Cleaning Tank/LR/Sand - Buying used tank

[ildknyli]

I am new to the hobby so please bare with me...I tried to search but didn't come up with anything that was clear.
I'm in the process of buying a 125 gallon tank from a friend. Its currently running and has fish, live rock and sand.
I will probably setup the tank starting from scratch, mixing the water instead of using his. The plan is to set up the tank as a reef tank...
I was wondering what is the best way to clean the live rock(they have a bunch of algae on them) and what kinda of precautions should I take after I clean them to the time my water cures?
If you have any additional tips for me please post.
Thanks!

 

[meowzer]

WELCOME TO SWF...and to sw keeping
What are you going to do with the fish while you get this set up?
What type of algae? I would use new sand, maybe just keep a cup or 2 of theirs to seed it with.

 

[ildknyli]

The fish he is going to keep in another tank of his as for the type of algae...im not sure. I can take a picture.
Can you give me reasoning on using new sand? Is it too much work to clean?