Protein skimmer

A protein skimmer or foam fractionator is a device used to remove organic compounds such as food and waste particles from water.

Due to their intrinsic charge, water-borne proteins are either repelled or attracted by the air–water interface and these molecules can be described as hydrophobic (such as fats or oils) or hydrophilic (such as salt, sugar, ammonia, most amino acids, and most inorganic compounds).

These include a variety of fats, fatty acids, carbohydrates, metals such as copper, and trace elements such as iodine.

Alternative forms of water filtration have recently come into use, including the algae scrubber, which leaves food particles in the water for corals and small fish to consume, but removes the noxious compounds including ammonia, nitrite, nitrate, and phosphate that protein skimmers do not remove.

All skimmers have key features in common: water flows through a chamber and is brought into contact with a column of fine bubbles.

The material that collects in the cup can range from pale greenish-yellow, watery liquid to a thick black tar.

Originally designed by Klaus Jensen in 2004, the concept was founded on the principle that a conical body allows the foam to accumulate more steadily through a gently sloping transition.

Because the air bubbles may be in contact with the water for a longer period in a counter-current flow system, protein skimmers of this type are considered by some to be more effective at removing organic wastes.

[8] The original method of protein skimming, running pressurized air through a diffuser to produce large quantities of microbubbles, remains a viable, effective, and economic choice, although newer technologies may require lower maintenance.

Air stone protein skimmers may be constructed as a DIY project from pvc pipes and fittings at low cost [1] [2] and with varying degrees of complexity [3].

The premise behind these skimmers is that a high-pressure pump, combined with a venturi, can be used to introduce the bubbles into the water stream.

The tank water is pumped through the venturi, in which fine bubbles are introduced via pressure differential, then enters the skimmer body.

Needle-wheel describes the look of an impeller that consists of a series of pins projecting out perpendicular to the rotor from a central axis.

Mesh-wheel describes the look of an impeller that consists of a mesh material attached to a plate or central axis on the rotor.

The proprietary design is protected in the United States with patents and commercial skimmer products in the US are limited to that single company.

This method is related to the downdraft, but uses a pump to power a spray nozzle, fixed a few inches above the water level.

The spray action entraps and shreds the air in the base of the unit, similar to holding your thumb over a garden hose, which then rises to the collection chamber.

While there is a popular belief among some aquarist that this recirculation increases the dwell or contact time of the generated air bubbles within the skimmer there is no authoritative evidence that this is true.

With a recirculating design, the one inlet is usually driven by a separate feed pump, or in some cases may be gravity fed, to receive the dirty water to process, while the pump providing the foam or air–water mix into the reaction chamber is set up separately in a closed loop on the side of the skimmer.