Guest Column - September 2007
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A Balancing Act

By Robert Hedrick

orrect water balance in commercial pools and spas can make the difference between having a safe, attractive pool and a disaster. Advances in chemical automation, the development of new methods of disinfection and better education on the problems associated with water chemistry have made the aquatics facility manager's job easier while providing safer water to the bather.

Chemical automation using direct connections from microprocessor-based programmable controllers to a wireless Internet-based database management system provides "real time" information regarding water chemistry. Programmable controllers have now become the reporting media, transferring information from the aquatic facility to a "readily accessible" record of the pool's current and past status. This offers the aquatics facility manager better monitoring and control of the chemical balance with more accuracy than at any time in the past. A new age of management and control of commercial pools is at hand, waiting only to be applied.

Technological advancements in microprocessor-based programmable controllers with wireless Internet connectivity allow for the customization of each chemical feed and monitoring system, depending on the individual facility's pool, spa and water feature requirements.

A single controller can control and report the status of up to three bodies of water with numerous options that have never before been available to the facility aquatics manager. Not only can these controllers maintain chemical balance, but they have now become an important "full equipment room" reporting system that keeps the aquatics manager fully aware—in real time—of the safety of the facility.

From primary to secondary disinfection

Primary disinfection using sodium hypochlorite, calcium hypochlorite, bromine, di-chlor, trichlor or chlorine generation (salt systems) has always been a part of the automation of commercial pools and spas. pH control has always been a part of the automation system.

It no longer stops here.

More and more often, the industry is seeing the need for a secondary disinfection system to act as a backup to the primary system. Controllers now control, manage and support the use of UV systems, and tablet, granular or generation chlorination systems as the backup to the primary disinfection method chosen by the architect or designer for the facility.

Controlling chloramines

In addition to the basics, controllers also allow for the correction of the water balance and removal of combined chlorine (chloramines) from the water. In indoor facilities, the same system can remove the chloramines from the air surrounding the water. Advanced technologies allow for the measure of the total chlorine, free chlorine and combined chlorine using a highly accurate optical (colorimetric) controller, which automatically takes a DPD test.

Knowing the combined chlorine level allows for the controller feed of an enzyme followed by a shock treatment based upon the combined chlorine test. This testing and treatment can be scheduled at a time and date when no bathers are in the pool and starts automatically. The colorimetric system is connected directly to the controller, providing a true PPM reading not subject to the problems associated with PPM sensors.

Using a DPD colorimetric chlorine measurement system, a water test is automatically taken in a preprogrammed frequency as often as every 15 minutes. Reagents are automatically mixed with a sample of pool water and are then optically read to determine total chlorine, free chlorine and combined chlorine levels. A true PPM reading is then transmitted through the controller to the Internet-based data management system. Once this is done, the controller can adjust the chlorine level according to a pre-programmed time and date and reduce the chloramines levels in the water by reaching break-point chlorination and eliminating the chloramines levels to zero. At the same time, the controller opens the air handlers in indoor facilities to remove chloramines from the air, thereby preventing precipitation of chloramines back into the pool water.