I have recently removed my bio balls and changed over to a new filter system. In doing all this I realized a large amount of silt in the bottom of my sump is this something I should remove or leave. I don't want to take it out if it's adding nutrients and such. But my nitrates were high and after water changes and losing tons of stuff in my tank I needed to make some serious changes. So again my question is do I leave the silt or take it out of my sump.