Live rock has gained a great deal of popularity for its success in supporting marine life in an aquarium. It has joined the protein skimmer as a standard for marine systems. Live rock is dead coral that has small marine life attached to it. The rock is obtained directly from reefs. It can be used in a Fish Only or a Reef tank. There are two types to consider:
Uncured - less expensive, but not acclimated. A significant number
of organisms die off in transport, so it will be necessary to rinse the rock and remove dead material. The rock must then be cured through a process identical to cycling a tank. It can take several weeks and the smell will "cure" you from ever trying uncured rock again.
Cured - more expensive, acclimated by the supplier. Cured live rock is
ready to support fish immediately. It's well worth the extra investment.
When placing live rock, ensure it is adequately supported and that there is still room to reach in and clean the aquarium glass.
Live sand is reef sand that has been obtained directly from reefs.
Like live rock, it also contains beneficial organism. It is much more difficult to ensure these organisms survive in transport or are re-established by cycling. Gobies and hemit crabs will appreciate efforts to establish live sand.