New Skimmer – Price is no Object!

<a href=showthread.php?s=&postid=10643796#post10643796 target=_blank>Originally posted</a> by manderx
no. the real magic in countercurrent exchange is not about dwell time, but about maximizing the gradient (and therefore in theory total transfer) between the water/bubbles for as much of the dwell time as possible. i strongly suggest you read up on it. i would not consider any of the recirculating skimmers that i know of as countercurrent, even though they do feed input water near the top and exit the bottom, just too much mixing and turbulence within.
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Manderx,

Thanks very much for educating us about countercurrent skimmer principles. What skimmers are available that you think will maximize the gradient and organic transfer? My system is small (75-gallon) and my objective is “deeper skimming” to maximize water purity. While removing Gelbstoff will be nice, I will be satisfied if it can reduce the concentrations of the more soluble DOC’s that many skimmer designers have ceded to carbon filters.

By the way, do these freshwater skimmers employ countercurrent designs: http://www.schuran.com/freshwater/abschaeumer_e.html?

Freshwater skimmer designers have the same objective. They are trying to remove DOC's that are more soluble than the ordinary particulates and surface proteins. In freshwater, all DOC's are more soluble and harder to skim. Perhaps if we adopt some of their innovations, we may be able to skim Gelbstoff from saltwater aquariums in the future.
 
<a href=showthread.php?s=&postid=10645752#post10645752 target=_blank>Originally posted</a> by BeanAnimal
All of the skimmers would be sucking in the exact same mixture of water. That is the whole premise behind using the natural sea water :) It takes one variable out of the problem.
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Yeah, I understood that. But what I don't like about it is that a year later when the newest state of the art skimmer hits the market, there is no way to compare it to previously acquired data. That's why I would prefer a standardized ASW mix with a standardized concentration of a known organic compound. The test would certainly be more restrictive than using NSW but it would help to standardize things better across time. Otherswise, you only get one realistic shot to make comparisons.
FB
 
<a href=showthread.php?s=&postid=10643796#post10643796 target=_blank>Originally posted</a> by manderx
no. the real magic in countercurrent exchange is not about dwell time, but about maximizing the gradient (and therefore in theory total transfer) between the water/bubbles for as much of the dwell time as possible. i strongly suggest you read up on it. i would not consider any of the recirculating skimmers that i know of as countercurrent, even though they do feed input water near the top and exit the bottom, just too much mixing and turbulence within.

wiki came up first on google. if nothing else look at the pic.
http://en.wikipedia.org/wiki/Countercurrent_exchange



is there a new organics test from salifert? i got that one last year or so and it was absolutely worthless. the 'scale' was something like this:

"if it's clear you probably don't have an organics problem
if it's slightly yellow you might have an organics problem
if it's yellow you probably have an organics problem"

making any comparisons other than night&day would need a colorimeter of some sort. i dunno if you could use a hanna po4 meter for unscaled comparisons since it reads blue and this is yellow, but it might be worth a try.
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I agree... sorta. Most recirc skimmers dont use the counter current method as well as they could like you said, but counter current, if set up right, like on the Turboflotor 5000 series single and twin models, results in a longer dwell time because the bubbles arent just rising at their normal rate... they are being sucked down by the 1000gph of water being forced down that 8" diameter, 5' tall column of water. Still, even the shortest ER/deltec/H&S recirc skimmer is still introducing the water at the top, which is waaay better than just having it come in at the bottom and go right out the bottom outlet. So while it may not be the 'textbook' application of a countercurrent, its still much better than a single-pass in many respects.

Lol, that Salifert Organics test I have is worthless as well. I think Escobal and others actually had to sort out the various proteins collected in skimmate in a lab. Thats more than what most of us can do... except thorium maybe... hmmmm... I have to talk with the WRS secretary and see if he can test for various proteins in his lab. He does enzyme research, so proteins arent that far off.
 
Fishbulb:

Understood... and honestly I did not consider that. I guess that should have been obvious and it went right over my head.
 
As far as testing.... if a bunch of skimmers were lined up side by side in a sump, and run at the same time period... then their collection cup contents removed and condensed in an oven... couldnt you just weigh the results to see which comes out on top?

As far as 'yellowing compounds'... I think Bean had the idea that was still the best. Use a spectrometer (hey, I have one of those!) to measure the clarity of the system of what each skimmer leaves in the water. The problem is that you have to have so many equal amounts of water to skim at the same time.

The only problem I see with Fishbulb2's idea is that with ASW mix, and some compound... how similar to a real reef system are we getting then? As in... how do we know whatever compound we are adding is going to respond similar to an actual reef? An artificial additive may have proteins A, B, D, and P and the real reef may have A, B, E, and G for example... and one skimmer might be better with E while another may be better with D.

