How long does it take approximatly till things start growing on the live rock? What should I expect to grow on them and what am i looking for? They have paches of colour at the moment (red or orange)
Depends..
I had a 29 with just a skimmer and light and hardly nothing grew (colors) om my rocks for 5 months..
In my 125 I dose KALKWASSER and I can barely see and bare rock anymore it's all covered with dark maroon and purple Coraline algae.
As for what to expect, just corline algae is Ideal, and maybe a few small sponges on the undersides..
You really don't want any hitchhickers..
Very few of them are good..
I always say, "if you didn't add it on purpose, kill it..."
You shouldint be seeing much except for coraline algae growth. most of the larger organisms die or fall off during shipping and the only living things that will survive are crustaceans. As long as you get a healthy growth of red and purple Coraline algae, the live rocks you got is good.
there are thousand's of things that could grow from first introduction to years later just keep your eye on the new organism's that appear and if not sure what they are post me a pic and i'll identify it for you.