The apparatus in first aspect comprises: ozone device (100) comprising ozone operating system (115)； ozone distribution line (118), a proximal end of which is connected to ozone operating system (115)； and connector unit (130) for connecting ozone device (100) to CPAP device (105), comprising: first end connecting to proximal end of a hose (124) of the CPAP device (105), and comprising first opening； and second end connecting to water reservoir (122)； connector unit (130) being configured such that when installed into reservoir (122), distribution line (118) traverses connector unit (130), extending through second opening so as to distribute ozone generated by ozone device (100) into reservoir (122). The connector unit in second aspect comprises: first end connecting to proximal end of hose (124) of CPAP device (105), first end comprising a first opening； second end connecting to water reservoir (122), second end comprising second opening； and wall between first end and second end； connector unit (130) being configured to receive ozone distribution line (118) for distributing ozone gas into CPAP device (105), such that distribution line (118) traverses wall and when connector unit (130) is installed in water reservoir (122), free end of distribution line (118) passes through second opening and is disposed within reservoir (122).
