<p>Black Lava Rock is a porous aquascaping stone that is widely used for planted as well as African Cichlid tanks. This lightweight stone can range from a dark black to reddish-brown coloration. The porosity makes it suitable for use as aquarium filtration as the tiny holes provide surface area for beneficial bacteria to colonize. </p> <p><em><strong>You will receive 13LB per order. Sizes cannot be mixed and matched at this time. </strong></em><br><br><em><strong>*Important Note:</strong> Smaller pieces may be slightly buoyant due to their high porosity. </em></p> <p>Check out the Skull Island themed aquascape we did using Black Lava Rock</p> <p><iframe width="560" height="315" src="https://www.youtube.com/embed/3YaEleVR1W8" frameborder="0" allowfullscreen=""></iframe></p>