I have a mixture of rock in my tank, part of it is lace rock, just allow it to cycle with the rest of the new set up first, lace rock makes good live rock in my opion, there are a few people who says that lace rock/lava rock leaches toxin, I have not seen this, if it was good enough for chiclids, its good enough for salt water, heck, some of the old tanks I have tore down even have pieces of old asphalt road way in them for reef material, know if that dosn't kill it all I don't think lace rock is a problem.