marine safe rock?

[MuddyWaters]

I would proceed with caution. When I started Reef aquarium last year I put a base layer of Tufa rock (from LFS), then Live rock for remainder. I had horrible hair algae issues for months until I finally found a couple of websites that said these kind of issues are often caused by Tufa. In desperation I pulled whole system apart, threw out the tufa and replaces with proper live rock; haven't had any hair algae for months now. Not sure if it is caused by the chem makeup of the Tufa or just how porous and how much detritus it can hold. Your rocks, while not really Tufa, may also cause issues, especially if it is really porous; I would try a small amount at first.