I agree with Geoff here on Cooking the rock, I did some really nasty rock that was full of hair algae and just bad, Thats how I got it the people did not want it it was so bad. I cooked it for a few months did weekly water changes during that time and had good water flow. the rock is great now, nothing growning on it but coralline and some tube worms. It was in total darkness during this time. another thing to do is go to the BB forum and read up on cooking your rock. Great thread.
Here is the link to the cooking Thread.
http://www.thereeftank.com/forums/sh...ad.php?t=66551