(1) An operator of any pool, spa, or other water feature that has installed an ORP meter shall use the ORP as an indicator of disinfectant level.

(2) An ORP meter must be properly maintained in compliance with the manufacturer's recommendations for the routine periodic maintenance of the ORP sensor.

(3) ORP readouts may be used as an indicator of disinfectant level following the manual water testing prior to opening.

(4) Daily record logs must include manual water testing results before opening and ORP reading every four hours after opening and at closing every day.

(5) The water in the pool, spa, or other water feature shall be closed if the ORP is less than 650 mV as measured by the controller or by the ORP measuring equipment, regardless of the chlorine residual measurement and it shall remain closed until the ORP is at least 650 mV.