Pool & Spa

Pool Water pH:

Maintaining the proper pool water pH is essential for bather comfort, equipment maintenance, and chlorine functioning. The ideal pH for pool water is typically between 7.2 and 7.8. A pH value outside of this range may cause issues, including:

• Bather discomfort due to skin and eye irritation (pH < 7.2 or 7.8 < pH
• Decreased longevity of pipes and filters due to corrosion (pH < 7.2)
• Reduced sanitization activity of chlorine (7.8 < pH)

Chlorine Sanitization Activity:

The amount of chlorine needed to keep pool water clean depends on many different factors. When more swimmers are in the pool, the concentration must be higher to adjust for heavier contamination. Intense sunlight can reduce chlorine effectiveness, requiring higher concentrations for sanitation. The pH of pool water impacts chlorine activity by affecting the equilibrium concentration of hypochlorite ion and hypochlorous acid. When pool water pH is too high, hypochlorous acid concentration is reduced. Consequently, chlorine is less effective at oxidizing contaminants, because it is not present in its most active form. The equilibrium reaction below demonstrates this effect:

A complete pool water monitoring system typically includes a pH sensor, an ORP sensor, and a controller. The controller adjusts the amount of chlorine and other chemicals added to the pool based on inputs from the pH and ORP sensors. This type of set up, illustrated in more detail below, is ideal for automatic adjustments, as factors such as sunlight and bather load fluctuate monthly, daily, and even hourly.

INSTALLATION TIPS

Choosing the Right ORP Sensor:
For the most accurate ORP measurements, Sensorex recommends following industry standards for the type of ORP measuring surface:

• Probes with standard platinum tips are recommended for regular chlorine pools
• Probes with gold tips are recommended for salt water chlorine pools

Grounding:
Due to the large amount of plastic piping in typical pool systems, proper grounding is essential to prevent sensor inaccuracy and extend lifetime. Stray electrical current will be attracted to the sensor if the system is not properly grounded.

SPECIAL SENSOR REQUIREMENTS

Direct Fit Replacements:
If your pool chemistry monitoring system has already been operating for some time, you may need replacement sensors. Sensorex offers a range of direct fit replacement sensors for pool and spa applications. Contact us to find the right sensor to retrofit your system.