What is commonly added to a pool to reduce chlorine odor?

Cyanuric acid is commonly added to swimming pools to stabilize chlorine, which in turn helps to reduce the chlorine odor. When chlorine is exposed to sunlight, it can dissipate quickly, leading to lower available chlorine levels and a stronger odor as it breaks down. By adding cyanuric acid, the chlorine becomes more protected from UV radiation, allowing for longer-lasting effectiveness and a reduction in the noticeable odor associated with chlorine. This stabilizing effect can help to maintain a more pleasant swimming environment and ensure that the chlorination process continues to work efficiently.

The other options do not serve the same purpose. Algaecide is used primarily for controlling algae growth and does not directly impact chlorine odor. Stabilizer is a generic term that can sometimes refer to cyanuric acid but is not specific enough in this context. A pH increaser adjusts the acidity level of the pool water but does not influence chlorine odor or stability. Thus, cyanuric acid is the preferred choice to help manage chlorine levels and mitigate odor in pool water.