live rock question

[photocoral]

I am trying to understand the best filtration system to use for a large tank. I was wondering if it is possible to use some type of porous rock in an aquarium that is mixed with live rock. If kept together for a few months would all of the rock become colinated with the "good bacteria" from the live rock?
Would one be able to do this rather than buying the 1-2 lbs/gallon live rock people talk about?

[saturn tech]

you could use "base rock" mixed in with you live rock. i used a 2:1 ratio of live rock to base rock, respectively. the base rock is considerably cheaper then live rock, use the base rock as a base for your nice and pretty live rock.

[Indermark]

I have base rock on bottom with live rock on top of it. I did this so there is a constant flow going under and above the rock. Its uncured rock and placing it directily on the sand may cover up crap that needs to come off, that wasn't removed by hand the first time.

Ryan