Also, beyond the variables of whats in the water, whats in the air can throw off things as well... so I dont think there is any way that the test could be replicated again later on anyways because you cant control the variables unless you redo the old results again. This wouldnt be too bad though... as long as you had one or two skimmers from the previous tests as a 'benchmark', you could compare based on that.

As for freshwater skimmers, they are done in the counter-current manner...
http://www.zinn-aquarientechnik.de/zc-englisch/sussw_-abschaumer.html

I dont know, but to me, that says something since freshwater is harder to skim or make stable bubbles with. So some of your best saltwater skimmers by comparison... or the ones most capable of removing the most variety of surfactants, would be tall and counter-current IMO.
 
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As far as testing.... if a bunch of skimmers were lined up side by side in a sump, and run at the same time period... then their collection cup contents removed and condensed in an oven... couldnt you just weigh the results to see which comes out on top?
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 They would be competing against one another and would nullify the test results. What would skimmer A have done of skimmer B was not working along side it?

Air could be easily controlled with filtration and a dryer. If you wanted to you could also control the atmoshpheric pressure etc.

The question still becomes who would bother and why? As a skimmer manufacturer I would not want to perform a test that is that complicated and can not be easily reproduced to change results with modifications.
 
True, they would be competing... and the results would be different perhaps if they werent... but so what. Its a competition anyways, right? We arent trying to determine which would perform better anyways, not what results one can expect on their own reef... thats impossible. I am also talking about a huuuuge source of water.... so 1000-2000 gallons so that the levels of skimmate wouldnt dive as the test goes on. At that NSW might just be the best source.

As for air, Im more concerned about oxygen content. You should see the pH shoot up in my tank when I draw air from outside rather than in the house. Many people's homes, esp their basements, have low oxygen levels. Temperature and humidity as well... I dont know that a dryer would be able to do all that. Just saying... I dont see any way to replicate everything in the environment at a later date... so all skimmers should be tested side by side at once, and if anything, a 'benchmark' skimmer could be used in future tests.

But yeah, I agree... who would bother, and why. Not to mention, would the results mean much to anyone. I just run carbon to remove the yellowing compounds at least. And I would say that whatever skimmer is best for your reef really depends on your reef and your habits. Do you remove detritus regularly? Do you run BB, 1" sand, or DSB? How many fish? What type of fish? Do you feed regularly, and what do you feed? Do you run a fuge? Do you have softies, SPS, clams, etc? On my new tank, my skimmate production is very very low... even with the tangs. It might jump up in the future as the fish grow, and as I finish stocking with fairy wrasses and my watanabei's, but right now, I dont care what skimmer I run... not alot is coming out. A DAS EX-1 is prolly all I need on it, even at 125g. Feeding the air from the outside, or maybe adding some ozone is all I should ever need.
 
I still think you want to avoid doing the test in an aquarium. Any standardized test should be able to be replicated by anyone. For example, it's nice that we can have multiple people in different places testing flow rates for modified pumps and all come out with a quantifiable number to assign each pump. Then we can measure their variability and compare future pumps to past pumps etc. The same goes with lighting. We can compare PAR and intensity for different bulbs all around the world and then compare our results. By using non-standardized solutions like an aquarium, it's just too uncontrolled. It means that all skimmers need to be compared at once and all testing would need to be done at one location by one individual. It's not attractive. I understand though why some don't like the idea of just using one compound to test skimming ability. But is a skimmers ability to extract compound A not directly proportional to it's ability to extract compound G? I would have guessed they would be since it's mainly based on hydrophobicity and a skimmers ability to combine as much air and water. But this is way out of my area of expertise so someone else will have to chime in if this assumption is wrong. I also really like Bean's idea of using a spectrometer to measure discoloration. I would use a simple phenol (which I think can tint the water yellow) and then measure with a spectrometer how well the skimmers can remove this compound. And then "assume" based on this that the skimmer will remove other compounds proportionally to this phenol.

All in all though, you guys are right. No one is going to bother setting up standardized skimmer testing because it would probably hurt many more manufactures than it would actually help. Heck, MH bulb manufactures don't even make available PAR readings for their bulbs. And that should be pretty trivial right?
 
Lowest Concentration

Lowest Concentration

Excellent points!

For my needs, I would not line up skimmers on the same sump and weight their collection cup contents. I would place skimmers on separate small tanks with water from the same source. The idea is to find out which skimmer achieves the lowest DOC concentration, not which skimmer is the fastest. Even if you do not have a “standard seawater solution,” you can compare two skimmers by using water from the same source (a water change from the same aquarium, perhaps?).

It is possible that ORP meters or colorimeters can be used for such comparison testing. If skimmers can skim Gelbstoff, you can probably stick raw aquarium water into a Hanna colorimeter with a blue LED and check the light absorption to indicate skimmer performance. Given the right wavelength (infrared, UV, etc.), we can probably perform such a quick colorimeter test to determine the level of other classes of DOC’s. Perhaps a chemical reagent may be needed to “bring out the color.” ORP meters can also be used for comparison testing between two skimmers when water is used from the same source.

