Would this be ill-advised?

Well, my LFS does not have very much interesting live rock, what they have is very dense, non porous and not very pretty. I did notice however that underneath all of their tanks on a shelf they have dry man-made rock for about $3 per lb.

This rock is very large and very open with many caves and such that would be great in my tank for the fish to hide and feel more safe.

What I was wondering is if it would be okay to add some of this dry man made rock directly to my DT with about 100 lbs live rock already in it. Would this cause any problems? Is it even possible to place uncured rock in a DT with fish, corals, and live rock?

 

As long as the man made rock has been cured in freshwater to remove any leaching chemicals which would effect pH, then it will be fine to be placed in your tank and will soon become 'live'.

 

if it is dry base rock, with no organic material on it. then it should not cause a cycle. just make sure it is clean and made with safe components.

 

Some of the components of man-made rock can be dangerous.....not in terms of Ammonia, in terms of pH spikes like Phil said. It is imperative to find out if it has been cured already.

 

Why not just get natural reef rock? Reefcleaners.org sells the natural stuff for cheaper than that, with free shipping over 30 pounds. You can add dry natural base to the tank with no worries.