An owner or operator shall ensure that the water chemistry of a public pool or spa is maintained according to the following requirements: The pH of the water is maintained between 7.2 and 7.8; The total alkalinity of the water is maintained between 60 ppm and 180 ppm; The calcium hardness of the water is maintained between 150 and 400 ppm; The Langelier Saturation Index of the water is maintained between -0.5 and +0.5 as calculated by: The Langelier Saturation Index formula: Langelier Saturation Index = pH + TF + CF + AF - 12.1 where: TF = temperature factor, CF = calcium hardness factor, and AF = alkalinity factor, and The following factor table: The amount of total dissolved solids is maintained so that it does not exceed 1,500 ppm, except for a salt water pool where the total dissolved solids may not exceed 3,000 ppm; The amount of dissolved metals is maintained so that it does not exceed the following levels: Iron, 0.3 ppm, Manganese, 0.3 ppm, and Copper, 1.3 ppm; and The water clarity is maintained so that either a 6 inch seechi disc placed in the deepest part of a pool or spa or the main drain is clearly visible and sharply defined when observed from the side of the pool or spa. An owner or operator shall ensure that: Water additives and treatment chemicals are used according to manufacturers' instructions; and When chemicals are added directly to a pool or spa, no one is allowed in the water until the chemicals are dissolved and diffused throughout the pool or spa. An owner or operator shall ensure that the water temperature for a heated public pool or spa does not exceed: 88°F for a pool; 104°F for a spa; and 96°F for a therapy pool.