Even without “standard seawater,” it may be possible to rank skimmers based on how low they can bring the concentration of a specific DOC. Skimmers remove insoluble compounds more readily than soluble ones. You will probably not find a skimmer that filters X better than Y and another skimmer that filters Y better than X. Starting with equal concentrations, both skimmers will remove the less soluble compound more readily. A good test will be to choose a DOC that is moderately hard to skim and see which skimmer reduces the concentration of that DOC the lowest. If skimmer-1 can reduce a DOC to level-1 and skimmer-2 can reduce the same DOC to level-2, then these tests may be repeatable and enable us to rank the skimmers.
 
Hahn, I would disagree that peoples homes have low oxygen levels. They may have higher CO2 levels, even some Radon... but 02 levels stay pretty even.

The change in atmoshperic pressure and CO2 levels have a lot to do with skimmer performance. The air inside and outside is also not always the same density due to vapor content.

I am not saying that oxygen levels indoors can not fluctuate, but they are pretty darn stable. I would attribut your observation to what I mentioned above more than I would oxygen.

FWIW I have spent a lot of my life carrying around gas monitors (O2, CO, CH4)... Remember I spent 16 years in the mining industry :)

20.9% or whatever oxygen content is standard for you altitude is a rather stable thing.

19.5% and below is considered "oxygen deficient" and 22% and above is considered "oxygen enriched"

I have worked in deadly low oxygen levels where you begin to have problems and in "black damp" where 1 breath will kill you.

There are three basic reasons that our standard oxygen levels would change in a confined space.

1) Respiration using up oxygen and replacing it with CO2
2) The oxidization of organics and metals (rotting wood, rusting metal, etc)
3) Displacement of oxygen by another gas.

In a home, the only applicable item is #1. In a coal mine, #2 and #3 are very real problems. Combine low air movement with exposed organics (coal, wood, iron) and you have a problem. Push a bunch of methane into that and things get even worse.
 
PJF is at all worth the trouble?

I think is the basic question. Of course different things interest different people...

I would stick with the best skimmer you can afford. I would base my choice on observation and anecdote. I would buy a bulk package of carbon that is know to not introduce phosphates and be done with it. Then again a lot of people don't agree with what I have to say so...
 
Inefficient Skimmer Market

Inefficient Skimmer Market

A casual glance at this forum will show skimmer threads repeating the same question: what is the best skimmer for my system? Yet, the wrong answer is invariably given. The skimmer buyer is given anecdotal evidence and told to look at the thick foam and the dark skimmate to determine the best skimmer. The manufacturers tout their skimmate, their foam, and their pumps but hide the cesspools that their skimmers are tested on. This is an endless cycle with each conscientious aquarist spending thousands for mediocre products with no progress in sight.

The correct answer is to look at the water column. The skimmers that deliver the highest water purity and the lowest DOC levels should be the ones that prevail in the marketplace. Yet the information that allows the buyer to make the wisest choices is not there. Therefore the aquarist assumes that the best skimmers are also the most expensive ones and spends accordingly.

We must break that cycle.

Consumers must demand benefits where they are needed â€"œ in the aquarium, not in the collection cup. Test kits should be cheaper, quicker, more accurate, and more focused on DOC’s. Manufacturers should focus on skimmers that produce the best water quality and be held accountable by the marketplace for their claims.

This requires a marketplace with informed consumers and that information must become available for there to be progress.
 
I would submit that the market is not big enough to build and implement a standard, let alone test against it :)

As mentioned, even if the skimmer manufacturers were skimming right out of the sewage treatment plant to get their sales collateral... they are not going to sign on to any kind of testing.

Look at audio power amplifiers. We have tried for 50 years to get the manufacturers to sign onto a standard for rating their power output. We have

Power at 1W 1M (1 watt 1 meter)
RMS watts
Peak watts
Etc

We then have the question as to what frequency range they were tested under and how to compare them to each other. Nobody plays along... they all skew their numbers to fit their marketing.


I would also submit, that if you see it in the collection cup, it is not in the tank. Therefore the darker and stinkier the collection cup, and the faster it gets that way, the better the skimmer :)
 
"Therefore the darker and stinkier the collection cup, and the faster it gets that way, the better the skimmer "

exactly. if you can pour the stuff in your skimmate cup back to your tank then you have a lousy skimmer. if you don't dare pour it back in then you're good to go. that's how i see it.

why are you so set on removing the yellowing compounds and that other stuff you speak of? if a skimmer is able to remove all matter indiscriminately at such a high efficiency rate then you will be removing all trace elements and beneficial crap just as well from your water column. there is no skimmer in the world that will discriminate in removing particles and matters from our systems, that is the bottom line.
 
