Curing Live Rock

We don't know if we can say anything about curing live rock that hasn't been said before ... many times, in many places, but we bet we can say it differently!

Here's a set of instructions and ideas for your handy reference.

If you only learn one thing here, the most important thing is that ...


You can cure a hundred pounds of live rock in twenty gallons of water if you change the water every day or more. You can cure a hundred pounds of live rock in a thousand gallons of water without ever having to change the water.

The most common mistake made in curing live rock is to try to "save" $10 or $20 on salt mix and let the curing rock kill itself with ammonia by not changing the water often enough.

We're big fans of Rubbermaid-type tubs and trash cans. Garages and or basements are handy if you're happily married and want to stay that way. During summer, outside is not out of the question with a good safely-used extension cord ... most of the stuff we use is waterproof.

Once you've ordered your rock, it's time to get the water ready in the bucket, can, vat, tub, or vessel of choice (or, in your tank, if it's a new set-up.)

Be SURE to scroll down at the end of the article and look at Ray's tank, where he cured his Tonga live rock, with a note from him about the process. Thanks again Ray !!  

Brett's Curing Set-up

One of our customers shared his "vessel of choice" with us, which is a great curing set-up.
Thanks to Brett of Marlette, MI for sharing one of his photos with everyone!

The kiddie pool works great as Brett shows above. Big tubs are good too, but get sturdy heavy duty ones. I might use a 35-gal. tub for 40-65 lbs. of rock and have a 12-gal. tub for rinsing and washing. Having room for more water gives you a buffer against ammonia burn, but you still have to change it.

Salinity and temperature are the two things that matter at this point, although, don't sweat being "spot-on" any given point. I like curing lightly, by that I mean "lowish" salinity, and temperatures. Your water should be somewhere around 1.020-1.021 specific gravity (s.g.), maybe 1.022, and the low '70's for temps, if you can do it without a chiller, but don't worry if it stays warmer. I prefer 72-75° F. — by being cooler, daytime heating doesn't overheat the water, and oxygen levels are higher, which speeds curing.

The lower salinity (besides the lower temperature) will help the rock cure faster. It will not negatively affect the rock to have it at lower salinity and cooler temps the first week or two. After the second week, you can raise the temperature or salinity to levels near where you will be keeping it in the tank.

Note these are not suggested parameters for running a tank, but for curing the rock most quickly. Warmer and saltier will work, but usually slightly more slowly. 1.022-26 s.g. is fine, as is 75° F.   It will not cause a problem to go higher than that, it will just cure more slowly at 80 degrees. Other things, such as how often you change some water will be more important in determining the outcome of your curing.  

When the rock comes in, you should inspect it. If very encrusted with soft spongy material you might use a putty knife, or screwdriver, but if not obviously spongy, preferably a rubber-gloved finger to search for soft spots. Sponges are often disguised on the surface and can be essentially invisible. You can only tell if it's not rock by pushing on it. Using bare fingers, expect to find things like hydrozoans or bryzoans with glass needle daggers of pain and names like fire this and fire that. Chip any soft spongy parts away. I like to use fish cleaning gloves for handling live rock.

Sometimes there may be soft algaes, or many animals, such as anemones, but you should recognize non-sponge things. Sponges die in the air, so forget them ... they will regenerate from the smallest trace of spores left anyway.

IF they are there, getting rid of the sponges will take a week or more off of your cure time ... they'll die and foul your curing worse than anything, so get rid of them first while washing your rock from the get-go. Many places now are finally pre-cleaning them off the rock, and often if there is a place on your rock with "nothing," it is where they took sponge or somesuch off. But check for them.

Most bare patches on your rock was where they had to remove something in order to comply with Fish & Wildlife regulations. But, the spores of the roots are in the rock, and if you keep it clean enough while curing, it will likely grow back. I had encrusting Porites grow out of live rock a year after curing, which hit 8.0 ammonia (pegged) because a dingbat (NOT ME!) never changed the water while curing! So it is pretty hard to mess up, but you can help it on the way with a little good husbandry.

