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.

Browse the Store! Questions?

Comments for this article (252)

  • Jacque says:

    Hello Mark,

    i just received about 60lbs of dead live rock. I got it from a friend and it has been sitting in their garage about 6 months. I just started a 125 lbs salt water tank and have in it live sand 5 snails, 2 damsels, 1 crab and 1 angel fish. I am so new at this and really don’t know much about starting a salt water fish tank and want to know the best way to add this dead “live” rock it I can at all. I have had my water right for about 5 weeks now. Can you tell me exactly what I need to do please?! Thank you

  • Ed says:

    Mark,
    I am in the process of setting up my new 175 gal tank and I want to add live rock. I was thinking about getting the live rock from Live Aquaria
    “Real Reef” Eco Friendly Live Rock – Fully Cured. Did you ever get the live rock from them and how safe (meaning pest free) is their live rock? I think they suggest to dip the live rock in a high salinity RODI water first. Other option is Live rock from from LFS.

    thanks,
    Ed

  • Justin Ferratusco says:

    Mark,
    I bought your guide to start my first salt water tank recently. I followed your directions precisely. I used reef saver rock and the sand you recommended. I used Dr tims and added a clownfish for my first one. He did great for two and a half weeks. I woke up one morning and he was dead. I checked all my levels and they were fine. I bought nemo again and he lasted four hours. Took a water sample to lfs and found my nitrites were extremly high. My test kit was expired which is completely my fault but how do you recommend bringing them back down. Lfs said live rock would solve problem. What is your recommendation. Thanks
    Justin

  • Justin Ferratusco…large 50% of better water changes will bring your nitrite levels down. If the fish was fine for 2.5 weeks, then passed away, I wouldn’t suspect an ammonia or nitrite level to be the cause of death.

    Also…what test kit was your fish store using? I’ve used a lot of test kits and found some to be horribly inaccurate.

    Finally, live rock might have prevented the issue IF the live rock was fully cured. If the rock was uncured or partially cured, it would have caused more issues due to the rock curing in your tank. And…live sand is far from alive. I wouldn’t waste your money on it.

  • Justin Ferratusco says:

    Mark,
    The store did two tests. One with instant ocean quick start and the other with res sea max. Both had identical readings. I cured my rock before starting my tank. Being reef saver from brs it only took two weeks. I will do the water change but my question is if I used Dr tims why did my nitrite level get so high. And also if it takes a week or so for levels to stabalize will I have to add Dr tims again with my new fish

  • Justin Ferratusco..how did you cure your rock?

  • Justin Ferratusco…also what were the nitrate readings that were “extremely high”?

  • Justin Ferratusco says:

    Mark I put it in my tank and filled with salt water and ran my pump in there until the levels were all at 0. Ammonia was a little high at first but didn’t take long to go to 0. I kept the the rocks in saltwater for over a month even though the cure only took two weeks

  • Justin Ferratusco says:

    Three to four ppm

  • justin ferratusco says:

    Mark
    I finally got my nitrate level down but in the process I lost another fish. Once my levels stabilized I added a new fish. After four days I checked my levels again and my ammonia is up to .5. I put in some seachem prime to try to neutralize the ammonia. I was going to do a water change but wanted to ask your opinion first. I’m not understanding why I’m having such a hard time with this cycling process. Any help will be appreciated.
    Justin

  • justin ferratusco says:

    Mark I meant nitrite not nitrate in last post. Thanks.

  • Mike Fountain says:

    Hi Mark.

    I love your guide. It is always nice to learn from others experiences to dial in your own. I have put together a 120 gallon. Instead of dead rock, I am using 80 lbs of fully cycled live rock from a friends aquarium. When I brought it home, it spent 3 weeks in trash cans with salt water and power heads with no lighting. I examined it frequently and found no pests or problems.

    Should I still expect to see a significant Diatom Bloom?

    I really took my time and several months putting the tank together. It’s rimless with two MP40’s, two Randion G2’s, Apex Controller with probes and ALD, a Seaside Aquatics ES2 Skimmer (Rated to 300 gallons), a Tunze ATO, and two deluxe BRS reactors.

    To start the tank, I used a full bottle of Dr. Tim’s and added two clowns and a small anemone from my previous nano tank. For the first 48 hours I did not run the skimmer, but have turned it on now. I also am using reduced amounts of carbon and gfo. Is it O.K. to be running the Carbon and GFO? Should I add a small clean up crew now that the tank has been up and going for a week?

    When it becomes necessary, I’ll add Kalk + to the ATO water and eventually will plan to dose Mag and Calcium. Not sure if I’ll really need to dose Alk?

