My understanding is any nutrients trapped in coral covered rock will over time be absorbed by the coral(s) on the rock if anything I think it's the nutrients trapped under the rock or in pockets created below the rock that are disturbed that can lead to imbalance

But that's my opinion with nothing to support it ....

Having dismantled tanks and seeing these "pockets", I'd tend to agree. I think a design that allows free flow through and under rock is key in avoiding long term issues.
I do think that as a reef grows, you could remove rock as coral mass becomes bigger, with the corals now acting as nutrient export. This is of course very simplified, but I think a sound idea.

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.

covered live rock
 

Hi,

I have a lot of exposed rock with lots of nooks and crannies and not so much coral. The tank looks great but I need to use Instant Ocean's Nitrate Reducer to keep the algae in check and it does a very good job.

Just saying. I think your tank is georgious!

AquaAddict

I find it surprising that nobody mentions the coral's nutrient uptake. Corals (andby that I mean zoas too) use up nitrates and phosphates to grow. So, if anything, they help the nutrient equation. Sure, there's less exposed rock to harbour bacteria, but one can add rock elsewhere in the system: a refugium, cryptic rock in sump, etc. There's also tons of bacteria in the sand. Why would you want exposed rock in your DT?

I vote for coral-encrusted rocks over bare rock any day....

Pretty sure that was one of my first points :)

Ooops; I guess I should've read the whole thing.

so wait now lol you mean i can use corals and no need for rock then?

I read a journal on RC, guy was pretty much doing that!!

edit: This guy. Forget how much rock, but very little

http://www.reefcentral.com/forums/sh...5&pagenumber=1

i can believe it i have about 20 lbs in a 300g total system for zoanthids :)

i know of a supplier who keeps over 2500 fish (haw too so expensive) with about 50lbs of rock;)

it comes to knowing how your system operates:)