Protein skimmer removes certain compounds, including proteins and amino acids found in food particles, by using the polarity of protein itself. Due to their intrinsic charge, water-borne proteins are either repelled or attracted by the air/water interface and these molecule can be described as hydrophilic. A good skimmer pump will generating a large air/water interface, specifically by injecting large numbers of bubbles into the water column. The smaller the bubbles the more effective the protein skimmer is because the surface area of small bubbles occupying the same volume is much greater than the same volume of larger bubbles.