    Again, thank you so much for your time and guides. They have really, really helped to start out on the right footing to have and maintain a Mixed Reef Tank!

  • Mike…thanks for the feedback on the guide.

    To answer your questions, you’ll likely still see a diatom bloom. Just keep in mind it will pass in time so just let it do its thing.

    Running the GFO and carbon can’t hurt. I’d keep it going.

    Alk dosing will be dependent on the tank. If your tank doesn’t need it, no need to dose it!

  • Gary Downey says:

    Mark, I recently purchased a used 90 gal tank which I believe came with dead rock. I say I believe it was dead rock because the previous owner had shut down the tank for 6 months before I purchased everything. Meaning the tank sat for 6 months with all the pumps shut down and the rock just sitting in the stagnant water. Can I reuse this rock? Can I just put it back into a saltwater system? Should I set the rock in the sun, bleach it or even boil it before putting it into the tank? If I can use it will it come back to life? Sorry for so many questions but this is my first saltwater tank.

  • Bruce says:

    Mark,
    An aquaintance of mine was tearing down a tank and wanted to know if i wanted his liverock (hell ya) his tank was pretty bad looking . My question is how do i treat this rock (30 lbs.) still has some good algea on it, pulled a few bristle worms out of it and some small slimers, do dry this rock out ?

    Thanks in Advance

  • Andrew Carling says:

    My comment is more of a question.. I live down south of australia now, but used to live in the gulf of carpentaria, and my 6 foot tanks were simply stunning, I took from the sea that surrounded our Eylandt and was very careful with the corals, I only picked the already dead.. I bleached them to make sure, and then I saoked them in flowing water for a week.. then it came time to put together another tank, as always and including now, I get my water directly from the sea, as natural as can be, before I placed the corals in the tank I would have a bucket full of sea water and a bottle of food colouring in it.. would soak the coral for a day or 2, then take it out, let it fully dry then put it in the tank..none of the fish seemed to mind, and the colours were not over bright, eventually softening into a pale colour.. just thought I would share this, and see how many slaps to my wrsit I get for doing this.. really, the fish did not seem to mind at all..

  • pat george says:

    i have dead live rock. can i use just r/o water w/o salt to leach the bad stuff out? I had it in a reef tank for a few years . had a lot of growth on it before i let it dry out. thanks for your input.

  • Derek says:

    Can I use sea stack rock to for live rock. It is about 400 million years old and has been out of the water for about 12,000 years. It is actually limestone Breccia. I want to start a reef tank and eventually add a few fish and have always been intrigued by this rock.

  • Ronald says:

    Hi Mark,

    A short question from one of your dutch fans.
    I plan to cycle with dry rock and the use of dr Tim’s nitrifying bacteria.
    Do i need To cure dry rock before putting them in my brand New tank.
    If the answer is “yes” how?

    Thnx for you advice!

  • Marc says:

    I know hyposalinity (1.009 SG) will kill inverts. Will it hurt/kill other beneficial organisms in/on live rock/sand if the system needs to remain that way for 6-8 weeks?

  • john esposito says:

    Dear Mark

    I wanted to use live sand in my new tank but do not want critters or aiptasia is there an alternative for a sand base

    Thanks John

  • shrikant says:

    Hi I want to convart my live roks in dead rocks, and also know that after it combatted they can ptoduce ammonia and nitrates please adviceadvice thanks lot

  • Scott says:

    wow lots of good stuff here I have placed some dead rock into my tank, it went through the brown algae stage and now I have bright green and red growths on it, any idea what these may be?

  • Phyllis Mercer says:

    I have a 56 gallon tank and purchased white base rocks and had them for a few months in the tank no animals yet just curing the base rocks and now I see algae forming on the top of the rocks. I was leaving my light on all day and night for curing. Do I still do the same? and how do I get the purple algae that everyone is talking about?

  • Ryan says:

    When would you reccomend seeding the live rock? Im going to let it sit in a tub till all levels hit 0 then adding it to a new tank I am setting up. Should I seed it when sitting in the tub (if so should I not cover it?) or during the cycling of the tank, mabye after?

  • Michelle says:

    Hi Mark,

    I’m hoping you can help me, I’ve asked these questions on several reef forums with little response. …
    I’m going to try and cycle 100 lbs of dead rock in a large brute trash can and saltwater. The rock’s Been sitting in a bin in the garage for 2 years, so definitely dead. It has been rinsed out very well in ro water. Now for the ??, Can I put all of it in the same trash can with a powerhead or is that too much rock? Most is tonga branch, some Kaelini, and some Fiji. Most are medium pieces and some are smaller. All fit in the can with a lot of room to spare. Also, will it need a heater? and how often (if any) do I do water changes? How much should I change? I also have a couple pieces of cured rock to throw in. My goal is to have it cycled in about 6 weeks so I can add it to my tank when I move to my new home.

