Mr. Saltwater Tank

Buy it Dead, not alive


As I’ve been helping people setup their new tanks, I’ve been advising people to buy dead rock vs. live rock (LR) for their new setups. People have been asking me why I say “buy it dead” so I thought I’d put it out there for the general audience.

The simple answer is selection – you get to decide what critters you want in your tank and which ones you don’t. Live rock is great in that it comes covered with nitrifying bacteria -i.e. bacteria that converts ammonia (fish poop an pee) to nitrites and then to nitrates. However, it also comes with lots of stuff you might not see and you don’t get to decide if you want it or not. For example, a lot of members have gotten LR that has aptasia and even majanos anemone on it. Majanos can overrun a reef tank in literally days if not tended to quickly. Even if you remove the ones you see, there could be several more that you don’t see hidden in the LR that will eventually spawn new babies that will end up in your tank.

Then there are the bothersome creatures that you might not be able to see – zoa/montipora eating nudibranches, or even the feared Kraken worm that grow up to 4′ in length and eat corals for dinner. (Not kidding, here is a link to some pics of a guy who pulled one out of his tank). You won’t know these pests are in your tank until you start seeing corals disappear or bleaching which no reef keeper ever wants to see. These pests are even harder to get out because you can’t always see them as they are very small and some only come out at night. Or in the case of the Kraken worm, you have to tear apart your whole tank to get to them.

With dead rock, what you see is what you get – no critters, no pests. I advise people to buy the rock that’s been out in the sun for long enough that it’s bleach white. No chance of cling-ons except maybe the backyard ant (would die in your tank quickly). No nuisance algae/anemones/worms/freaky crawly things. On top of that, you get to watch your tank mature as the rock will change from white to brown/green/purple as beneficial bacteria and algae grow.

So “buy it dead” and avoid the headaches of tracking down nuisance pests in your tank.

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Comments for this article (252)

  • Marc says:

    Hi. I’ve been buying live rock from my local fish store. And some secon hand also. I’m keeping it in a salty heated container with flow in my garage. I will be useing it when I set up my tank after we move hose. Prob about 3 months time. Would I be better of drying it out and starting again with it. And scape my tank with the dry dead rock.

  • Marc…if you are 100% sure the rock is pest free, I’d keep it going in the container. Just make sure you having a powerhead and a skimmer in the container.

  • Marc says:

    Yeh the rock is clean and has no visable pests on it. Will keep it running then. Thanx for the helpfull input mark. Ps keep up the good work mate. Ur my marine guru lol.

  • NickW says:

    Hi Mark,

    Quick question, if one were to use this method of scaping with only dead live rock/ base rock that has no bacteria on.

    How would one successfully seed the dead rock with bacteria to become live again? Once agian avoiding the nuisance critters? and bad bacteria?

    Kind Regards

  • Paul says:

    Hi Mark
    Thanks for all the info and videos you post to internet. For somebody who is starting out in the saltwater tank world its a great help.

    My questing is kinda seconds NickW’s. 🙂
    I was giving a tank with like forty pounds of live rock, I couldnt set it up for about a year, it sat dry and contaminate free. So I don’t have to intentionally seed the dead rock? In time once tank is cycled and fish are living in it, will it become just like any other live rock?

    Thanks

  • Paul says:

    I should add to my previous question. My answer is previously answered kind of but the link is broken. All the links to the aquarium cyclying stuff are broken. What is the stuff. Wonder if I could use Colony.

    Thanks

  • Nick & Paul…you can seed the new rock with nitrifying bacteria. I use Dr. Tim’s Aquatics “One and Only Nitrifying Bacteria“. If the dead rock was once alive it will have plenty of dead organic material that will decompose and provide ammonia for the bacteria to grow.

    I covered cycling a tank in my “No-Nonsense Guide to Setting Up A Saltwater Tank Vol 1” if you wanted a full explanation.

  • Antoni E says:

    I left my rocks under the hot LA sun for a whole week. After that week was up I cycled them in my tank, and added bio life to reseed them with life. My question is after a whole week of being under the sun can the rocks still give off phosphates? My tank is about 2 months old, and I have a reading of .08ppm of phosphates when using the red sea test kit. Thank you

  • Melinda says:

    I really like your tank, it’s really neat. I’m planning on doing mine similar to yours, when I get my tank cycled and the ammonia levels drop. My water was cloudy the last time I commented. I put some better bacteria additive and the water really cleared up, cleaned up the sludge. I added some dead rock to help. The badnews one my clownfish died for thing were getting better. The ph stays at 8.2 the salinity stays in the normal range. Nitrates and Nitrites are at 0 for right now. You know alot about saltwater tanks. I’m still learnin. I keeped freshwater tanks over the years.

