Not too many. I've tried to simplify things a bit. I've moved a lot of rocks to the sump, less in the display. I ditched the PVC structural suppor to for the rockwork. I've only kept rocks with corals, and even through some rocks with zoas into the refugium. I've eliminated my frag tank, and hospital tank as permanent fixtures. I've added an electronic solenoid for RODI system, so it'll turn on and off automatically. I'm no longer gravity feeding the skimmer, but I have routed a bit of flow from the drains to the refugium to help process the overflow that is too much for the skimmer (skimmer handles up to 800glph). Because i've cut my rockwork in half and am no longer 360 degree viewable it looks like i've added coral. I had zero coral deaths to this point but did create a lot of new frags due to clumsy handling.