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)

  • Saltwater Fish Boy..yes…dead rock and easily become live again.

  • Herrera…I use dead sand as well.

  • Saltwater fish boy says:

    I have a ? I live really close to the beach in hawaii. I can get ulva macro algae easy, but it’s wild and I see so many critters in there. I do not know if they are beneficial or bad. Im sure there are both. I can pick snails to eat everything. I am planning to put the algae inside of my refugium. Should I put it in my refugium? you have been a big help.

  • Syed says:

    Got it,Mark.very nice n clear.I thought I missed that vid earlier.thanks alot bro.
    No more questions for now.hv a nice day.

  • Saltwater fish boy…living in Hawaii?! I’m jealous!

    Since you don’t know what you are getting if you got wild caught ulva, I’d buy some from a good retailer like these guys. These guys are right in your state and probably sell it as well.

    While the algae will be in your sump, getting a pest into your tank could cause real headaches and could take a lot of effort to get out. It’s not worth the risk.

  • Cody D. says:

    I am buying a 75gallon reef tank from a friend(he is moving outta state and cant take it with him). Long story short I am new to saltwater aquariums… and this tank is easily 2 yrs old and looks great, however he only has roughly 60lb of live rock in it atm, and I would like to really add to it to make it closer to 75lb and maybe more in a refugium since it seems like he has a lot of open space for such few fish and such few space for soo many corals…I have been reading alot of literature, and obviously dead rock can become live rock, and I would really like to approach putting dead rock in the existing tank and biofiliter as opposed to live. My question is will this really yield the results I’m looking for and is there anything special I need to take into consideration when placing dead rock into a existing aquarium and biofilter?

  • Omar Morsy says:

    Hey Mark

    Wanted to ask you how you seed ur dead rock,The point of putting in deadrock is to avoid any parasites, so seeding ur tank with a live rock from a petshop seems unwise.

    So how do u seed urs?

    Thanx buddy

    Omar

  • Omar Morsy says:

    sorry u already answered that question.
    my bad 🙁

  • Omar…with this stuff

  • Naeem says:

    Hello Mark,

    I was watching the live stuff in your reef tank video.
    My question relates to your pink spot goby, you state that this fish turns over your sand bed, is this a sand sifting sleeper goby, i wish to add one but could not find any information relating to this fish sifting sand, i would prefer a sand sifter goby.
    Your help is appreciated.

    Kindest Regards.
    Naeem

  • John Pancoast says:

    Hi Mark Im addicted to your website and love the show I have learned more in the past couple weeks from your site. Im planning on doing a 30 gallon tank and im going all dead rock and sand. I have seen people say not to add inverts for 8 to 10 weeks I was wondering if you think the same and before i forget im also doing the one and only with the drops due to my LFS wants me to cycle my tank with 5 or so damsels and dont want to put the fish in a stressful home. Thanks

  • John…glad you didn’t take your LFS’ advice on the damsels! Smart move!

    Once your tank is cycled (probably a matter of days with the One and Only), then wait for your diatom bloom to show up. Then add in some snails and a couple of hermits. Then as you add in more fish, add in more inverts (clean up crew mainly). Adding shrimp once your tank is cycled is fine.

  • Trent S. says:

    Hey Mark,

    I’m about to buy my dead rock from Bulk Reef Supply for my 29 gallon tank. Do I still need to buy 1 pound per gallon or can I get a little less? I hear that when you get thirty pounds of dead rock you will get a lot more rock than when you get thirty pounds of live rock (I guess cause of water weight). Thanks for all the help and info, I know you must stay busy but your videos and info really help.
    Trent

  • Trent…I’d buy a little more than you need. You can always use it for rubble or gluing frags. Its easier to take out rock than add it.

    Don’t forget this stuff to cycle your tank

  • matt says:

    where do i get dead rock I need about 20 to 30 pounds for a 60 gallon cube

  • Robert says:

    Hey Mark:

    Loving your site aound videos… I am committing myself to researching salt water tanks for to bat least a couple of month prior to making a jump into the hobby. I notice your thoughts on dead rock and dead sand. My question to you is do I have to add small amounts of live rock and sand bring life to the dead rocks and sand? If so how much? If not what do I do to speed the life back into the dead rock and sand?

