ARM 37.115.1308. WATER CHEMISTRY PARAMETERS

(1) Water chemistry, temperature, and clarity measurements must fall within the parameters set forth in Table 6: (2) If total alkalinity is too low, it will result in pH bounce and a tendency to cause corrosion. If total alkalinity is too high, it will result in cloudy water increased scaling potential and a tendency for pH to be too high. (3) Whenever isocyanurates or cyanuric acid (CYA) are used in a pool, spa, or other water feature, the concentrations of CYA shall not exceed 50 ppm. Recommended levels of CYA are 25-30 ppm. After March 1, 2010, isocyanurates or cyanuric acid shall not be used in newly constructed or renovated indoor pools, indoor spas, or other indoor water features or when a chlorinator is replaced. Licenseholders of indoor pools, spas, or other water features currently using isocyanurates or cyanuric acid shall have one year from March 1, 2010 to convert to a nonstabilized type of disinfectant. Table 6. Parameter Acceptable range Ideal range Maximum Chlorine 2-8ppm 3-5ppm 8ppm Combined chlorine 0 to 0.5ppm 0.0 0.5ppm Bromine 2-10ppm 2-8ppm 10ppm Total Alkalinity 60-220ppm (varies by chemical type and pool surface) 80-100ppm for Cal Hypo, lithium hypo, and sodium hypochlorite; 100-120ppm for Sodium dichlor, trichlor, chlorine gas and bromine compounds 220ppm Oxygen Reduction Potential (ORP or HRR, which stands for High Resolution Reduction) 650 minimum millivolts (mV) 650-750 minimum millivolts (mV) no maximum pH 7.2-7.8 7.4-7.6 7.2-7.8 for all pools, spas, or other water features except flow through hot springs, which may have a pH up to 9.4 Cyanuric Acid (allowed only in outdoor pools) 0-100ppm 10-50ppm 100ppm Calcium Hardness Pools 150-1,000ppm Pools 200-400ppm; Spas 150-250ppm Pools 1,000ppm Spas 800ppm Temperature Varies Varies Spas 104ºF Pools 100ºF EXCEPTION: flow through hot spring pools and spas, which may have a maximum temperature of 100ºF and 106ºF Clarity In the deepest part of the pool, spa, or other water feature, the main drain shall be clearly visible and sharply defined. NTUs must be in the range of 0.0-1.0 In the deepest part of the pool, spa, or other water feature, the main drain shall be clearly visible and sharply defined. NTUs must be less than .5 NTUs up to 1.0