FAQ Purchasing Live Rock


Active Member
Having just purchased another 50 pounds of live rock, I wanted to share some of my experiences. I hope this answers some questions.What is live rock?
Live rock is not actually alive. The term comes from the fact that the rock is populated with many micro and macroscopic organisms from the ocean. Most live rock is not rock at all, but rather the skeletons of dead corals and other calcareous creatures. Live rock can be either cultivated from the wild or farmed. Cultivated rock is generally collected pieces of rock that have broken off naturally and settled at the bottom of the ocean. Farmed rock is "dead rock" that has been dumped into the ocean and recollected after it has become alive.
What are the different types of live rock?

First of all, there is "inshore rock" and "outshore rock." This just explains from how far out in the ocean the rock was gathered. Inshore rock tends to have more desireable growth on it.
Live rock is further categorized by the geographic location from where is was gathered. The differences that occur from region to region are weight, shape, porosity, type of macroalgae & critters and price. I have found that the shape of the live rock impacts it's pricing more than any other factor. Oddly-shaped pieces with interesting features usually demand more dollars per pound than bulky, featureless pieces.
Some regions where live rock is collected from are: Fiji, Uaniva, Vanuatu, Tonga, Bali, Pohnpei, Alor, Haiti, etc. Most live rock is gathered from the shores of 3rd world countries, islands, and countries with lax collection limitations, for obvious reasons.
What is cured live rock, and why is it more expensive?

When live rock is extracted from the ocean, the act of removal from the seawater is traumatic for some organisms. Shipping the rock is also detrimental to the organisms on the live rock as there is little to no water in the packaging. These and other factors lead to a condition called "die off."
Die off is when some of the micro and macro-organisms living on the rock perish. This is inevitable no matter what precautions are taken. Certain organisms such as sponges and seaweed are almost guaranteed to die during the transition from ocean to tank. The ones that survive do so because they are either hardy, retreat to the center of the rock, or they live within the rock itself.
The reason "cured" rock is more expensive than "uncured" rock is that the seller has already gone through the process of letting the live rock undergo the die off phase, thus eliminating much work for the buyer. Curing rock can take anywhere from one week up to a month, and takes a labor force to manually remove some portions of the decay. Most shipped, cured live rock will still require further curing by the buyer, but the amount of time spent doing this will be drastically lowered.
How much does live rock cost?

The price of live rock varies greatly from seller to seller. I have personally seen prices ranging anywhere from $1.50 per pound all the way up to $10 per pound (2005). This aspect of the hobby requires research on the buyers' part. While one seller may have very inexpensive live rock, he/she may charge exorbitant shipping fees, and vice versa.
The price of your liverock generally reflects onto the quality of the rock itself. Generally speaking, you get what you pay for. A good avenue for obtaining inexpensive live rock is the internet. Prices on the internet are generally very competative and tax free. Many internet sites also pay for shipping if you place a large enough order.
Local fish stores tend to be more expensive than the internet, especially when you figure in tax, but they have a couple of benefits over internet purchases. First of all in a local store you can personally inspect each piece before you buy it. This way you can be sure you are getting pieces with interesting shapes and good growths of coraline algae. Secondly, in a local store you can haggle for a better price. Many stores will give you very low rates if you buy in bulk, especially if you are a regular customer and have rapport with the staff.
Do your reasearch, visit internet forums, ask questions, and you should be able to match a good quality live rock with your budget.
Why do I need live rock?

Live rock acts as a giant filter in it's natural setting, the ocean. It contains the important bacteria that break down and process harmful chemicals realeased when creatures produce waste. The most toxic of these chemicals is ammonia, which is broken down into nitrites by one type of bacteria, and further down into nitrates by another type of bacteria.
Live rock is also populated by other organisms large enough to be seen by the

eye. Although most of these are nocturnal and only come out at night, they are there. These consist of worms, arthropods, echinoderms, mollusks, etc. Most of these creatures are detrivores, which means they feed on the wastes of other creatures. While the main functions of these organisms are to keep the tank clean and the water quality pure, they also serve as food sources for your tank inhabitants.
Live rock (and base/dead rock) also provides the framework for reef tanks. If you plan on having invertebrates such as corals, anemones, feather dusters, etc, then you will need rockwork.
Aside from a protein skimmer, live rock is probably the most efficient means of keeping the water in your tank clean and pure.
How much live rock do I need?

