Hi all, I've recently started a 29-gal reef tank, well it will EVENTUALLY be a reef tank currently it is just live sand, live rock, and this awesome rock I found in my backyard. The rock is natural (meaning not some sort of cement or concrete thing) and is full of holes and crevices. I had it in a freshwater tank previously and now have it curing with the liverock. A friend of mine was at his LFS and mentioned this rock, they told him I should not have this rock in the tank as it could hurt the reef setup. I'm not sure what that means.... and I figure this rock would eventually have all the same algae and tiny creatures on it that the live rock has, so how would that hurt my tank? Any clues anyone?