A protein skimmer or foam fractionator is a device used mostly in saltwater aquaria to get rid of organic compounds from the water before they decompose into nitrogenous waste.

Next to primary biological filtration, foam fractionating, better known as protein skimming, is the next most important aspect of any healthy marine system. Although there are systems that claim to be "skimmer-free", for most of us dissolved organic compounds, phenol oils, and other yellowing agents are a pain in the neck that only active protein skimming can get rid of.

Protein Skimmers are an first-class accessory to the marine fish tank. Protein skimming is the exclusive form of filtration that physically removes organic compounds before they start to break down, reducing the burden on the biological filter and improving the water's oxidation-reduction potential. The fundamental principle of protein skimmers is to effervesce or foam the water so that the muck and waste bi-products get collected and you are able to dispose of it.

There are many different types of protein skimmers available on the market. The most widely used is the needle wheel or pin wheel protein skimmer. This is a small connector which is placed over the water pump and churns the water to create the necessary foam. This is widely believed as the best form of foam fractionalisation. Other methods available are air stone based or high pressure direction nozzles

Before we look into the subject matter any deeper, let's talk about how these products function.

To be as unscientific and as clear-cut as possible, let's just say that the air bubbles inside the skimmer's body strip the water of undesirable waste by-products. How the bubbles accomplish this is a neat trick that needs some explanation.

It was discovered long ago in waste treatment plants that by injecting high volumes of air bubbles into a column of waste water, the resulting effluent was purer and much cleaner than before. And this is all down to surface tension. This is the interaction between the oxygen bubble and the surrounding water which creates a kind of friction between the two. This friction in turn "charges" the molecules in the water.

Playing on the old Physics Law of "opposites attract", the charged gunk molecules "stick" to the bubbles, riding them up the column of water. Once the bubbles reach the surface air they burst, depositing their hitchhikers into a collection cup. This collection cup keeps the accumulated gunk from slipping back down into the water column inside the reaction chamber.

The larger the volume of air and the smaller the bubbles then the more surface area there is to attract the proteins and the more efficient the skimmer.

So a Protein Skimmer really does help with keeping your water quality to a good standard as well as keep your fish healthy.