The general rule of thumb for a reef tank is one to two pounds of liverock per gallon. However, one has to take the density of the rock into consideration before using this guideline. Depending on where the rock came from and what it is comprised of, two rocks of identical size can be very different in weight.
The best method, if possible, is to view the live rock before you buy is so that you can pick an appropriate size and density for your tank. There is nothing more dissapointing than ordering a shipment of live rock, only to find that you have a few very heavy pieces that do little in giving your tank that full reef look.
Why is base rock cheaper than live rock? Can I use it instead?

Base rock is also referred to as dead rock. It is completely dried out and contains absolutely no living organisms. Because of this, the rock needs no special holding tanks or shipping considerations, so it is much less exspensive than live rock
Many people opt to use base rock to create the foundation for thier live rock. This is when one layer of base rock is put into the tank, and the rest of the structure is built using live rock. Other hobbyists choose to build the entire structure from base rock and place just one or two pieces of live rock on the top, and wait for the live material to spread to the dead rock.
Some aquarists have highly negative views on base rock, while others have very positive views. In an effort to maintain a neutral point of view in this article, I will only state proven facts on the subject rather than opinion or less documented facts. Base rock is cheaper than live rock by a large degree. Base rock takes a considerably longer time to grow macroalgae and coraline algae than live rock (the good stuff). Live rock has a chance to contain both beneficial and malignant hitchikers on it, much to the joy or dissapointment to the hobbyist. Base rock has no chance of containing either. Base rock contributes nothing to helping a tank cycle.
Can I put live rock into my tank during my cycle?

Both cured and uncured live rock are safe to put into your tank during its initial cycle. In fact, live rock can be used to help cycle the tank instead of using bacterial additives, a dead shrimp, or the outmoded tactic of adding damselfish. One word of caution though: if you put uncured rock into a tank during the initial cycle, it will stink. I have heard of varying degrees of stink ranging from a slight, unpleasant odor around the tank to having a smell so foul that not even the dog would enter the room.
Cured rock can be put into a cycling tank but this will more than likely result in more die off due to unstable water conditions. This die off will help cycle the tank but the problem arises in your pocketbook. There is no reason to buy precured live rock if you plan on cycling your tank with it. Save a few dollars per pound and buy the uncured rock.
I have heard that adding live rock during a cycle can speed up the process in the range of anywhere from one week to three weeks.


Active Member
How do I cure live rock? What do I need?
Curing live rock is relatively simple, but sometimes it takes a lot of patience. It can be made considerably more easy with the proper tools.
Below is a list of tools that you will need before purchasing your live rock.
  • Large plastic container (big enough to hold the rock and water.
  • Saltwater mix. (enough to fill the container)
  • Distilled or RO water (enough to fill container)
  • Stiff-bristled brush. The stiffer the better, but not metal bristles.
  • Clean toothbrush.
  • Screwdriver (phillips head is better)
    Plenty of towels
    Plastic tarp
    One powerhead of around 150 gph.
    Heater large enough to heat container volume.
    Measuring cup and stirring device
You will start by filling the plastic container about 1/2 to 3/4 full of purified water. Be sure to mix the correct amount of synthetic sea salt to this water. Use a large plastic spoon or something similar to stir the water until no traces of undisolved salt remain suspended. Set your heater to around 75 and place it into the container. At this point you can set up the powerhead if you wish, careful to place it at a level where it will not squirt water out of the container should some evaporation go unnoticed.
To clean your live rock you will need to set up a plastic tarp or shower curtain on the floor near your plastic container. This will be used as a surface on which to clean the live rock. You will need to clean your live rock as much as possible before it is put into your plastic tub. I recommend having all of this set up in the bathroom as spills are more than likely going to occur. The actual process of cleaning the live rock is very messy as well.
Your first step to cleaning your live rock is to manually pick off any debris that you can by hand. After removing the large pieces, you will need to use your stiff-bristled brush to scrub the rock. Do not be gentle; give the live rock the same degree of scrubbing as you would a stain on a carpet. Although small pieces may break off, this is to be expected. After you have used the brush to scrub the rock as best as you can, you will now use the toothbrush to scrub the hard to reach places and holes in the rock. Scrub with the same abrasiveness as you did with the large brush. Remember, this is a calcium-based rock, not a porcelain doll. Once you are done scrubbing you can rinse the rock off with purified water. Although I am sure you can use tap water for rinsing, I would be highly concerned that it would cause even more die off.
The next step is to remove the dead or dying things that you were unable to remove with scrubbing alone. This is where the screwdriver comes in. Use the screwdriver to dig out any roots or dead organisms that are difficult to remove. I have mainly found small, rounded, black bumps that fall into this category. Other parts that may require the use of the screwdriver are growths with blackened areas underneath them. Just pop the growth off and give the blackened area a vigorous scrubbing.
An important thing to keep in mind when cleaning your rocks is not to fall victim to the "this looks neat" syndrome. If anything is squishy, black, or soft, remove it. Do not think that leaving it on the rock will result in a nice addition to your tank. Anything squishy, soft, woody, including soft algae, has a very high chance (90% or so) of dying in your curing container and fouling the water. This will inevitably lead to more die off.
After all of your rocks are rinsed, scrubbed, picked clean, and rinsed again, you can add them to your plastic container. This is where patience is a virtue. The next step is to let the live rock sit in the plastic container for a week.
After a week, remove the live rock and inspect it. If it has no squishy, soft, or scummy parts, and smells like the ocean, then it is cured. If it has a foul smell (even slightly), then you will need to scrub it all down again, make a new batch of saltwater, and place the rock into the bucket for another week. This entire process almost never takes more than four weeks. You can test for ammonia to help see if your live rock is cured as well, but this is a sketchy assumption at best.
How do I add my live rock to the tank?

