Skimmer evaluation ie organic or protein test.

[Mark...]

There are a million skimmer options out there, at many different price points. Wouldn't it be nice if there was a test to see if your skimmer was doing its job. Wouldn't it be nice to have some science behind you skimmer purchase. They all fill up with crap, but are they getting out all the crap you want out? Does your skimmer match your bio load? Is my Tunze 9410 enough for my 180g? Is a $1000 skimmer really better than a $500 skimmer? 100% better?

It just seems when it comes to skimmers you don't really have a true evaluation tool. I wonder if an organic or protein type test would be the answer?

Whats your take?

 

[downbeach]

Some reading:

http://www.reefkeeping.com/issues/2002-06/fm/feature/
http://www.advancedaquarist.com/2009/1/aafeature2
http://www.advancedaquarist.com/2010/1/aafeature#section-4
http://www.advancedaquarist.com/2010/2/aafeature

 

[Mark...]

Read the first two articles and thought the second one was very interesting. So many varibles when it comes to evaluating. I wonder if Consumer reports could do some testing? The conclusions in the second is posted below. Thanks for the read Downbeach!

Conclusions

Protein skimmers have become indispensable for many aquarists who strive to maintain the high water quality necessary to keep stony corals. This singular piece of equipment is typically the second largest expense after the tank itself, and as of this writing, there are at least 23 different skimmer vendors in operation. The advertising that accompanies these products often boasts of superlative performance, but no skimmer manufacturer has offered any quantitative support for their claims, in part because no useful metric for skimmer performance exists. In this article, we introduce two different measures for skimmer performance; (1) how fast the skimmer removes organic matter from salt water, and (2) how much of the existing organic material actually is removed. We demonstrate how these quantities can be obtained via experimental measurement and mathematical modeling on a model system consisting of Bovine Serum Albumin (BSA) in freshly prepared saltwater. In addition, we demonstrate that the trends among the numerical values obtained in the BSA model system also are observed with TOC removal from authentic aquarium (reef tank) water. The correlation between the BSA model system results and the TOC reef tank water results supports the hypothesis that BSA in saltwater can be used as an effective surrogate for TOC in aquarium water.

Four skimmers having four different reaction chamber volumes and representing four distinct types of bubble generation (needlewheel, venturi, airstone, and downdraft) were tested under the manufacturers' specified conditions. These tests revealed that there was no demonstrable difference between the Euroreef CS80 needlewheel skimmer, the Precision Marine ES100 venturi skimmer, the Precision Marine AP624 airstone skimmer, and the ETSS evolution 500 downdraft skimmer with respect to the rate constant for either TOC or BSA removal. Thus it is fair to conclude that, at least for the skimmers tested under the specified conditions, the individual manufacturers' claims of superior performance are without merit. Whether this conclusion can be extended to other skimmers remains to be seen.

Two operational parameters were examined; airflow rate and water flow rate. For the one skimmer tested at different airflow rates (Precision Marine AP624), the rate constant k for BSA removal did increase significantly as air velocity increased. The performance response upon varying water flow rate was not unequivocal. Using the Precision Marine AP624 airstone skimmer as a test system, increasing the water flow rate at first increased, and then decreased, the rate constant k. The basis for these divergent results has not yet been elucidated.

All four skimmers were quite similar in the second performance figure-of-merit, the total amount of organics removed. The skimmers typically removed greater than 80% of the BSA. In contrast, perhaps one of the more interesting observations to emerge from these studies is the fact that all four skimmers tested removed only 20 - 30% of the total organics present in authentic reef tank water.

Several critical questions that cannot yet be answered concern the generality of the conclusions drawn above. Can any skimmer beat the 30% organic removal level, or is that an intrinsic property of the TOC (cf. Fig. 1)? What are the effects of either gas flow rates or water flow rates that are far outside of the examined range, on k? Are there other unrecognized factors buried in the "k" term involved in determining skimmer performance? These questions can only be answered by examining more skimmers under a wider range of conditions.

