Adding Live Rock - To Add Or Not To Add?

Hi all,

I have recently started my first reef aquarium and have been in it for 4 months. When I bought the tank, the guy at the LFS gave me the sand and rock with it. However, the rock was the dead rock and not live rock.

I have read that once algae starts to grow all over the dead rock, it is basically turning it into live rock at the moment? If not, I want to look at gradually removing that rock and adding live rock, but I don't know if that is a good idea...

Will it mess up my tank's cycle? Will everything have to start all over? Will fish and corals die?

Any help would be great!
Was the tank used? Did he give you sand from an established tank or new sand?
The rock you have now, as long as it is reef safe, should be fine and is already live if it has been cycled in your tank. I wouldn't remove it.
165 G is a huge tank. How much rock and sand do you have in there?
No, brand new tank with new sand and rocks and everything. The rock I have now is going green (brown algae dying off eventually) although my Mandarin fish is making one heck of a meal with it all!

To be honest, I never got a chance to weigh the rock and the sand, the guy just put it all in. If I had to guess though I would say maybe 33Kg of rock with a 1 inch (I think, I am a metric person) layer of sand.
Its live now. Bacteria and micro-/macro-organisms make rock and sand live. Most people actually use almost all dead rock and "seed" it with a piece of live rock to speed up the process. I would recommend leaving it.

As far as quantity, you should have at least 165 lbs (75 kilos) of rock, if not more.