Yes it seems that theoretically it should be removing nitrates but there is always the dangerous possibility that it could be disturbed, I assume your not using any sort of mechanical filtration between your display and sump, a sock could catch most of that, my sump is bare and only has spots of detritus(mulm?) and it's been running for over three years, have never cleaned it out

Sent from my DROID RAZR using Tapatalk 2