Once the live rock is cured (or if you are using uncured rock to cycle the tank), you need to think about how you are going to arrange it in the tank.
One very important step in placing the rock is creating a stable foundation. Whether you use base rock to create the foundation or not, the very bottom layer of rock MUST rest on the bare glass of the tank (or on commercial products such as plastic egg crate). This is done so that critters in your tank can not burrow underneath the foundation and compromise its integrity. This can lead to the rock crushing the critter or toppling over and breaking the tank. Once the foundation is laid, you can move the sand around the rock to fill in the space.
In placing the rest of the rocks, the largest and heaviest ones should go on the bottom, with the lighter ones on top. Following this basic rule should prevent most instances of unsteady rockwork. Try to place the rocks that are most aesthetically pleasing in positions where they are noticed, and use the featureless rocks to prop these up and act as support.
Make sure that you do not pack the rocks tightly in an attempt to duplicate masonry. This can lead to dead spots and algae blooms. Make as many caves, nooks, and crannies as you can, to both provide hiding spaces for your livestock, and to permit water to flow unhindered throughout the formation. The less solid the formation, the more effectively the live rock will be in filtering your water and keeping it pure of contaminants.
Try to place powerheads in positions where they direct currents across the surface of the live rock. You can even place powerheads behind the live rock so that they direct currents completely though the formation. Also keep in mind that the water level is going to rise as you add more and more live rock. Have a bucket or two on hand to deal with the extra water.
I hope this helps somebody.
Mark Werenczuk
ps- feel free to comment if I missed anything. I will update this if it needs it and I'm not feeling lazy.


Great material mud, I have a fish only tank with no live rock. It has been up for about 7 months. Never even thought about live rock until a few months ago from this site. I am getting ready to order some from this site and they say it is "pre-cured". I assume I can't just put it in my tank. But since it is "pre-cured" how much time does it need to cure before I put it in? Being pre-cured how much might it mess up my tank if I did put it in straight from the box? Thanks for the read and any help.


Very informative and helpful; although I have already gone through the process of obtaining my live rock I can easily see where this FAQ will be more than helpful to the new hobbyist or veteran with no LR experience.
Seeing how visuals play an important part in choosing live rock, perhaps you can add a paragraph or two (near where you described locations) where you describe the 3 or 4 more common types of live rock, their structures, benefits, and what sets them apart visually. This may be a bit more of a chore but I think it could add to the artical.
All in all a very good FAQ. Great job!


