With ceramic media you want spheres since the ceramic doesn't allow water to pass through it hence you need spheres so water can flow around it. With cubes the media could pack and block off most of the flow.
With plastic media like this where water can flow directly through the center of each piece, cubes would work best by allowing the media to pack and forcing water to flow through it rather than around it.
With plastic media like this where water can flow directly through the center of each piece, cubes would work best by allowing the media to pack and forcing water to flow through it rather than around it.