Now, after checking and, if need be, cleaning each piece, shake it out as you do so repeatedly, put it in the tank or tub. Carefully get all the grime and grunge and rubble you can out of the bottom of the box, watching out for bristle worms and mantis shrimp ... toss them out, or confine them if you want them and are a glutton for punishment. They are virtually unheard of from our customers, live. But you may see them in the bottom of the box DOA. The two to three day trip from the island to you usually does them in, if present.

This gooey, grungy, mucky, ugly stuff in the bottom of the box is the most valuable pound or two you get! It should be 20 bucks a pound at least. It is the most bioactive stuff you'll ever hold and it's ready to have a bioactive explosion in your tank ... there is no better seed. Put this in your tank as if were gold. Some people beat the daylights out of it in a bag (use about four plastic "fish bags" and a mallet ... uh, er, so I heard) to make sand out of it before they put it in. Good if you had a bad day ... or want sand. It will NOT hurt the bioactive properties of the PHG (precious holy goop).

The other best things on your rock, you can't see. Those are the seeds and spores of everything that lives in the ocean ... no telling what ... maybe corals, such as acroporas and leathers, or mushrooms, clams, and blue sponge. I've had reports of everything including purple and blue zoas! I've seen it all grow out of live rock three to six months and even a year after I got it.

The sad truth is that most Pacific live rock is held a couple weeks or more out of the water, often on the floor of a warehouse, before it leaves L.A. Then it goes to the store or distrubutor, so the time involved kills most of the good stuff on the rock that might have been there. Fresh rock that hasn't sat around for a couple of weeks or more makes all the difference down the road. Though purple coralline may come back after a couple weeks out of the water, little else does.

Now that everything is in the tank or tub, there are two major new concerns: circulation and ammonia removal. A couple of strong powerheads should move the water around enough. Some kind of skimmer should be hooked up to help pull out excess proteins, of which there will be plenty. Otherwise prepare water for every other day (or more) water changes to keep the ammonia from getting too high. Five or ten gallons a day or every other day at least is not too much to be changing. Twenty gallons if it stinks, is yellow, or your skimmer cup overflows too often. If you are not skimming, change more water ... the solution to pollution is dilution.

I often use Bak-Pak skimmers for this with great success, but any skimmer will do. I'll often throw a carbon filter of some sort on for this too. Like in a Hang-on-Tank Magnum which is handy to have. But just for curing. I don't run carbon in the tank. In a couple or a few days, you might need to rewash the rock and recheck it for areas of die-off that need to be removed.

Flip the master switch to shut off the juice (I keep all the electrical equipment used on one multi-plug strip) ... plugged into a GFI plug. That way, I can flip one switch and everything goes off at once, so I don't have to remember if I unplugged the heater and siphon about 5-10 gallons of water into the "sub-tub" - the smaller 12-gal. tub.

Siphon up to half or more of the water out of the tank or tub the rock has been in, and toss it, replacing it with warmed (if need be) new water. I make mine in 5-gal. buckets or a small 20-gal. trash can, to have it ready in advance, heated, airstone aerated, and all.

So now the rock has been cleaned and recleaned, and you probably have two or three days before you should change more water. You should be testing for ammonia and if it's spiking high, make a water change. Don't skimp on water now!  


Of course, the whole time the protein skimmer has been going nuts and you can't believe how often it's full and needs dumping. You may want to hook up a drain hose to the cup, airline tubing may work, or some 1/4" tubing.

I think it's a waste to make tests as often as some indicate at first (daily), because you don't need to be a marine biologist to tell it's bad! Most folks without a degree would agree, it's bad! Unless you like watching the colors on the charts, bars, in the tubes and such.  

After a week, test the water every two or three days as the ammonia level drops. Somewhere between two and three weeks, the skimmer will stop wheezin', and the ammonia will drop to zero. The main spike (and smell) is in about 10 days or so. We have many customers report that it cures in two weeks to three, because it is A) so fresh, and B) they kept changing water and skimming heavily.

After the first week, as things begin to calm down, you might see the first signs of life on your rock, but it usually takes two weeks. Inspect it regularly during the second week and beyond, particularly with a flashlight at night to see what you can't in the daytime. This is the best way to find any unwanted hitch-hikers, though they are rare.

