I'm not even sure this falls under water chemistry or not, but I just figured I'd post it here.....I understand the point of live rock and the tank, but my question is how do some of these great tanks run with very little live rock?? I know some have it in there sump, but some do not! Do they use stuff like seachem matrix?? Bioballs? Or is that old rule of 1.5 lbs of rock per gallon an old myth now a days?? I am redoing my tank this weekend and just wanted thoughts/opinions on how much live rock is really needed and what are some other options?