Final answer:
Algae growth in a swimming pool is primarily affected by water circulation, but factors like chlorine levels and temperature can also affect the water's pH and contribute indirectly to conditions promoting algae.
Step-by-step explanation:
Algae formation in swimming pool water has the following effect on pH levels: poor water circulation can lead to areas where algae can grow unimpeded. High levels of chlorine, often used to prevent algae growth, typically lower the pH of water, making it more acidic. Cold air temperatures may affect the pool water temperature and, consequently, the rate of chemical reactions, including those that might influence pH. However, the question seems to be oriented towards what specifically contributes to algae growth rather than pH changes.