  • Melinda says:

    I watch your videos on youtube, they are really helpful.

  • sonya says:

    Sooo wish I had read this prior to setting up my newest tank…majanos are no joke the fastest spreading pest around! Total tear down required to remove them. And I paid big bucks for fancy schmansy Fiji rock……uuugh!!

  • SOnya…you can always kill the Fiji rock. You can restart it easily and you’ll still have the good looking rock.

  • sonya says:

    I was tokillld if I boil the rock it will explode. How would you best kill it? I am ready!!lol

  • I’ve never heard the exploding part, but take a small piece and try it out and let us know what happens! Make sure you film it!

    Just leave your rock out in the sun for a week or so. It’ll kill everything on it. Then soak in RODI water for a week, replacing the RODI water a couple of time to help pull out any phosphates.

  • sonya says:

    Rock is in a pot on the stove! Listen for the explosion! Lol

  • sonya says:

    No explosion….boooo. Now to soak for a week. Killed a few brittle stars in the process but it will be well worth it if I am majano free. Neved again will I waste money on live rpck!

  • Doug says:

    Careful with boiling rocks if you have any zoanthids on them they can release a toxin in the steam that can poison you. Better to take the time like Mark suggested and let it dry out.

    http://www.advancedaquarist.com/blog/palytoxin-the-worlds-second-deadliest-poison-possibly-available-at-your-lfs

  • sonya says:

    Good to know! I assure you I was standing back from the stove waiting for it to explode. If I ever need to do this again I will use the sideburner on the grill outside.

  • phillip says:

    my local store sells dead rock at 2.50 a lb, and with my limited research online, that seems to be an ok price. are there any other sites that will save me money, shipping costs and what-not or do i just buy locally.

  • Austin says:

    I actually stumbled upon using ” dead rock” when I moved from Mississippi back to Texas. I moved back in 2010 and about a month ago i found a bucket that had about thirty pounds of rock in it when cleaning the garage. When I opened it it smelled fishy lol. So I just set it on the back porch for a while the pulled out my 15 gallon nano tank recycled some live sand from my 150 and believe it or not in about three months the rocks actually look better than some in my display tank.

  • Phillip..that’s a good price. Just make sure the rock is good rock – very porous and isn’t full of phosphates.

  • Ed says:

    Mark,
    I was thinking about adding more rock to my landscape, my tank is over 1yr old. If I purchase BRS Fiji Dry Eco Aquarium Live Rock will it spike my levels? Should I place the rocks in RDI water for a week and replace the water a couple of times?

    Tanks,
    – Ed

  • Kevin says:

    hey Mark, so i just started a new 90 gal tank and just started to cycle it using live sand. Now i was planning on using dry rock from BRS, but is it fine if i put the dry rock in later, or should i have done it from the beginning?

  • The rock should be there at the start. The live sand also likely won’t get the job done alone. I’d recommend adding some bacteria.

  • chris brown says:

    hello there i have a few? and would like some help. i have live rock and live sand in my tank now that has been running for 3 months i moved and never got to set back up the tank. well now im ready and i dont know if i should just add salt to my tank and rum with what i have. the water is fresh in the tank now no salt for 3 m time. or should i emty the tank and get new sand and new rock and start fresh? i ha e time to tend to it now and would love to get it back up and running thanks hope you can help.

  • Blake says:

    hey mark where do you buy the reel reef rock from? Any particular website?

  • Chris says:

    How would you go about get Coraline Algae to grow on your rocks (i love the look) when using all dead rock? I’m guessing you’d have to seed it from live rock, but then you’d run the risks again (though less risk since less live rock)?

    I like this idea of dead rock. I might do the DIY rock with clam shells & portland cement.

  • Doug says:

    You only need a very small amount, it can come in on a snail or the base of a coral. If you want to seed it you can do what I’m planning on a 450g tank that I’ll be setting up in the fall. I plan on scraping off some Coraline from a small piece of rock from my current tank to seed the new one.

    I’m sure it will take a while to really catch on in such a large tank but nothing good happens fast in a reef tank!

    I’m sure others have great ideas too…

  • Chris…as others have mentioned coraline algae will come in on a coral frag plug. In time it will likely spread in your tank if you keep your tank in good shape.

