In a method for the simultaneous application of at least two application media to a moving material web, more particularly a paper or cardboard web, by means of a curtain applicator unit having a nozzle installation comprising at least two nozzles, a first nozzle delivers a first application medium and a second nozzle delivers a second application medium, the two application media being delivered,during normal operation, under the force of gravity, in the form of a multiple application curtain onto the moving material web, and the treatment of the material web with application medium being interrupted by means of a channel arrangement during standby operation. In standby operation, the channel arrangement or nozzle installation, or a guide plate, in particular a swivellable guide plate, is moved into a first position, in which only the first application medium passes from the first nozzle via the nozzle installation into the channel arrangement; the first application medium collectedin the channel arrangement is passed back to the first nozzle, in particular via a first working vessel, to form a first closed circuit; and the second application medium is returned to the second nozzle via at least one bypass directly from the second nozzle, and in particular via a second working vessel, to form a second closed circuit.