    Thanks for you assistance

  • Robert…use this stuff: mrsaltwatertank.com/4OAonly. It will get everything up and running in days.

    Adding is LR to “seed” the dead rock/sand is defeating the purpose. We want to start with a sterile environment so that we know we have no pests.

  • reefahholic says:

    Mark, quick question…I’m going to take the advice of yourself and BRS and buy some dead rock. How will I know that the LR that I seed the dead rock with will be pest free? Also, How long will it take to see some purple coraline algae grow? I plan on using the bottled 5/day cycle stuff from your buddy in California. Ohh, and where do I get this pest free LR to seed the dead rock and how much do you need to seed it?

  • reefahholic…there is no way to make the LR 100% pest free. If you seed your DR with LR, you are running the risk of introducing pests. Since you are going to dose the tank with Dr. Tim’s, there is no reason to use live rock to seed the tank. Just take the dead rock you are getting from BRS, dose the Dr. Tim’s and you are set.

  • Richard says:

    I’m also setting up a 29 gal tank and have ordered the dry rock and sand, plus I ordered the one and only. I was reading your comment on seeding it but the link you put in is a dead link.Could you please elaborate.I know that you have to seed for coralline algae to start growing in your tank.

  • Senecha says:

    Where can I get dead rock from? Would that be the same as base rock? I am sure this is a stupid question but must make sure. Thanks for all you do, it is helpful and appreciated!

  • Richard says:

    Hey Senecha I got mine from “Bulk Reef Supply” its called “Eco Rox”.

  • Senecha says:

    Hey Richard, thank you for the insight, I appreciate it. I am just starting to get things together to set up my 75 gal to begin the cycling process.
    Thanks again

  • Mark says:

    How much dead rock can you add to a tank that has been running for about 5 months?

    he tank is a 40 breeder and I have about 30 pounds of rock in the tank now, would like to add about another 40 pounds. Can I add it all at once or a little at a time?

  • Bart Greenland says:

    I am new to the world of salt water aqariums, but I am very fasinated with this new lifestyle.. I dont know that I am going about things proper or not.. All of my corals that I have introduced into my tank are doing well except one. I believe it is called a metalic green polyp. It is losing color. what are some if the things I can do or look at doing to get its color back.. I had this polyp glued to a rock and then pulled it off that rock and put it on another this is the time when I noticed its clor loss. do you think I could have hurt this little animal.. any advice would be helpful thank you

  • Bart…what type of coral is it? LPS? Soft Coral? SPS? “Green polyped” doesn’t give me enough info to help you just yet!

  • Dedric says:

    Hi everyone I’m a newbie. Help!! Here is my plan. I want to convert my 38 gallon fresh water tank into a fish only salt water tank (38 gallons). I’m going with dead or dry rock ( 30lbs) and a artificial coral reef because I really don’t want any ugly surprises (worms, bubble algae etc). I will add my bacteria from a bottle, not sure with brand yet but is seems like the safest route to avoid hitchhikers. Where I think I’m really getting lost is with the filtration. I debating between the Rapids Pro Series Wet/Dry Filter Systems with is suppose to be a wet/dry, canster and skimmer all in one or the Reaction 4 Stage Canister Filters with UV light and a skimmer. Any suggestion other than going with live (surprise rock) would be greatly appreciated.

  • dallas ballard says:

    Why are you against hang on overflo’s?

  • dallas ballard says:

    Thank you Mark you have helped me a lot. I have a 90 gallon already drilled and I have the same coralife hood you do bought all of it used for $250 but one of the ballast were bad still need to buy sump any sugestions I have coralife 220 skimmer!

  • bob says:

    i have a 500 gallon tank with 10 fish is this to much

  • bob says:

    i have a 250 gallon since there is so much water is it ok to pee in it once a week

  • Sam Reynolds says:

    Hi Mark,

    I have been watching all of your videos for a while now and think they’re great!

    My question is, with dead rock how do you get copepods an ampipods in your aquarium? Do you buy them in a bottle like some suppliers are selling or do they just arrive naturally?

    Regards and keep up the great work,

    Sam

  • Sam…I do what you outlined and spike the tank with those.

