Guest Column - March 2005
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Avoiding Maintenance Problems in Commercial Pool Care

Four areas to keep in mind

By David Rouse

Probe fouling

As bather load increases, more pollutants such as sweat, lotions and other body oils infiltrate the water. These contaminants collect in the water and form a microscopic coating on the probe, reducing the probe's accuracy—known as probe fouling. The effect is a delay in the probe's ability to detect changes in sanitizer level, as well as causing the controller to display a lower than actual ORP value.

Several automatic cleaning systems have been developed to keep ORP probes free of contaminates and coatings. These systems are readily suited to large commercial applications. Automatic probe cleaning systems clean probes at a preset time interval, such as weekly or daily. However, after physical or chemical cleaning, the ORP probe takes a while to stabilize and forms an oxidative film on the metal sensing surface that allows it to read the electrical potential of the sanitizer and oxidizer in the water. This can result in hours of inaccurate readings and inefficient use of sanitizing and balancing chemicals.

The solution to all these problems is a technology known as continuously cleaning ORP probes, which resolves the problems experienced when using an automatic probe cleaning system. This method cleans the ORP probe constantly, eliminating the need to develop an oxidative film between cleanings and thus allowing ORP probe reading to be consistently accurate. The continuous cleaning probe system solves most ORP probe-fouling problems, even in high bather-load environments and in pool water containing higher levels of cyanuric acid (CYA). It is not a question of whether probes will become fouled with any type of sanitizer used in any type of pool—it is a question of when. With continuous cleaning, this is no longer an unknown variable.

Routine water testing

Pool water testing should be performed routinely to make sure pH, chlorine and other water-balance parameters are balanced. On large-capacity commercial pools, a complete water analysis should be performed at least once a day, including free chlorine residual, total bromine residual, pH, acid and alkali demand. Total alkalinity, CYA, calcium hardness, iron and copper should be checked at least monthly. Check your local health-department codes for guidance on water testing. Keeping the water balanced is essential for proper pool-care maintenance.

As was discussed previously, automatic controllers make maintenance much easier for pool operators as it constantly monitors and displays the chemical levels. A 24-hour monitoring program also can aid in alerting the pool operator through an alarm system in case of a major imbalance.

Four for thought

The lack of correct pool water maintenance can cause commercial pool operators and public-health officials great concern. To avoid situations that might close a pool, operators need to stay mindful of the above four maintenance concerns at all times. Neglecting the pool, its maintenance systems and the chemical levels of the pool can cause major problems, including down time and chemical imbalances that can be costly to correct.

David Rouse is manager of technical services for BioLab Commercial Pool Care and BioLab, Inc. in Lawrenceville, Ga. He can be reached at or visit