Sorry kaserpick but I believe that to be untrue, live rock only acts as a filter when there is water flowing through it at an idea rate for the bacteria living inside of it to filter the water. The flow in a tank is not enough to push water in and out of all the holes at the correct rate, instead the way it works is the little creatures like worms and whatnot pushing the water in and out.... but the little creatures wouldn't survive in the back of a all in one tank in the dark.... or even not in the dark!