Digital Audio Interface Inputs Always Hot

I'm running a Berhinger UMC1820 on a 2012 Mac Mini with QLab 4.2.4. After trying to get QLab to control the volume of my mics (which it does down to a certain level) I adjusted the physical gain on the interface to bring the mic levels down to a not awful level for a "mic off" situation in QLab. In chatting with luckydave at QLab we isolated it to not QLab. And in rooting around with Apple's Midi Setup I haven't been able to use inputs as an aggregate device like you can for outputs to isolate different line outs on the UMC1820.

Anybody got any clues as to how I can achieve a total mute on my mics, physical mute buttons/hardware aside? Is it even possible?

Figured it out. My physical gains on the Berhinger needed to be all the way down.