The media for these tanks is Centaur Carbon. If it is the newer style with a center opening tank then you simply need to dump out old media, add gravel bed and appropriate amount of centaur (1 1/2 cu ft for 10x54 tank), being careful to not get anything down the distributor tube/manifold. If its the old style tank it would need to rebed by the dealer.
RJH2O
RJH2O