Hello everyone!as you all can see that i am new!...lolz!Anyway i have two(2)all glass long aquariums -1 30gall&1 55gall.I want to start my very first reef(mixed corals) with fish tank,and will be using my 55gall as the main display and use my 30gall as a sump/refugium(using the Eco System Miracle Mud Method)with the exclusion of a protein skimmer.My question is this-i intend to which is better to use'live rock'of ''bio balls'' in the sump?