Water temperature has a dramatic effect on the amount of chlorine consumed in an outdoor pool. Water temperature also has some effect on an indoor pool, though not nearly as large an effect as it has outdoors. There are a number of reasons for this, most of them indirect effects. Some algae is always getting blow into an outdoor pool that isn't covered. At higher temperatures these small amounts of algae grow more quickly which means that they consume more chlorine before dying off than they do at lower temperatures.
Chlorine can also break down spontaneously. This is fairly slow at normal swimming pool temperatures and concentrations, but starts to be significant at spa temperatures or in bleach bottles (high concentrations). Temperature also affects the rate that UV breaks down chlorine, though that is again a rather small effect.
Chlorine can also break down spontaneously. This is fairly slow at normal swimming pool temperatures and concentrations, but starts to be significant at spa temperatures or in bleach bottles (high concentrations). Temperature also affects the rate that UV breaks down chlorine, though that is again a rather small effect.