Nicknamed 'NESI' by the facility staff both because of its large size and slight resemblance to the mythical Lochness Monster, this WeirWasher Automated Cleaning System also has the important ability to submerge, resurface, and telescope. These motions are necessary to control the prolific algal growth on the weirs and effluent launder in the circular secondary clarifier. The spray apparatus must be able to pass under radial tank components and then resurface back into position to continue cleaning after the obstacle is passed. Additional telescoping motion is necessary to access the trough design as it extends at the corners of this octagonal launder configuration. The tank size and extreme temperature health risks prevent staff from cleaning this design. The potential health considerations prompted this installation. The WeirWasher successfully cleans the daily algae growth from the effluent launder with the ducking surface scum skimmer radial trough design.