The harvesting of live rock has contributed to the demise of the world's coral reefs; PM Reef Ceramic is a hand made product and does not harm the environment. Live Rock is popular because in addition to eliminating ammonia and nitrites it will also reduce nitrates. PM Reef Ceramic mimics live rock in this arena and is more effective because of the expert engineering involved to increase surface area along with the pore design. PM Reef Ceramic allows more space for additional beneficial bacteria to grow increasing the capacity to eliminate ammonia and nitrites and reduce nitrates. PM Reef Ceramic also addresses some negatives associated with the use of live rock. Live Rock comes complete with live and dead critters that can contaminate a fish tank. Live Rock is heavy and can displace water needed by aquarium inhabitants. You can be assured that PM Reef Ceramic is contaminate free and lighter than live rock. It can be sanitized and reused and is also a great home for welcome guests like Copepods.