<a href=showthread.php?s=&postid=10647987#post10647987 target=_blank>Originally posted</a> by ezcompany
there is no skimmer in the world that will discriminate in removing particles and matters from our systems, that is the bottom line.
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well actually I think the opposite is true. All skimmers discriminate based on how hydrophobic the DOC is. And trace elements tend to exist in our systems as charged ions. So it's not unreasonable to have a skimmer that clears a tank of DOCs and leaves trace elements like Ca ang Mg alone.
 
<a href=showthread.php?s=&postid=10647801#post10647801 target=_blank>Originally posted</a> by BeanAnimal
I would submit that the market is not big enough to build and implement a standard, let alone test against it :)

As mentioned, even if the skimmer manufacturers were skimming right out of the sewage treatment plant to get their sales collateral... they are not going to sign on to any kind of testing.

Look at audio power amplifiers. We have tried for 50 years to get the manufacturers to sign onto a standard for rating their power output. We have

Power at 1W 1M (1 watt 1 meter)
RMS watts
Peak watts
Etc

We then have the question as to what frequency range they were tested under and how to compare them to each other. Nobody plays along... they all skew their numbers to fit their marketing.


I would also submit, that if you see it in the collection cup, it is not in the tank. Therefore the darker and stinkier the collection cup, and the faster it gets that way, the better the skimmer :)
Click to expand...
We don't have to listen to the manufacturer's numbers if we have our own. The tests may be crude at the beginning (organic dyes, ORP, Salifert Organics, spectrophotometer, etc.) but they will improve with time. At the beginning, we will not even need a standard NSW. We can use the same water source for one-on-one comparisons.

Richard Harker changed our perception of carbon media when he used a spectrophotometer to measure its effectiveness in removing Gelbstoff (http://www.pets-warehouse.com/carbon.htm). I'm sure that we have better methods today but it starts with one aquarist.

Check this out (http://www.springerlink.com/content/7102263388112811/) - "An automated colorimetric method for the determination of dissolved organic carbon in sea water by U.V. destruction:"

"Summary A fast (30 samples/hour) and precise method is described, which can be used for both sea and fresh water in measuring dissolved organic carbon over a range of 0,1â€"œ10 mg C/liter. At this moment we are testing the efficiency of this D.O.C. analyser against flame ionization detection system."
 
One way that the cichlid breeders came up with to test their water for when it needed a water change was to print out a gradient of yellow shades on a sheet of paper... very intense yellow to very saturated yellow, and white of course. Then they stuck this sheet to back of the tank, and gave it a scale... 1-20. When the water would become so yellow that you couldnt see say... 5 or 10 on the scale... you knew it was time to change the water. Its a layman's spectrometer, FWIW. I was thinking that maybe this could be the criteria for a skimmer 'skim-off' as well... but then you would also need hundreds of gallons of saltwater, either NSW or used synthetic, to use as a scale.

Anways, Beananimal... I remember multiple posts where people would report that simply drawing their air from the outside would improve their skimming. If the air is dryer, warmer, or cooler... I dont know, but one thing was reported among most... their pH was higher than with the 'room air' being used. I would suspect ORP was changed as well. So I tried it as well... running my skimmer intake through the window nearby... sure enough... my pH shot up even higher than the regular internal air... and my system doesnt bleed into the room since the canopy is vented to the outside, so its not because of tank heat or humidity. Higher CO2 could be part of it, and at some point, maybe o2 as well... Im not sure... but there is something to that little change.

I suppose it makes sense... think about ozonizers... a mere 200mg/hr is enough for most skimmers (heck, most people I know only run 50 and thats plenty)... and considering the total throughput of air, thats less than 1%, isnt it? If less than 1% ozone is enough to alter our skimming, maybe a 1% change in oxygen is as well.
 
Well, yes it would...lol. Just saying... its another variable just like altitude... a skimmer in denver may not work the same as a skimmer in the lowlands of New Mexico.
 
I am confused as to what you are testing for with the salifert test. If you are going to really test the water use a gc-mass spectrometer. Of course you must know what "peaks" you are looking for, which are yet to be described in this thread.. I run a bm200 on 90 gallons, no carbon, no ozone, no yellow water. So in my case the BM200 is enough skimmer. I think the abiltiy of any skimmer is limited to how the tank is set up, proper flow rates, display turnover, etc. Way too many variables to say "this is the one". Its so simple and cheap to use carbon that buying a skimmer for this specific purpose seems to be an effort in futility. Is there a specific compound you are testing for, DOC covers anything with a carbon molecule in it, kinda wide open. In the real world of chemistry those salifert tests and cheap calorimeter's are really not going to tell you much.
 
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