Live rock is the calcium carbonate skeletons of long dead coral and other calcareous organisms. It is called live because it has many forms of micro and macroscopic ocean life on and inside of it. Live rock is frequently used to culture new saltwater aquariums with life such as coraline algae, varies macro algae, sponges, copepods, mysis shrimp and bacteria which will filter the aquarium.
There is also base rock which is cheaper than live rock and has no life on it to culture the new reef aquarium. It can used to build the bottom of the aquarium reef wall and will be cultured by the live rock that is put on top of it. Base rock is usually not as porous and will not provide the same bacterial filtration as the more porous live rock.
Live rock is main biological filter of a saltwater aquarium. The bacteria in it will break down the ammonia, nitrite, and nitrates in the aquarium. The rock can also be placed in the aquarium to provide a safe haven for fish and a base for coral to be placed. In placing live rock in the aquarium you are trying to replicate the natural look of a reef wall.
Live has been pulled out of the ocean and will have dying life on it due to the collection process. Curing applies to the process of conditioning or cycling the live rock for use in a saltwater aquarium. Cured live rock means that it has already been through the cycling process and ready for use.
If a reef tank is already set-up with corals and fish it is best to cure live rock in a separate aquarium or container. Putting live rock in an existing aquarium can cause the system to cycle again and possibly kill its inhabitants.
Use power heads and a heater in the system to cure live rock. Remember that it has life on it and you want to create an environment that can save as much as possible.
Do water changes to help the water quality. How many water changes depends on how much life died on the rock. Large amounts of live rock can take longer to cure and require more water changes than smaller amounts of live rock.
Test the water for ammonia, nitrite, and nitrates. If you test for anything, WAIT and continue the process.
While it’s curing look for crabs or anything else you may not want in your reef tank.
Once the water parameters test are good for a week or longer after any water change the live rock is ready for use.