how to cure live rock

How to cure live rock

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Live rock is one of the most important things you will add to your saltwater aquarium. It serves as both the structural and filtration-al… (I never miss an opportunity to make up a new word) foundation of most saltwater aquarium systems. Live rock also provides an important source of biological interest and diversity? Don’t believe me? Just take a look–a close look–live rock is awesome. But if you add live rock to your aquarium improperly–you could be asking for trouble.

live rock image 3

What is live rock?

A healthy coral reef is teeming with life. Even the areas around the reef that are not colonized by proper corals have tons of other marine life living on their surfaces–bacteria, sponges, algae and of course…worms…

Live rock is the term used for those pieces of rock that have broken away from the main reef. This happens naturally from storms or waves–and these days, live rock is even aquacultured, meaning it is ‘grown’ like a crop and harvested specifically for our use.

Where does live rock come from?

I’m not sure if this is an official statement or just officially my observation and opinion at the time, but the most common live rock I see around here (Philadelphia area) is live rock from Fiji. Some of the aquacultured varieties are grown in the Gulf or Caribbean regions in and around the U.S., but the important thing, from my perspective, is that the live rock, which was teeming with life in the water, was packed up and shipped across the country or across the world to you–and that has the potential to cause problems.

live rock in hawaii

Why cure live rock?

During the transportation and handling of the live rock–many of the organisms will die. Some of them will slowly die…as in…rot away…and you don’t want that to happen in your aquarium. So we cure live rock, in order to allow the natural die-off, while also maximizing the amount of life you keep on the live rock–after all–that marine life is exactly why you paid such a handsome price for the rock in the first place.

How much live rock do you need?

Well, that’s the topic of another blog post you can find here.

How to remove unwanted pests from your live rock

I picked this tip of from Liveaquaria.com–but some of the most troubling pests that can hitchhike their way into your tank are mantis shrimp and other larger predatory invertebrates, like crabs, etc.

The method they provide to remove those pests from the live rock is to submerge the rock in a bucket of salt water. The rock has been out of water for some time–the inverts inside it are pretty spooked. If you are lucky, you may find that the pests will take that opportunity to dart out of their previous home to find refuge someplace else, hopefully, more consistently wet. That place you’ve provided is the bottom of the bucket.

Let me know if this method has worked for you.

How to cure live rock

Now the event you’ve all been waiting for–the secret to how to cure live rock: You put it in some salt water and wait :). Okay, it’s not quite that simple, but here’s the deal. You want to put the rock in an environment where it can be completely submerged in aquarium-quality water for a period of 2-4 weeks (you will use test kits to determine exactly when the rocks are ready).

how to cure live rock

Equipment list:

  1. Bucket, trash can or empty aquarium
  2. Heater
  3. Air pump with airline or powerhead
  4. Ammonia, Nitrite and Nitrate test kits

Heat the salt water in your container up to about 78-82 degrees Fahrenheit and place the rocks in. I prefer to use a glass aquarium because I want to look at the rock while it is curing, to identify anything that is dying, so it can be removed/scrubbed off. It’s harder to see things when you take the rock out of the water. Arrange the airline or powerhead to provide a nice flow of water over and through the rocks.

Test the water, periodically, to confirm an expected spike in ammonia, then a spike in nitrites followed by nitrates that are expected when dealing with decay in a tank without a sufficient biological filter. Perform a water change every week if you see the levels getting high–remember, you want to keep the good stuff alive–while allowing for the bad stuff to die. The more you care about your rock and the life on it–the more you should test and do water changes. The more you think…well…it’s a rock…the lazier you can afford to be because you don’t care.

Look for dying stuff on the rocks–and scrub that stuff off with a toothbrush (preferably not your own) and put the rock back in the water. Here’s a link to buy a new toothbrush so you don’t have to use yours ;).

You can pat yourself on the back for curing your live rock when you test the water two tests in a row (a couple days apart) and detect no ammonia and no nitrites. It is normal, healthy and good to detect nitrates.

This whole process should take about 2-3 weeks.

Do one final, rigorous inspection to make sure you don’t have anything pesty growing on the tanks that you’ll wish you hadn’t introduced and you’re ready to graduate your live rock

Comments

  1. Great article Al. I recently moved my 120 gal. reef aquarium to a 180 gal and I had everything timed out so when my new Fiji rock arrived it would have at least 2 weeks to cure in my new tank. Unfortunately, because of some shipping issues, I received my Fiji rock two weeks late. I went ahead and move the 120 to the 180 and did exactly what you recommended in this article. After two weeks my test all came out where they should be and I re-aquascaped my tank. My new rock was a delight and after 2 months all my corals and inverts are thriving.

    1. Author

      Dale, thanks for the comment and for confirming a similar experience. How do you have the rocks arranged–are they in any specific arrangement or pattern?

  2. Al, why can’t I use my own toothbrush lol. I have bought live rock in lots of different places and always follow closely your advice, except I do use a skimmer to try to lessen the ammonia spike and hopefully save some more critters. Have you read of the change of circumstances reguarding export from Fiji? Some of the best rock I’ve had came from there, I hope it continues to be available!

  3. Great article. I have a question though, I recently bought a second used aquarium that came with live rock. The lady was kind enough to put all the rock into a new garbage can for transport home. It smelled of fresh saltwater. Unfortunately when we unloaded the aquarium stand, it was totally trash and I am waiting for my husband to build me a new stand before setting the new tank up. So while we waited I put a power head in with the rock and put the cover on and left it in my garage. However, I live in FL and it’s August. I think the water temp it getting pretty warm, even covered in the garage. The water has a new smell to it, not stinky, but not that fresh sea water smell. Is it still alive or will I have to recure it? Will a filter help? What if the salinity is low? Due to evaporation I have had to add RO water to it a few times. Thanks so much for your input.

    1. Author

      Hi Karen, thanks for the questions. The rock would likely be able to tolerate some increase in temperature, but there is a chance that some of the living stuff on the rock did die. But I doubt it was a total loss. If so, you’d have a pretty foul smell (I think…). Do you have an ammonia test? Would be good to check for that. You want to be sure you’re not seeing high nitrates, nitrites or ammonia before putting it in your tank for real.

      Good to keep the water parameters tight, like you’re doing. Keep up the good work.

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