Do you have a keyboard with vocal harmonizer like PSR2000 or PSR2100 ?

I also own the exact mixer you bought and needed some reverb. What I did is to route the mics to the mixer and the output of the mixer to the mic input of the keyboard. Then I have all the great effects inside the keyboard to use. The output of the keyboard then is routed directly to the logitech Z2200 speakers. Actually UD gave this idea a while ago. It really worked well !