  • Chris Radici says:

    I am building my tank this Friday and need to set up my rock. I am inclined to go with Real Reef vs. Live Rock, however someone at my local fish store said that you cannot grow and maintain SPS coral with Real Reef. Once he switched to 50/50 and placed SPS on live rock, then he did not have an issue. Is this true? Have you heard that?

  • John Milgram says:

    Hi Mark, I love the way you have turned your enthusiasm for the hobby into a way to help so many people! That is inspiring!
    I have a 75 gallon tank that was fresh water and I turned it into a salt reef… I know I’m not doing it the best way but here’s what I’m doing: skimmer rated to 125 gallon that’s a hang on the tank model… canister filter with carbon I change every 3 weeks… uv filter in the tank… Two 1200 max jets running two under gravel filters. Two Kessel A350W lights.
    I’ve been using tap water but am switching to RO water. I have been adding a fish or coral a week since October. I have 20 bottles of different coral foods and calcium, iodine, buffers and alk supplements, strontium and magnesium. I feed the tank with fortified brine and sinking food for bottom dwellers. I have just bought my first LPS coral but I have zoos and other soft corals for a while.
    Any advice to keep things running smoothly. In this counter culture environment?

  • Paul Mason says:

    Hi mark, i have always kept freshwater fish, oscars dempseys etc, i have now decided to attempt salt water, so tank has been cleaned properly i have already made the mistake of adding live sand and base rock into the tank before i got my salinity levels correct, i am going to buy some live rock and dead rock tomorrow and add them to tank to begin cycle ( will the cycle begin with just live rock etc or do i need hardy fish aswell?, basically i am totally clueless and my main concern is filtration, i have a fluval 406 canister filter and ive read that they are no good for saltwater setups, is there a media i can replace fluval media with to make it better? i have bought a cheap hang on protein skimmer just as a temp measure as im struggling to find one that will fit my tank due to having glass braces inside so the intake etc of skimmer clashes with glass brace and wont fit my tank do you know any pretty cheap skimmers that are designed for tanks (U.K 175ltr) with braces?
    thanks very much… ive watched loads of videos on youtube including yours but so many people tell you different things and just confueses the newbies to the hobbie.

  • joe says:

    Mark……help me hear buddy.
    I work on a construction job site down here in Miami Florida. They’re digging 25’deep here and I’ve scored some beautiful coral rock down here and I think it’s reef saver rock I believe they call It. How the heck do I cure this thing? I put one piece in a vinegar and water solution and I put another piece in a claro water solution.

    The vinegar solution is bubbling and all kind of things are happening the color of solution. …….nothing.

  • John Butler says:

    do i need to cure dry rock before starting a new tank?

  • Walid says:

    Hi Mark
    I have just started my first sea water tank
    I have put some live rocks , didn’t know that I shouldn’t keep the light on for a lot of time . I just found that some of them is turning white
    I am now Putting the light on for only 2 hrs per day
    Do u suggest anything else ? Should I remove them or change them?
    Thanks

  • Michelle says:

    When adding dead rock to an aquarium do you have to soak it first rinse it how do I do this?

  • Liz says:

    I got 6 pieces of real coral ranging from 1kg to 5.5kg when I bought my tank, I don’t want it so where can I find a price of it’s worth so I can sell it.

  • Tom says:

    Mark, I think your article is misleading and misinformed.
    Yes real Live Rock does have critters on it however the good ones far outweigh the bad ones, and the story you speak of with Kraken worms, they can come from anything you put in your tank. By talking people out of using real live rock I believe that is working against the hobby. It is like a rite of passage to sit in the dark with a flashlight after receiving your live rock and see what comes out of the rocks, all the new critters.
    Yes some are bad, but most are great things you want in your tank and without having to deal with the bad ones you are losing out on valuable information that you can and will use later down the road.
    I have had many tanks and by far my favorite way to start them is real Live Live Rock. I feel scaring new people out of using Live Live Rock is not helping anyone, I believe that giving people the truth (not one guys horror stories) and letting them decide is far better.

  • Tom…the good critters can all be supplemented into the tank and a lot will come in on corals. People always have the right to choose what kind of rock they want to put in their tank and the point of this article is to provide an alternative view point from the “live rock only” approach.

  • dave says:

    I say if both take time to cure regardless then why not pick the rock that takes more time? If theres anything ive learned in this hobby is that patience is key. If “time” is the only thing your worried about then your in good shape because theres plenty of time. Why not just cure the dead rock yourself so you dont have to worry about the bad things and get to watch the good stuff work.

