Improved podcasts and techniques that facilitate their use are disclosed. The fluorescence response at the different treating agent dosages is used to determine whether the system is overdosed or underdosed on a continuous basis and to control treating agent dose accordingly. One such performance metric is an expected time for completion of the task. The hub has a first port and a second port. The connective aluminum shape provides a rapid and secure attachment for a plurality of glass panes to a curtain wall frame supporting structure.