Live rock rubble will also give you a few added benefits on top of Porosity. The ceramic beads all have set pore sizes. this means that typically only one type of bacteria, etc can live in that opening size. Liverock rubble has multiple pore sizes allowing diversity of bacteria. Another aspect is that Ceramic beads are typically a silica based ceramic, liverock rubble is calcium based. That fact alone would make me switch to rubble over beads
