Although the pH and total alkalinity measurements are the same, the sanitizer level (bromine or chlorine) should be kept between 3-5 ppm. In a spa, the filter requires more frequent cleanings. In addition, the water will require more frequent care to assure pH and sanitizer levels are correct. For further details, please see our spa care guides for Leisure Time, Robarb, or GLB’s Rendezvous spa line.