Chlorine generation through salt is continuing to make its presence known in the residential pool industry. We have seen a trend shift in our service company to where more than 60% of the pools we service and over 90% of the pools we build now have chlorine generation of some form in use. Technology is continually being developed and integrated with chlorine generation to bring new levels of automation and ease to the backyard pool. An example of this would be Hayward Pool Products Sense and Dispense ORP and pH controller.
First let us talk about salt generation and how it works in simplified terms. Special blends of pure salt are added to your swimming pool, most units operate at a range of 3000ppm – 3600ppm (this equates to anywhere from 150lbs upwards of 500lbs of salt dependent on the pools gallonage). This is enough salt to feel its soothing affects on your skin as well as offering just a hint of saline taste in the pool’s water.
Then a electrolytic cell is installed in line with your plumbing that turns the salt into the same sanitizing chemical created by an eroding puck, stick or bag of chlorine shock; Hypochlorus Acid. The cell is often controlled by a box either offering a digital interface or analog dials to adjust the level of chlorine generated. With these traditional units it is necessary to test for free chlorine and adjust the output as to not over or under produce chlorine for the pool.
One other thing that should be known is that pools utilizing chlorine generation will have a tendency to have a higher pH as opposed to a pool using compressed chlorine (sticks & pucks). High pH interferes with chlorine’s ability to sanitize a pool. Even though you may have a good testable level of free chlorine, it can be rendered ineffective by a pH of 8.0 or higher.
The beauty of the Sense and Dispense automation is in its ability to control these two aspects of chlorine generation. ORP is a way of electrically measuring the water’s ability to sanitize itself. As chlorine builds in the water (assuming the pH stays the same) the ORP level will begin to rise or adversely drop if the chlorine level diminishes. Since the Sense and Dispense can monitor ORP levels it can automatically adjust the output of the chlorine generator for the demand of sanitizer in the water. This automation ensures optimum longevity on your electrolytic cell.
These units also can monitor the water’s pH and can inject CO2 gas or liquid acid into the water to control the pH drift associated with a chlorine generation unit. If this technology is further coupled with an ozone generator and borates you can create a swimming pool that truly requires very little water balance maintenance.