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View Full Version : Skimmers Don't Remove Organics



SantaMonica
01-26-2009, 08:07 PM
New Research on Skimmers and Organics:

The whole point of scrubbers is that they remove Inorganic Nitrate and Inorganic Phosphate, which are the things your test kits measure, and which are also the things that cause nuisance algae to grow. The other good point about scrubbers is that they leave Organics (food) in the water for the corals and fish and bacteria to eat (the bacteria also then become coral food.) People who prefer skimmers, however, say that skimmers removes Organics (food) before they break down into Inorganic Nitrate and Inorganic Phosphate.

I say, why not just feed less, instead of feeding more and then removing it with a skimmer? Let's look at it from their viewpoint. Their viewpoint is "Feed more, and remove the excess Organics (food) with the skimmer." Well, the current January 2009 issue of Advanced Aquarist just published extensive research into how well different skimmers remove Organics. They refer to Organics as "TOC", which is the Total Organic Carbon; TOC is the the combination of Dissolved Organic Carbon (DOC), and Particulate Organic Carbon (POC). Here is the article, and this is what it said:

http://www.advancedaquarist.com/2009/1/aafeature2

"In addition to some dissolved organics, small particulates and microbes (bacterioplankton, phytoplankton) can be removed at the air/water interface of the [skimmer] bubble as well (Suzuki, 2008). The skimming process does not remove atoms/molecules that are strictly polar and readily dissolve in water, such as some organics, salts, inorganic phosphate, carbonate, etc.

"The skimmer pulls out all of the TOC that it is going to remove by the 50-minute mark. Beyond that time point, nothing much is happening, and the TOC level doesn't change much.

"Thus, all skimmers tested remove around 20 - 30% of the TOC in the aquarium water, and that's it; 70 - 80% of the measurable TOC is left behind unperturbed by the skimming process. It may be possible to develop a rationalization for this unexpected behavior by referring back to Fig. 1. Perhaps only 20 - 30% of the organic species in the aquarium water meet the hydrophobic requirements for bubble capture, whereas the remaining 70-80%, for whatever reason, don't."

So, the strength of skimmers (since they don't remove Inorganics) is supposed to be that they remove Organics before they break down. But this research shows (once again) that they don't even remove the Organics. Here is additional 2008 reasearch that shows the same:

http://www.advancedaquarist.com/2008/8/aafeature3
http://www.advancedaquarist.com/2008/9/aafeature2