The swimming pool in my development has two of the above. They were recently installed and I don't think they are working as the pool always shows trace or less of Cl. I've checked the Cl in the pool jets coming from the pumps/feeders and they show the same. The management just says they must be working-mind your own business. I've been examing the setup and I wonder if they just haven't got the control dial on the feeders in the right position. There is no manual and I can't find one online that shows how to use this dial. Does anyone know how to operate this dial?