New Member
i never really clean very good my uncured LR and it's in the tank for 5 weeks now and there a white,black, and some brown stuff in it. is it ok if i just brush it there and change the water after that or do i need to take it out ang clean it? in case i took it out am i going to start from the beginning of the cycle again and am i going to lose the bacteria in it?


Active Member
Precured live rock is still always going to need to be cured for a little while if it is shipped to you. However, precured rock generally only takes a week, two at most, rather than three to four weeks for uncured.
As far as scrubbing live rock when it is already in your tank: I would take it out and scub it, then rinse it off before putting it back in. Even though you are still cycling, it will cut down on the foul smell and it will look better. Most of the beneficial bacteria is believed to live inside of the rock, so scrubbing it and rinsing it is unlikely to cause much problem for the bacteria.


Hi Mud. Great article. Question for you- do you think that my RO waste water would be good enough for rinsing live rock. How about water that has gone through the RO stage, but not the DI stage? It's a new tank so everything will have to be cycled. I'm trying to find uses for my RO waste water because I just hate dumping it down the drain. Thanks.


Active Member
RO waste water is probably going to contain a fair amount of silicates. Actually, this water may contain superconcentrations of silicates. That would be my main worry.
Whenever I had to rinse a live rock in the past I used water right from the tap. This always led to diatom blooms a few days after the rock was added to the tank.
I would use RO or distilled water to rinse live rock if at all possible. The only reason I used tap water was because I was being cheap and lazy. I would probably use tap water again if I was in a pinch, but I highly discourage it if you have other means.
There is also a chance that the tap water will kill stuff on the live rock. I definately would not use anything but distilled or RO water to rinse already cured rock.
ps- I actually did an experiment with one chunk of live rock where I tried to cure it in saltwater made from unfiltered, chlorinated tap water. After four weeks the rock was still not even close to curing, so RO/distilled water is absolutely mandatory for the plastic container you are curing the rocks in.


Great article!!! I wish i had read this before even buying the LR. I just set up a 75G. The salinity was perfect and i let the powerheads run for over a week before getting the LR. So far i have only purchased 50 pounds of uncured. I was told by the LFS that the tapwater here in Anchorage would be fine to use, but RO better and there is even an RO Water Shop right down the street. 50 cents/gallon.
I scrubbed the rock but not good enough according to your article. I'm thinking of taking it back out and scrubbing it again. The LR has been in the tank for 5 days. At the 2 week point i may add 1 or 2 average size pieces of cured to help out. I'm also thinking of adding a raw peeled shrimp when i take the rock out to scrub.
My question for you is...can you write a FAQ on Live Sand?
I bought 80 pounds live sand and haven't added it to the aquarium yet. At what point do i add this and does it take any time to "cure". What exactly is LS?
If i let the bags sit for 2 months before adding it, will it dry out and be unuseful?
Thanks again!


Thanks mud. You answered alot of my questions about how you go about curing LR and saved me the trrouble of posting the question on the message board. You ROCK


Active Member
Originally Posted by pas13
I'm trying to find uses for my RO waste water because I just hate dumping it down the drain. Thanks.
Terrestiral plants love the stuff. They can make use of the extra minerals. Just make sure the water pours through the soil, and doesn't just build up a sediment in the bottom of the pot.


I have a question.. i already have fishes in my tank... and i got about 20#s of LR and 20# of LS in my tank.. if i want to add more LR....(i acctuly am thinking about adding more rock in there).... how many lbs can i add at a time for my system to safely accept the bioload?
i was thinking if i add about 5-6#s at a time it shoudlnt be too bad?


Active Member
I have personally added about 10 pounds of uncured rock to a 55 gallon tank without any affect on the water parameters. This was after a hearty scrubbing with a stiff-bristled brush and removal of other dieoff with a screwdriver.
The only fish I had in my tank at the time were damselfish which are very hearty. I do not recommend adding 10 pounds of uncured live rock into a 55 gallon or smaller tank with more delicate fish or inverts. I actually had a foul smell in my room for about 2 weeks after adding the 10 pounds of live rock, so you have to keep that in mind as well.


so to say if i add say like < 10#s of CURED rock at a time ... even after i have a few moer fishes in there shouldnt make to much of a difference to the water levels rite?


Active Member
If you cure it throughly first, it won't be a problem, and you can keep that smell someplace you mind it less.