The basic reason a pool turns green is algae begins to bloom. Here in the Valley of the Sun, a simple monsoon dust storm can turn a bright, clear pool to a cloudy green one in just 24 hours. Leaves, dust, and other debris quickly tax the chemical balance of the pool and allow algae to take advantage. Pools and spas in vacation homes and bank-owned properties are especially susceptible to turning green and staying that way for far too long.
Neglected and infrequently used pools and spas that turn murky green become breeding grounds for disease-carrying mosquitoes, bacteria, fungi, and other microorganisms. The murky water hides debris and is very dangerous for animals and people who may fall in. Maricopa County is constantly trying to control mosquitoes carrying West Nile Virus and has taken to chemically fogging large areas to combat the pests. Green pools present a health hazard to the entire community and the county has been cracking down by prosecuting violations and assessing fines.