  • dave…some of the “bad things” can survive for months. Just because you are waiting things out doesn’t mean you are getting rid of issues that can arise with the rock

  • Sam says:

    Hey Mark….
    My interest in saltwater aquariums has grown over the past year..
    I know only what I’ve researched online and questions that I’ve had answered from my local aquarium stores..
    I’m lost!! It’s a science!!!!…, one I’m having a hard time figuring out!!
    I’ve started and maintained a 10gallon for 10 months. I started with nutri-sea water, 11lbs of live rock, and live sand. I have a aqua clear 30 a heater and a small t5 bulb suited for a 10 gallon. I have 2 clown fish an emerald crab and 1 hermit crab remaining and a single piece of a low maintenance coral. 3 snails and 2 hermits passed…, I guess no more algae caused the hermits death.. The only issues I’ve had we’re red Sinai algae and a few of those aptasias.. A syringe with calcium I believe handled my aptasias and a black out of around 4-5 days fixed my algae problem. So now I have the itch…, I want to go bigger…., but the info I’ve gathered varies so much, I don’t know which route to take. Please help!? Future plan 150-250 gallon, I’m most likely gonna go with fish only.!!! Here is where I hit a wall!
    At first I assumed what I did with my 10 gallon I would do with my future tank. Then I was told: no need for either live rock or live sand!!!!
    Just go with regular clearly dead fake or whatever bleached corals, dead sand and do a wet dry, with maybe a skimmer. So I guess my question is, what the hey do I do…??? If I go live rock and sand I guess I would only need filter socks a skimmer and carbon in my sump?

  • Chris Wiebler says:

    Well I wish I would have read this earlier. Ive had my tank for about a month now. Started with aptasia, got rid of them due to aptasia x. then the bad little starfish, only saw one. Now I saw a worm and one of the heads on my hammer coral got messed with last night. I don’t know if it was the worm or not. it was too small and went back into the rock for me to look closely. And my Pink birdsnest is pale and sick or something. And I put a lawnmower blenny in about 3 weeks ago and haven’t seen him since. Anyway, Im thinking about starting over, killing my rock, and sand. How should I go about doing this? or what do you suggest I do.

  • Jon says:

    May take longer for your to mature but well worth it. I still have a 3 foot Kraken Worm in my tank (luckily its a FOWLR) but man its one ugly worm. Seen it about 5 times in about a year (never bothers my fish thou)

  • Matthew says:

    That Kraken worm is frightening!…Thanks for the nightmares, lol…..So glad I used dead rock.

  • Sonny says:

    Hey mark been following your posts for awhile now and I was just wondering I’ve had some live rock (dead rock) outback in the weather for over a year and the bucket ended filling up with water and went all bad what is the best way of cleaning and curing it naturally not worried about how long it would take the tank ain’t up and running yet and would I have to seed it with some live rock thanks

  • Sonny…I’d soak it in RODI water. Every 3 days replace all the water and continuing soaking. Do this for a month then you can place it in saltwater, add some bacteria in a bottle and you’ll be off to the races

  • Sonny says:

    Thanks mate for the reply I will give it a go

  • Ahmad says:

    Mark
    Great site and info. ? Bought a used 120 gallon tank broken down for 6 months which came with live rock that is dry in the tank. I have it soaked in fresh water only. ? How long and what else do I need to do before setting up my tank with the rock. 110 pounds or so.

  • Ahmad…soaking the rock in RODI water is the way to go. Simply soaking it in tap won’t get the job done. I’d soak it for as long as you can…at least 2 weeks

  • Colby says:

    I have dead rock and was wondering will my tank start the notrogen cycle on its own with out any thing else like fish or do I need to add a damsel or somthing

  • John Ray says:

    Mark,
    I am reading some of these questions and it appears the ones i have are leaving me confused. I purchased an up and running 125 gal saltwater tank with live rock! I am a disabled vet and the day i took it down i went down for about a week. I had the rock in large rubbermaid trash bins. Well the nitrate and ammonia levels are thru the roof. I have to move them as my roomate has a show car he needs to put in the garage. From what i read i can take the rock out of the dead water and put them in the sun. Then when bleached introduce them to the aquarium with some live rock correct? I would rather not trash this much rock but trying to cycle it in the trash bins is not working.
    Thank you for your help in advance,
    John Ray

  • I have noticed you don’t monetize mrsaltwatertank.com, don’t waste your traffic, you can earn extra bucks every month with new monetization method.

    This is the best adsense alternative for any type of website (they approve all websites), for more details simply search in gooogle:
    murgrabia’s tools

Comments are closed.