How to Cure Live Rock

Note: All live rock should only be handled while wearing gloves.  There are many animals that can be hiding in and on the live rock that can cause a lot of harm to the person handling it. Animals such as Sea urchins, some snails and Zoanthids can be toxic to the touch, mantis or pistol shrimp can slash a finger down to the bone and open wounds can easily become infected from contact with the live rock

How do you cure live rock?
Ideally, live rock should be cured in a vast container that has a large volume of water in comparison to the amount of rock being cured.  This is to keep the ammonia and nitrites to an absolute minimum so that the remaining living flora and fauna isn't harmed. This point can not be emphasized enough because any raised levels of ammonia will kill life in and on the rock and could cause the loss of some species altogether.  The better the set up you have for curing the live rock, the happier you will be with the final cured pieces.

Equipment required:

  • Rubber Gloves - Please read Note at top.

  • Large food grade plastic container - the bigger the better. Two of them would be ideal one for curing rock, and one to store clean saltwater for water changes.

  • Heater - two would be ideal one for the vat and one for the clean saltwater to preheat it before doing water changes.

  • Power heads - two or three to ensure good water movement around the rocks

  • Test kits - Ammonia, nitrite and nitrate

  • Scrub Brush

  • Protein Skimmer - optional but preferred, will cut down on required water changes.

Preparation:
Before you bring the uncured rock home it's best if you set up the curing station to minimize the amount of work you need to do on the day that you get the rock.  This will ensure that the rock is out of water as little as possible and that you aren't overwhelmed with the process and forget some things.

Mix up enough saltwater as will be required to fill the curing vat. This should be mixed to the same salinity as the tank the rock will be going in once it's cured.  Don't worry about mixing too much water as you will need a steady supply of it for water changes throughout the curing process. Fill the curing vat about half full  and heat the water to the correct temperature.

The Process:

  1. Carefully inspect all pieces of live rock for sponge mater and material that is already decaying, soft or turning brown or black. Remove as much of the material as possible as it will quickly die off and pollute the water more then necessary.  Sponges will die if/when they come into contact with air and even if you kept the rocks completely submerged between the LFS and your house, there is no way to guarantee that it was submerged throughout it's entire trip from the ocean to the LFS.  Even if you would like to have sponges on the rock in your tank, enough of the matter will be buried in the rock that it should come back given enough time in your tank.

  2. Rinse the rocks off in freshly mixed saltwater and shake vigorously before adding to the vat to remove as much debris as possible.

  3. Place the cleaned live rock into the curing vat and then fill it with preheated saltwater ensuring that all the rock is covered. 

  4. Once all the rock is in the curing vat, position the powerheads in amongst the live rock to get the best water flow as you can. 

  5. If you have one, set up the protein skimmer at this time as well.  It wont immediately pull anything from the water so it will need to be adjusted throughout the curing process.

  6. If you have room to add more water then it is best you do since the extra water will help dilute the pollutants in the curing vat.

Daily Maintenance:

  1. Check on the live rock for additional decay.  If you notice large patches of brown, black or otherwise decaying matter it needs to be removed as quickly as possible. 

  2. Test the water for ammonia, nitrite and nitrates.  If the ammonia or nitrite levels get anywhere close to 1ppm a massive water will be needed with freshly made water that matches the salinity and temperature as the water in the vat.

  3. Even if the ammonia nitrite and nitrate level readings are not high a partial water change is needed to remove as much of the mulm that will accumulate at the bottom of the vat as possible.

  4. Reposition the power heads to ensure water flow all around the rocks with no prolonged dead spots.

  5. Adjust protein skimmer to ensure that it is skimming properly.

The length of the process will vary according to the type of rock you have as well as the amount of material on it that dies off in the process.  You will know when the rock is cured when the ammonia levels rise then fall and then nitrite levels rise and fall. 

Once the rock is cured it's safe to slowly start adding it to your tank.  If you cured a large amount of rock and are going to add it to an established tank with any animals in it, it's best to add it a few pieces at a time every 3 or 4 days while keeping a close eye on the water parameters in the tank and an watch how the animals react