Methods, devices and device components are presented for uniformly treating fluids undergoing mixing with electromagnetic radiation. In one aspect, the present invention provides methods of treating a fluid undergoing continuous fluid mixing wherein net radiant energies necessary to provide uniform treatment of the fluid samples with electromagnetic radiation are calculate on the basis of the volume, mass or mixing rate of the fluid or any combination of these variables. In another aspect, the present invention provides algorithms for determining net radiation energies, radiant powers, and/or illumination times necessary for providing uniform treatment of fluid samples. The present invention provides methods for uniformly reducing pathogens in biological fluids, including blood and blood components.
