The most efficient way to remove dissolved organics from seawater is through the use of a protein skimmer. Protein skimmers remove these organics before they have had a chance to degrade, accumulate, and cause an increase in nitrate and reduction in alkalinity. In addition to removing undesirable water and contamination, protein skimmers also increase oxygen levels and the redox potential of water. It is for these reasons that a protein skimmer is one of the most important pieces of equipment on a salt water aquarium.
 

In order to remove waste, protein skimmers rely on the electrostatic attraction of dissolved organic material to the interface between air and water. By creating bubbles within the protein skimmer, this attraction causes the dissolved organics within the water to stick to the outside surface of the air bubbles. Smaller, more plentiful bubbles have a much larger surface areas than fewer, larger bubbles. So, a greater number of smaller micro bubbles is highly desirable to create a greater total surface area for attracting dissolved organics. In order for the micro bubbles to be effective in attracting dissolved organics, there must be adequate contact time between the micro bubbles and the water traveling through the skimmer. The smaller, more plentiful the bubble and the longer the contact time between the water and micro bubbles, the greater the interface and the more dissolved organics that a skimmer can remove. These micro bubbles then collect at the surface to create foam which is gathered in the collection cup for removal.

Recirculation Skimmers
 
In the past few years, there was an advancement in skimmer technology - the recirculation skimmer. Previously, the needle wheel skimmer pumps would draw water from the tank/sump, inject air, chop the bubble into fine micro bubbles - by way of the needle wheel - and pump the water into the skimmer body. The main draw back to this style of skimmer is that in order to create the amount and consistency of bubble required for adequate skimmate, the pump would have to draw large volumes of water at high flow rates through the skimmer. This means that the bubbles have a very limited contact time in which to remove the dissolved organics in a needle wheel skimmer. This results in the water leaving the skimmer body without having the majority of the dissolved organics removed.  This is where the advancement of the recirculation skimmer is important. Instead of drawing water from the tank/sump, a recirculation skimmer draws its water from within the skimmer body and a separate feed pump is then used to introduce the tank water to the skimmer. By setting this feed pump with a very low flow rate (when compared to the flow rate of the pump used on the skimmer body) the contact time of the air bubble is greatly increased, while still maintaining the same proper volume and size of air being injected into the skimmer via the recirculation pump on the side of the skimmer.

Extreme Skimmers

Recently, there has been improvement in skimmer pump designs from the recirculation skimmer. This new skimmer pump design employs the use of a pin wheel as opposed to a needle wheel and a new air delivery system which is able to inject significantly finer and significantly larger quantities of these fine bubbles into the skimmer body. As this skimmer pump is injecting larger volumes of air, it is also, in turn, injecting smaller quantities of water. It is important to note, that this improvement in pump designs only works well when the intake of the pump is completely unrestricted. The implementation of this new design means that protein skimmer no longer have to be built in a recirculation style and can once again draw water from the tank/sump.

Cone Skimmers
 
An additional advancement in skimmer design came about as it was discovered that when the fine micro bubbles were condensed quickly as they travel up the neck of the collection cup, a great number of them would pop. The waste that these bubbles was transporting upwards towards the collection cup, would then be heading back down again and into the skimmer body. The latest design of skimmer body utilizes a very conical shape and minimal reduction in skimmer body size for the transfer from the skimmer body into the collection cup. When you combine this with the latest improvements in skimmer pump designs you get a skimmer that is best suited for producing an extremely fine micro bubble, in very large quantities along with allowing for an adequate contact time between the water from the aquarium and the micro bubble and the ability to deliver the bubble containing the waste into the collection cup on the skimmer.