"The Pooltester allows simultaneous determination of the most popular water treatment agents and the pH value.","pH value The pH value of pool & spa water should generally be between the slightly acidic value of 6.5 and the slightly basic value of 7.6. Due to the use of various water treatment chemicals as well as ambient environmental effects, pool owners have to determine the pH of the water and correct the value as necessary.","Disinfection Nowadays, pool owners can choose from a range of modern water treatment agents that are often used in combination. These water treatment chemicals are only effective within a limited pH range. Therefore in addition to checking the concentration of the water treatment chemicals, the owner\/operator should also monitor the pH value of pool water and adjust it if necessary."