    Remember that there is no guarantee that coraline algae will grow in your tank. I’ve seen tanks with perfect water parameters that never grow any coraline algae.

  • Shane says:

    Hi I have dead live rock out the back of the house been out there for about 6 to 8weeks would it be fine to put in my tank or should I put in a tank of its own

  • Doug says:

    What were the parameters of the tank it was in? If that tank had high NO3 and PO4 then it would leach back out of that rock, so you may want to do an acid wash then let it soak in a bucket and test for those and deal with it before you put it into an active tank.

  • Shane says:

    The tank it was in went to crap and was bleached so what should I do

  • Doug says:

    If it were me, I’d start soaking it in a trash barrel and test the water if it has high NO3 or PO4 deal with it before you put it in a tank, the rock can store those nutrients and release them later, so even with dry rock which I’ll be getting for a 450g system I’m building this fall I’m going to be soaking the rock to see what leaches out of it and deal with it before I put it in the system.

  • Shane says:

    Thanks so if I put it in fresh water or salt water

  • Shane…I’d leave it soaking in RODI water. That will help pull out any phosphates in the rock.

  • Shane says:

    I use NSW that’s filtered and everything

  • Cato says:

    Im about to set up my first saltwater tank 75g and i been reading for weeks about how to get it right. But i have a question, im following your guid here and starting only with dead rock. Is it around 2-3 months before the rocks get the bacteria it needs? And would it help to add some bacteria to help The cycle? The moste common one we got here is tetra marine safestart, dr tims is no where to be seen in my country

  • Steve says:

    Hey roflmao, I’m the one laughing at the fact that you post this critique in a topic that you won’t find in a typical google search about live rock, not to mention that your last sentence is incomprehensible. I have found much of Mark’s advice to be invaluable, especially when I was first setting up a reef aquarium, his tips have saved me the time and patience needed to wade through all the contradictory crappy information people like you have filled the reef forums with. I have used the “buy it dead” concept successfully and know that what I put in my tank is what I want in my tank because of it. Thanks, Mark. I also enjoyed your presentation at MACNA!

  • phuong vuong says:

    i had bristle worms in my tank. i just wonder if their a way to complete get rid of them

  • phuong…bristle worms aren’t bad…leave them be!

  • Lee says:

    Hi mark I bought some ocean rock from my aqurium shop can I turn this into live rock if so how I do have two large bit of live rock in the tank but the rest is just dead ocean rock

  • michelle says:

    Mark,
    My saltwater reef tank was a victim of hurricane sandy and although I managed to save some fish and corals by putting them in a temp tank at a friends house who had power the tank itself got completely gross from sitting for over a week without power. I plan to start fresh and started the process of killing my formally live rock since I decided there was probably too much bad in them and we had an insane outbreak of majanos prior to the storm as well. I read about bleaching and acid wash and I started the bleaching process today. I plan on doing a series of RODI rinses & a rinse with amquel and letting them sit out in the sun before putting them back in the tank which we will re-cycle with dr. tims stuff as per your recommendation & fresh live sand and RODI water. Is the acid wash something you think is helpful or overkill? A fish store guy told me today that the bleach was bad idea & I’d need to spend $700 on new live rick which I am not gonna do. Thanks!

  • Ghassan says:

    If I bleach dead rock, is it possible to become live again? If i use regular rock is it possible to become live by time?

  • Ghassan…absolutely live rock and become live again with the addition of bacteria, corals and other live rock. Of course make sure the live rock you add is free of pests.

  • Devon Schneidt says:

    Mark, Is there a good site to buy the dead rock from? And what type/style rock do you use?

  • Devon..I prefer these guys or Real Reef Rock if your local fish store carries it

  • Alan says:

    Hi there I have just purchased a nano reef for a reasonable price. I also got some live rock which is dead I don’t know how long it’s been out of the tank it was in for. Could I use this in my tank and how would I go about doing so. Any information would be much appreciated thanks.

  • Alan…you can use this rock that came out of your tank. i’d soak it in RODI water for a week, changing the water every day to help remove any organics or phosphates stuck in the rock.

  • Alan says:

    Thanks a lot I’m new to keeping marines and any information is a plus thanks.

  • steve says:

    Hi Mark, i am struggling to find any where in the uk that sells real reef rock. what would be a good substitute for this ? I am thinking of getting ocean rock, is this ok? Cheers Steve.

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