I would recommend the use of some live rock and some regular rock. Use the 
regular rock as a base on which you  build up the live rock. You never know 
what you are going to get when you purchase live rock so don't be surprised 
if you find some unwanted critters ie. worms in the rock. I have had a reef 
tank for about a year now and am just starting to notice a large amount of 
small feather duster type. If i can be of any more help just ask, I am still 
learning myself.
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