  • antoni Eishoei says:

    whats the name of the product i can use to bring my dead rock to life? and whats you take on using that so called live sand that comes in a bag?

  • antoni eishoei says:

    So dr. Time product will bring my dead rock and sand alive? I just want to be clear

  • Mark K. says:

    Have plenty of dead rock. When it was in my previous tank, four years ago, I had a valonia problem. Will the spores sill be alive even though the rock has been bleached in the sun?

  • zam says:

    i’m about to start my first saltwater aquarium.. my house is near the sea so i took the water from the sea and also sand.. before i start, i want to ask many people how to start my 1st aquarium.. my aquarium is 10 gallon.. if all the items are taken straightly from the sea do i have to wait for it to cycle like people always do??? do i need to buy any beneficial bacteria if i already have life rock n how long is the waiting period for me to add my 1st clownfish and coral? i also have skimmer and how much watt of light i need to put corals in my small tank??

  • Mason Howell says:

    Hey Mark, I just got a refugium to control my algae in my reef tank what kind of algae should i put in it to keep algae out of my display tank?

  • chaetomorpha algae is always a safe bet Mason.

  • Brian G says:

    Mark, Great site and love the TV videos, very informative and I am hoping you open your guide special again as I would be interested in purchasing one or all of your guides. My question is what you would suggest for setup if the only room I can place a reef tank is in our family room on the same wall as our television entertainment system? I am concerned with too much light and noise distracting the family TV viewing. Let me know your thoughts if you have any on this subject of tank placement.

  • kendra says:

    Hello we are new to salt water tanks and we have so many questions and not getting very many answers! First our take is over ran with algae we clean it all the time and the skimmer is always on we have snails and shrimp what can we do? second we had fish and they got ick all of them died and we lowered the salinity and warmed the tank *thats what they told us to do* but there never told us how long or where to go from there! we are at a loss! can you help?? we are losing lots of money due to this tank but we love it and want it to thrive!

  • Pamela says:

    Hello Mark, I have really been enjoying your videos. I am new to this site and will be buying my first saltwater tank from a person who is moving out of state and can’t take it with. I am excited about taking up this new hobby and want to make sure I do things right so I will be glued to your site and probably asking a lot of questions (sorry). My first question is: When we move the tank, fish and coral from one home to the other, how do we do this without hurting any of the life?

  • Josh says:

    HelloI am are new to salt water tanks and we have so many questions and not getting very many answers! First our take is over ran with algae we clean it all the time and the skimmer is always on we have snails and shrimp what can we do? second we had fish and they got ick all of them died and we lowered the salinity and warmed the tank *thats what they told us to do* but there never told us how long or where to go from there! we are at a loss! can you help?? we are losing lots of money due to this tank but we love it and want it to thrive!

  • Gino says:

    will dead rock cycle the tank by itself or do you have to add something to it to get the cycling going?

  • Steven says:

    I’m getting ready to start a 150 gallon reef tank. (Entusiast) I’ve read that soaking live rock in a hypertonic solution of saltwater (1.03 specific gravity) for 15 minutes can get rid of unwanted passengers and pathogens. What do you think or do you still recommend starting dead?

  • Andre Bertheola says:

    Mark, I bought an old 150 Gallon DAS aquarium.
    The Owner has bee using it as fresh water for 10 years in his bhack yard in large bins he has 100+ pounds of what used to be Live rock and coral it has bee sitting in this bin for 10 years. he also has about 50lbs that he used in his fresh water tank and took out a week ago some has green algae from the fresh water. I I am a bit of a noob. I have successfully maintained a 12g JBJ for 8 months with no death what so ever. and no bad algae outbrakes.

    My question is can i use this 10 year old dead live rock?
    it would definetly save me a lot of money to use it.

    But i dont know how or where to start with it.
    I read that since its been sitting out of the water for 10years all i have to do is brush it hose it down let it dry then put it in my tank or a separate bin and seed it with live rock bought from LFS for about 3 weeks and I should be good.

    I would like to hear your advice.
    Thank you.

  • Fish AL says:

    Years ago my then girlfreind and i went to Miami and i pluck a crap loud of coral of different sizes and shape right out of the Atlantic Ocean. I need cash in a hurry. How would I go about selling this stuff and would anybody but this stuff. ???????

Comments are closed.