan_P]

I was hoping that running a skimmer would reduce the organic Nitrogen in my tank since I've been having issues with Dinos and Cyano and I have a theory that both of those issues are being caused by the amount of organics in my tank. I'm disappointed that the skimmer wasn't able to have any impact. Could I have run it wetter? Maybe. I've currently stopped running it, lowered my feedings, and reduced the lighting on my chaeto. I'm still having to dose NO3 and PO4. I was able beat the Dinos but the Cyano is proving harder to eradicate.

I think the N-DOC is an interesting tool and hopefully more people will perform simaliar tests on their own tanks.

I appreciate what you are saying. I will be using N-DOC to correlate two simple chemical methods I am developing to measure dissolved organic carbon. I can’t afford the number of TRITON tests to address questions like yours. If all goes well, my tactics will be to use the cheap chemical methods for research and an occassional sanity test with an N-DOC test.

 

[Chris Villalobos]

I appreciate what you are saying. I will be using N-DOC to correlate two simple chemical methods I am developing to measure dissolved organic carbon. I can’t afford the number of TRITON tests to address questions like yours. If all goes well, my tactics will be to use the cheap chemical methods for research and an occassional sanity test with an N-DOC test.

If you can develop a simple organic carbon test I'm sure every carbon doser will be beating a path to your door.

 

[Dan_P]

If you can develop a simple organic carbon test I'm sure every carbon doser will be beating a path to your door.

Thanks for the enthusiasm!

But alas, neither a simple method nor TRITON N-DOC will help much in determining the concentration of organic carbon being dosed. The simple methods will unlikely detect acetate and may not notice ethanol. N-DOC will not likely help either because dosed ethanol and/or vinegar are consumed quickly, gone by the time it reaches their lab. Also, because the time the sample is in transit varies and the sample temperature is not controlled, two identical samples containing ethanol or vinegar will not give the same results.

The organic carbon TRITON is measuring is the stable stuff few organisms readily consume. The concentration of this less reactive carbon might be lowered as a result of dosing, assuming the bacteria don’t produce just as much unreactive waste.