From a different perspective, the methodology introduced in this article, in particular the BSA model system, presents a real opportunity for skimmer designers/manufacturers actually to optimize skimmer design/operational parameters in a deliberate and rational manner. Through these types of product development studies, skimmer manufacturers finally might be able to include descriptors in their advertising such as "best", "fastest" etc. that really mean something.

 

[Mark...]

In article 3 the cheapest skimmer removed the most in their study. I'm still not seeing a way to know if any skimmer can max out organics or protein on a given aquarium. It also seems we can only get about 30% max of waste out at best. Over 30 days the organic kept rising and were not removed.

 

[redfishbluefish]

I haven't read the articles, but what has me immediately scratching my head is that if a skimmer can, at best, only get out 30% of the crap, why have I also heard that you don't want to over skim and strip you tank. So if you get your tank down by 30% less, is it now stripped? And it also brings up another question....is have some waste proteins floating around your tank a good thing?

 

[Mark...]

I haven't read the articles, but what has me immediately scratching my head is that if a skimmer can, at best, only get out 30% of the crap, why have I also heard that you don't want to over skim and strip you tank. So if you get your tank down by 30% less, is it now stripped? And it also brings up another question....is have some waste proteins floating around your tank a good thing?

In article 3:

One of the more surprising and important observations to emerge from the earlier skimmer studies was that the four original skimmers tested removed only 20 - 30% of the measurable TOC in the reef tank water examined; the remaining 70 - 80% of the TOC was not removed by skimming. Extension of these measurements to the three new skimmers tested in this study did not add much to the argument. The Reef Octopus' removal amount fell within this range, whereas the Bubble King and Royal Exclusiv skimmers appeared to remove incrementally more of the extant TOC, perhaps up to the mid-30% range. An explanation for this observation was offered in the January 2009 Advanced Aquarist article; in summary, skimmers can only remove what bubbles trap, and bubbles only trap molecules and/or particles (i.e., bacteria, diatoms, etc.) with some compelling thermodynamic reason to adhere to the bubble's surface. On the molecular level, this surface association is typically driven by the molecule/particle having a hydrophobic (= water hating) patch that can be buried in the bubble surface/interior. This arrangement avoids the energetically penalizing juxtaposition of hydrophobic surfaces with (hydrophilic) water, and so overall the system energy is lowered (a favorable occurrence). Some of the molecules/particles in aquarium water will meet this hydrophobic region criterion, and some will not. The ones that do not have a sufficiently large hydrophobic patch will not interact with bubbles, and hence will not be removed by skimming. From, the results of the experiments described here, it appears that only 20 - 35 % of the measurable TOC meets this hydrophobicity criterion (= [TOCl] defined earlier) whereas the remaining 65 - 80 % does not (= [TOCr] defined earlier). In essence, bubbles are a rather poor media for removal of organic nutrients from aquarium water compared to, for example, GAC. However, they do have the distinct benefit of being cheap.

Two meaningful conclusions can be drawn upon examination of these data. First and foremost, the TOC level does increase over time. Thus, neither microbial action nor skimming removes all of the accumulating TOC. Second, the less presumptuous downdraft skimmer appears to do a better job at holding TOC levels lower over the course of a month compared to the Bubble King clone. In more quantitative terms, the aggregate TOC values averaged for both skimmers increase from about 0.53 ppm of C at T = 0 to about 0.95 ppm of C at T = 30 days; a 79% increase! If Sanjay would have performed water changes of just 10% at 7, 14, 21, and 28 days during this experimental time course, the TOC level would have increased to only 0.66 ppm of C - a 25% increase. Thus, this experiment illustrates the importance of conducting regular water changes as a means to keep organic nutrients in check.


I wonder what per cent if any is phosphates in the equation and if so what per cent. Also what percent if any does carbon remove...

Edit: Article 4 stated phosphates do concentrate in skimate.