BioGuard Lo N Slo is a pH decreaser that reduces pH and total alkalinity in pool water. This product is generally easier to use and store than liquid muriatic acid. Keeping your pool’s pH level balanced is not only crucial for swimmer comfort; it also helps keep your equipment and pool finish in good condition. Swimmers may return to the pool only 15 minutes after application. You can slowly and safely reduce pH and total alkalinity with Lo N Slo.