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

[Reef Pilot]

I think it depends on what type of corals. I have mushrooms on my lower levels, and no question they trap nutrients. That is very evident when I blow around them with my turkey baster. However, doesn't seem to affect my P04 or N03 levels. They are still consistently near zero. So I think any nutrients that do escape the trap are quickly exported by the skimmer, GFO and bio pellet reactor.