Jay,
I notice that no one is responing to your post. I must admit that I don't know everything but here I go. IMO the answer is No. I started my tank as a fish only tank with no LR. then decided to try a reef. I just added live rock to the existing lace rock I already had. I have seen no ill effects from having lace rock and my tank has been up for about 1 year now. As a matter of face the I think all of my lace rock has now became live rock. :wink: Some people don't like the lace because it isn't real live rock but for the money I for one don't see the draw back as long as you but enought LR to do the dirty work. Lace rock can be used as a good filler to avoid the high $$$ of LR.