I don't know for sure but copper pipes might hurt the live rock, but I don't know because I used PVC on my tank. Did you but the R/O from a fish store? If you did call them and see if they know if it will hurt the LR. I used to have a FOWLR tank but now I'm all reef. I know it will hurt some if not all reefs, I did use copper pipes on my R/O for my reef and it killed several corals.