Does everyone experience a build up of detritus on the live rock after the tank is up 5- 10 years? Am I supposed to be removing the rock and cleaning it, without removing or harming the living material on and in it? it has a layer of detritus that looks like a film of dust on furniture left in a room for years. 2 powerheads and 2 pump exits into tank, there is lots of movement? what am I missing? 72 gal/ mega flow 2 sump.