I frequently need to delay an output for a balcony or rear-of-the-room fill. I was thinking of looking for one of those old Behringer Shark things to keep in the DL1608 kit, until I realized the Mackie already has the capability, if you can spare the delay effect and an aux.
Select the Delay send and run all the channels up to 0. BTW, a less frustrating way of setting a fader to 0 is to select the fader, select the edit box, backspace everything away and hit Done. In the main mix, run the Delay channel down to -inf. Pick a spare Aux, set it to Pre, and run only the Delay channel up to 0. That Aux is now your delayed output. It's already mono and also has dedicated EQ. On the Reverb/Delay page, select Mono Delay, Set the Feedback to 0, the Damping to 20k, and the Delay Time to whatever you need. You can stand up in the balcony and adjust everything to taste.
Job done.
