Aug 26, 2015 · Oxygen and carbon dioxide move across cell membranes via simple diffusion, a process that requires no energy input and is driven by differences in concentration on either side of the cell membrane. Simple diffusion is responsible for the spread of an air freshener through a room, or of a few drops of dye to eventually turn a glass of water a uniform color. Molecules naturally disperse from ... It can also be resistant to chlorine, making it more difficult to remove. Mustard algae can grow unnoticed in your pool filter and adhere to anything that enters the swimming pool (swimsuits, toys, skimmer baskets, poles, nets, brushes and more), so it is important to clean everything thoroughly to prevent it from re-entering the water.