Is coral covered live rock still a viable filtration media, or a nutrient trap ?

[gregzz4]

I realise things all balance out in the ocean, and rocks get covered in corals, but how does it affect us reefers ?
No more bacteria ? Trapped PO4 ? No nitrogen activity ?

My tank is rather busy covering the rock right now

Sorry for the crappy pics ... my camera doesn't capture anything well when the whites are off