You will not use any water while using the VirtuCLEAN. Your VirtuCLEAN unit will disinfect and sanitize your CPAP equipment without any cleaners or liquids. Though the VirtuCLEAN does disinfect your gear, it will not remove any residue or build up that using non-recommended water in the humidifier reservoir. When filling the humidifier chamber on your CPAP machine, you will always want to follow all of the manufacturer’s suggestions. Not following the recommendations provided by your manufacturer could damage your device.