When your ammonia goes down to zero, you've done it! There are now more ammonia-eating bacteria than ammonia being created. Now you can grow a bacteria farm in order to support the animals you want! It's the bacteria farm that does it, don't forget! Your live rock is cured, and it is time to move it to the tank if you did it in tubs elsewhere. While I would be careful to not move the curing water to your tank, I would be equally careful to get every bit of sand, rubble, grunge, etc., of the bottom of the curing vessel and put in in my tank or sump. Who knows what might be there?

Customer Reef Tank

A great looking reef built with a combination of our live rock ... Bali, Java, Vanuatu, and Irian Jaya. Thanks to Graham S. for the photo!

When aquascaping, it may take several arrangement attempts to find one you like best. Good rock and a good set up look like a real reef. There are plenty of pictures in books and on the Net. Our customer photo page has many EXCELLENT examples of how one can creatively make an absolutely authentic appearing sea scape with our live rock.

Open, airy holes, hangovers, but SOLID OF CONSTRUCTION is the key. I lived where there are earthquakes, and shaky set-ups can break a tank! Make sure everything is wedged in hard and well, perfectly, so as not to move and in no question of falling.

Remember ... you are going to be placing corals on it, and it must hold them, without any chance of falling. You'll have enough of that placing the corals anyway. Wait until you see how that 3" Elegance opens up to 8", with the weight of the meat causing it to fall off from where you put it ... I once had a Galaxea fall into a Leather and kill it.

So, after much looking, moving, and re-arranging of your rocks, you'll finally be satisfied with their place and position. You are now ready to acquire your first fish and coral specimens. It cannot be overstated to go slowly at first. Remember any copper will kill all the good stuff you've worked so hard to keep alive, so never consider it.

Always quarantine new fish elsewhere before you put them in your reef. It is entirely possible you will introduce many parasites, bad bacteria, viruses, and diseases on pieces of corals you purchase. How can they possibly be sanitized against such? There are probably things on them that haven't been identified or named, much less have we a way to cure them! If you can't QT them, always dip your corals, just as you would a fish to sanitize them, before putting them in your tank. Any SPS dip, or strong Iodine solution like Lugol's or somesuch will do.

It's a fact of life, but a properly cared for tank should be fairly immune to these things like ich, etc.; they may even be food to corals. Under the stressed situations of excess ammonia, dirty water, etc., these things can be devastating. In a healthy, clean tank they rarely have an effect.

If you can bear it at this point, after all this waiting, it is not a bad idea if it took two weeks to cure, to let it go a couple or few weeks after the rock is cured before introducing anything just in case any parasites will die off, starving prior to introduction of any potential host species.

Don't put more than a couple of hours of blue light (if any) on it while in the first couple weeks of curing. It won't hurt it to cure without light, but don't use your bright tank lights to cure. Your worst enemy would be an algae outbreak, so don't encourage it. And when you move it to the tank, or after it's cured, get snails on it right away when you start hitting it with real light.

For the first week after curing, start slowly with lighting, a couple of hours of blue light before and after a couple of hours of white-daylight. Then increase it to four hours a day of white-daylight between the sunup and sundown blue period (which is very important folks). Slowly build up to a 8-hour daylight photo-period, with a couple of hours of blue light dawn and dusk on either side of it, like how it really is. And get grazers on it right away when you start the white daylight intense lighting.

Taking your "significant other" (wife, husband, girlfriend or boyfriend), or any housemates (children, roommates, siblings, parents ... whomever) out to dinner often during the curing process may be recommended or desired. (If you have a dog, it may need a fresh air walk too!) Your cat will love it.  

HAVE FUN with your rock!

(Just watch those "nose smears" on the glass!)

Kept my first corals in 1977!

Live Rock

Thanks to our customer Ray of Ellicott City, MD for his comments and photo!

Here is what he shared ...

"Thanks again for the great Tonga reef rock. I've many things still alive and making their way around now in the reef. The zoanthids are moving into location, and I've spotted a feather duster worm today.

I think that by treating the rock well and providing the best conditions possible throughout the curing process, the process itself is not only drastically shortened, but more life makes it through as well. I know, "well, duh." Iím looking forward to the next few months with my nose pressed against the glass! I'll be in touch again!"

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