After being out and free for about 10 years the hobby pulled me back in. In the last month or so I set up a Redsea 400 with this rock. I must say that it was the greatest purchase I've done in the hobby for a longgg time. I love all the hitchhikers, even Manthis shrimp. Most of the small sponges are slowly withering away, but they will continue to provide color for at least a few more months. The porcelin crabs are awesome, the little sea urchins are growing, the feather dusters are everywhere. My favorite is some kind of decorator crab that has a yellow sponge growing on it's back. Tank cycled in days, don't know what else to say, but I wouldn't do another tank without it. Only complaint is the quantity of rock, its too much.