Should You Use Cured Or Uncured Live Rock?

Live rock has become a widely used media for filtration. It is a natural way to filter and it deals, within reason, with the full [tag-self]nitrogen cycle[/tag-self]. It is suitable for all marine aquarium systems, and is usually very successful if the quality and quantity are correct. In addition, it is an excellent aquascaping material, lending itself very well to rock formations (well, that‘s not really surprising is it!).

Seems the thing to use then as far as filtration and aquascaping are concerned. Properly used there aren’t any real drawbacks. There is one drawback though, and that is cost. Most aquarists use rock that has already been cured, as it is more convenient (I hate to use the word ‘instant’ in a hobby where patience is so important) and just pay the premium.

Why the cost? As the media is rock, it is bulky and heavy, though the weight does vary. Therefore the air freight costs are high. Many an aquarist could be taken aback by the potential bill for sufficient quality live rock.

Is there any way to reduce this cost? An obvious way is to use a different filtration system, such as a canister or trickle filter. These are not as efficient in bio-filtration as live rock as far as the coverage of the nitrogen cycle is concerned. In addition of course, rock still has to be purchased to decorate the aquarium though it will be a lot cheaper.

There is a way to buy live rock that is notably cheaper, and that is to choose uncured live rock. Live rock is cured often by the retailer, and this time and effort, plus the equipment needed to achieve it, has to be paid for.

‘Cured’ live rock! What happens, is it injected with a special medication or something? No, it simply means that time is given for the life on the rock to die off, so that the aquarist can put the rock to nearly immediate use.

Live rock is collected from around the reefs, and consequently has all sorts of growths on it. These life forms have varying degrees of toughness, and a great many succumb to the rigours of transportation and changes of environment. Those that are left could add to the interest of the display aquarium (or not, depending on what they are!).

It is the loss of life that is of concern. It is well known that ammonia and nitrite are toxic to aquarium life and need to be avoided. As the dead life forms on and in the rock rot, and those that are dying eventually rot, toxics could reach high levels. This would be death to aquarium livestock. Therefore the rock needs to be given time in a suitable environment for this cycle to pass. Some life forms may die in the curing process because of the high toxicity.

The retailer will have tanks that are used purely for curing live rock. They will be fitted with efficient protein skimmers and the rocks will be covered with seawater. In addition there will be good circulation present, and the temperature will be maintained at an appropriate level. As time progresses, the ammonia and nitrite cycle will pass, though this period could be quite protracted. It is this that the retailer is watching for, testing to ensure that it is clear. The rocks are often then rinsed in clean heated seawater, checked and put up for sale. The rock is considered as cured.

So how does this assist the aquarist? There aren’t any additional aquariums (usually) for doing the curing process. There is only one place it can be done, and that is in the eventual display aquarium. So let’s look at that.

The aquarium is 2/3rds full of seawater, at the appropriate specific gravity (SG) and temperature. If the rock is going to eventually permanently stand on a supporting grid then this must have been completely organised before water goes in. The rock is not put into the aquarium in a decorative way, just put in. Before this, the rocks are carefully inspected for any obviously dead or dying and rotting life forms, which are removed as efficiently as possible. Some aquarists actually scrub the rock in warm seawater, but this may damage desirable life forms on the surface that might have survived. If scrubbing is done, a separate container is used – a large bucket or whatever – to keep scrubbed off items out of the main tank. As the rocks go into the aquarium, so the water will rise. If too much water is present, then it can be removed. If otherwise, it can be topped up.

Apart from heaters, the aquarium should be fitted with seawater circulators. These will be required when the display proper is ready so does not represent an additional expense. An efficient and appropriately sized protein skimmer should be switched on, again this will be required anyway. During the curing process, the protein skimmer should be regularly checked and cleaned when necessary (as when the display tank is properly functional) so that its efficiency is not reduced.

It will take time for the curing process, often counted in weeks. Any ’rubbish’ seen on the water surface or in the lower areas of the tank should be removed as far as possible, a fine net is useful for this. Also watch out for unwanted hitchhikers, such as crabs, mantis shrimps etc. though it is likely they will not be seen in the pile of rocks.

