Mine came with the system. I threw them out though..I just mainly wanted the sump part for the equipment and reef rubble. You can order it at any online location, or maybe your lfs
. As Morticus mentioned, make sure the reef rubble is completely submerged. This method works differently than the bio balls.
Also keep in mind that if you decide to use the bio balls and change your mind later to reef rock, you will need to remove them slowly.