Yes it has an established bacteria population; the rock looks like "dead" rock but it has been stored in tanks culturing bacteria and they also use coraline algae spores. I can tell you they are awesome people to work with, extremely supportive, the tanks I used them in cycled quickly w/ OD live sand. I really think they are onto something and I'm quite happy with my experience...shoot them an email with any questions, that's what I did and they are extremely gracious and helpful ...I will use them in the future ...