i've got some that I've acquired in a rock buy from a fellow reefer--it's ok; personnally, I like the regular live rock. The homemade stuff doesn't seem to be as pourous, less little holes and crevices, corraline takes forever to spread (and I don't know why that is), just that kinda thing--one advantage-you can make your rock as big/small as you want and in the shape you want too.