Suspended Particles

As usual I have a question,

My plant tank substrate is composed of natural dirt and rocks (fresh off the 
mountain).   I'm having a problem with tiny suspended dirt particles 
drifting around and landing on my plants.  Besides being unsightly I don't 
think it helps the plants out.  Any suggestions on how to get rid of it.  I 
have a large Aqua-Clear as the filter.  I jammed some filter-floss infront 
of the pump so it would suck up some of the dirt instead of clogging the 

Any ideas?