The aquarist should have three test kits available (again not an extra expense, they are required when the display tank is being stocked to monitor water quality). The kits are ammonia, nitrite, and nitrate. At first, after say three to five days, ammonia is checked. When this is detected, in the following period it is likely to rise. This can be monitored, and checks for nitrite commenced. It is not necessary to check every day, but when ammonia ceases to rise and begins to fall or disappears, nitrite checks can be done more regularly. Ammonia is at the front of the nitrogen cycle, and bacteria convert this to nitrite. Therefore if nitrite is present it shows that the initial bacteria battalions are at work. Nitrite may continue to rise, then start to fall or disappear. At this point check for nitrate, as this is the next to appear in the cycle. Nitrate could continue to rise to quite a high level, but should level out. This indicates that the nitrogen cycle is effective and has converted all toxins (ammonia and nitrite). Is this the end of the story? As far as the nitrogen cycle is concerned, the answer is no. Live rock is able, within reason and with time, to convert nitrate so that it can escape from the seawater as gas. It is best to let the nitrate fall a little, showing that nitrate conversion is in progress. The live rock is now nearly ready for use.

There should be available an amount of freshly mixed seawater, of the same SG and temperature as that in the tank. The amount should be equal to the largest volume that can be stored, say 20% or more of the tanks gallonage.

If necessary, lay a waterproof covering on the floor which is large enough to hold the live rock. The live rock can be piled up if necessary.

Remove each piece of live rock from the tank, giving it a rinse by moving it back and forward. If the following is going to take a little time, then the rocks can be covered in seawater dampened newspaper.

Siphon out some seawater, making sure that any debris is removed. Continue siphoning until the seawater removed is a little less than the new stored seawater. This can be done by measuring it out with a known volume bucket. This seawater is going to be thrown away, but keep the last bucket.

Now is the time to put in the decorative sand bed (pre-cleaned sand) if any. The live rock can now go back in, aquascaped as the aquarist desires. The water level will again rise, but be short once all the rocks are in. The new seawater can now go in. If the water level is a little low, use some from the bucket that was kept. Once at the desired level in the tank, all old seawater can be thrown away.

A check should be made that the heater(s), circulation devices and protein skimmer are in position and switched on.

The tank can be left for 24 hours, then the aquarist can do another ammonia, nitrite and nitrate test. Ammonia and nitrite should be undetectable. Nitrate is likely to be present. The guideline target for a reef tank is 10 ppm (parts per million) or less. If it is higher than this, the aquarist has two choices – wait and see if the bacteria in the live rock reduce it (this takes time) or do a further water change. The level above that desired will assist in the decision.

So the aquarist is now ready for stocking. One of the good things about curing is the high ammonia etc that is likely to arise, which means there is fuel for the bacteria – which means that the bio-filtration should be ready for livestock. However, this cannot be taken for granted and checks of ammonia and nitrite should be made as the display is slowly stocked. Nitrate needs to be monitored too.

It will be interesting as the age of the display increases to observe what life actually appears from the live rock. It could be various types of algae, small worms and the like. The aquarist will have introduced perhaps the best bio-filtration available, reduced the cost considerably, and, all things being equal, should end up with a wonderful marine display.

  1. Nice article!
    I have supplemented “cured” lived rock for years at a ratio of 1-5 cured live rock to uncured (usually dry non-reef harvested) rock.
    This requires more patience on my part and the clients I set these aquariums up for, however there not only is a cost savings, but a saving on reef depletion as any porous calcium based rock works well. I generally used rock mined from areas that were at one time under the sea finding these rocks best.

  2. Thanks – glad you enjoyed the read.

    Good points you’ve made, both on the conservation aspect and saving money.

    My soft coral reef started with most rock being dead, which is now live as I introduced live rock as time passed. I cannot state the ratio though it was low.

    John’s last blog post..Should You Use Cured Or Uncured Live Rock?

  3. I just got a good hand full of dead Coral from a family member. do I need to cure the coral? The coral has bin in a saltwater tank 20 plus years ago. The coral has bin stored in boxes in the garage for 20 plus years high and dry. WHAT DO I DO, HELP!!!! THANK YOU

  4. Hello Tony.
    The reason new or fairly new ‘live’ rock is cured is to rid it of dead or dying lifeforms that could otherwise cause pollution and trouble. The coral you have has not had any life for 20 or more years so there isn’t going to be a problem in this way.
    It will be worth giving it a thorough rinse in fresh water, a hose could be used. It shouldn’t be very dusty as it has been in boxes but there may be bits of loose coral etc that will be washed clear. Allow to drain thoroughly.
    With a new aquarium remember that when the coral is in the aquarium it will be decorative but will not contribute at all to the biological filtration process as there will not be any of the desirable bacteria present to deal with ammonia and nitrite. Therefore there is a need for a canister filter or, better, ‘live’ rock to deal with this process. If a canister it will need biologically firing up (there are commercial liquids available for this just follow the instructions). If your aquarium is running and matured then no problem.

