“California Polytechnic State University’s National Pool Industry Research Center conducted a study examining the rise of pH levels in swimming pools sanitized with salt.
Researchers tested pH levels every Monday, Wednesday and Friday over the course of several weeks. pH was adjusted to 7.4 after every Friday reading. Over the weekend, pH spiked from 7.4 to 8.0.
The pH in a pool or spa impacts the sanitizer efficacy of chlorine tremendously. For example, at a pH of 7.2, chlorine is 65 percent effective; at 7.8, 32 percent effective; and at 8.0, 20 percent. As you can see, chlorine effectiveness decreases dramatically as the pH in water increases.
This study tells us two things: The first is that salt generators will cause the pH in a pool to rise quickly. The second is that once-a-week testing and adjustment is not enough to maintain proper pH levels.”
-Robert Flynn (www.poolspanews.com)