I used to have lots of live rock crammed in my sump.  After my last major sump cleaning I left all the rock out.  I much prefer a nice clean sump now with no live rock.  Instead, I float dish washing pads in my sump for extra filtration.   They are much easier to manage and cleaner.
And unlike live rock they also add a nice splash (pun intended) of colour to the sump. 
