Filtration - Protein skimmer

The protein skimmer (foam fractionators) can be thought of as the only filtration equipment that can remove organic pollution from sea water before it breaks down into nitrogenous waste. It effectively reduces the burden on other filtration equipment and is usually placed in the system before any other forms of filtration.

Skimmers introduce large volumes of air as small air bubbles into a column of water. Organic compounds stick to the bubbles that eventually float to the surface and produces foam. This foam heavily laden with organic compounds then overflows into a collection cup, thus removing organics from the water column. The compounds removed by this method are fats, fatty acids, carbohydrates, metals such as copper and trace elements such as iodine and also bacteria and particulates.

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Protein skimmer diagram

How it works

Refer to the diagram.

1. Water from the aquarium enters the water inlet tube.

2. The pump drags in a mixture of air and water.

3. The pump impeller a high speed rips the bubbles apart to give finer bubbles and pump the mixture into the water column.

4. The bubbles rise collection organic compounds on their way to the surface.

5. A the surface the bubbles burst releasing organic compounds or to create larger bubbles

6. New bubbles contiuously arrive at the surface.

7. Eventually a stable foam laden with organics is formed

8. The foam rises above the waterline and overflows into the cup.

9. After a period of time the cup foam bubbles burst and form a brown oily fluid at the bottom of the collection cup.

10. Note :- Water exiting the skimmer will have less organic contaminants when compared to the water intering the skimmer.

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There are many designs of skimmers. Different shapes, water flow methods and air injection methods. The photos below show skimmers from different manufactures.

Your choice of skimmer will depend on cost and size requirement. Skimmer size relates to aquarium size.

Two skimmer designs - randomly chosen