I'm very new to this and my tank got wet on the 23rd Jun, 2 months ago. I got all live rock from a local guy ($1 a piece) a bag of caribee live sand and bottled water and it was almost instant cycle. As for the hitchhikers there have been plenty. Some brioptis heaps of other growth especially sea lettuce atm, odd snails and flat worms. Things that come out at night that I have no idea what they are. Most have been addrssed but the rock and the biodiverity it brings to the tank cant , I believe , be replicated artificially... when I upgrade to a larger tank early next year it will be live rock again no question.