  5. My Tank is over 1 year old,. I have 98LBS of live rock in a 75 gallon tank, and lots of good purple coraline algee. I have under the tank a 175G rated aqualine wet dry trickel filter, a Reef Octopus NWB110 Protien skimmer, 2 1300GPH power heads in the tank.and a total of 10 fish. I the box of dead rocks there is dead CORAL can I put the coral in the tank at all or is it not a good idea. you can go to youtube and see my tank just put in the search box tonyvtc3. I know i will have to cure the 30LBS of dead rock but how about the dead white coral. thank you for your help that you sent me on Dec-28-2011 good info.

  6. Hello again.
    If the dead rock you have has been stored as long as 20 years (or quite considerably less) it will not need curing – there will not be anything dying and anything dead should now be a dried up husk. Give it a good rinse to remove oddments then allow to drain before it goes in your aquarium. The rock will become home to bacteria etc as time passes.It isn’t ‘fashionable’ to have dead coral in reef tanks nowadays as it is frowned on from the conservation point of view. However, as the dead coral is already with you, if it fits in ok physically and aesthetically, then why not use it. All it needs is a good rinse and drained.

  7. Thank you for your knowledge. In the e-mail it talks only rocks, then I looked at what you said above and bingo!!! Thank You again from: Tony V

  8. I’ve looked at your aquarium on YouTube. The fish give it plenty of movement and in general everything looks good. The rock close ups were interesting. In my view, all it needs are a few corals, preferably soft types as they sway in the currents nicely, have lovely pastel shades and are generally hardy in good conditions. It’s not my system though, it’s yours!

  9. Thank you John: I am still working on the tank. I just got or should I say the Fish/Tank got for Christmas the Deep Blue Solar Xtreme Quad light fixture with lunar LED’S model 448. I will give it some time, now the Next step it to make my own add on Refugium to my WDTF. I will have a new vid on youtube with the new light fixture it looks awesome. THANK YOU SO MUCH YOU AND THIS SITE ARE AWESOME!!!!!!!!!!!!!!!

  10. Hey John Happy New Year! Again thank you for all the Info. I am looking in to to building my own Refugium to add-it to my WDTF, After the New Year I will need some in-put on plumbing and locatoin for a add-on refugium, or if you know of any web-sites that can give me plans or some know how. thank you much Tony V

  11. Happy New Year. Try this for some information:

  12. Thank you again John that Refugium art… helped me ….. Well the new light i got the Deep Blue pro SolarXtreme 448 BROKE!! 17HR later, and so I took it back to the pet store and the owner swap it out no problem to a Coralife Quad / led light fixture and it is working great so far. The store owner said the some people have had problems with Deep Blue products.I am not saying don’t buy the product just look out and do the research you can save time and money… >< I hear they have a good warranty also. take care and Happy New Year to all…..

  13. I just got a leopard goby and i need to know if copepod are ok for this fish i put a bottle pods in the tank just to start some where. my 75 gallon tank has bin going for 1 years PH 8.2 AMO “0” NITRITE “0” NITRATES “0” CALCIUM 480. SALINITY 1.022 I made my DIY refugium i have 135LBS of rock total in fugi and tank…. 120LBS of sand.reef octopus NW110 skimmer i use a 100mc sock you have seen my vid but i have a new one on youtube go tonyvtc3.

  14. Hello Tony.
    The goby should take copepods ok. It would be a good idea to also offer small cut pieces of de-frosted frozen fare such as fish. They’ll also often take flake if they can get it before others.

  15. thank for the info…. this morning i was look at the leopard goby and it took a baby snail off the glass yum yum, it sucked it down and gone, as my tank has matured over the years out of no where little baby snails made it in to my tank. I do have adult snails and i think they had some kids LOL… So with this being said, tiny snails copepods frozen shrips & flake food should be OK? i will keep an eye on him or her…. Thanks again T.V.

  16. Specs on my tank as of 1-10-2012, 12:00pm PH 8.2, AMO “0” Nitriets “0” Nitrates “0” Calcium 480ppm, Salinity 1.022 and slowly going up for my Reef Tank to be. Again thank you for your info and help.

  17. I have started to using Instant Ocean salt mix at the start of my saltwater Aqurium hobby 1.5 years ago. Now i am using Instant Ocean Reef Crystal salt mix, #1 to slowly bring my salt levels and #2 work my way in to A Reef Tank. I have heard that Red Sea salt mix is one of the top brands out there but its price is well you know. can some one let me know if i am on the right track to have a successfull Reef Tank and my point is can i stay with Instant Ocean Reef Crystals for now!!! thank you John.

  18. There seems to be no reason why Reef Crystals can’t be mixed in so that the overall seawater changes over time. There are several reef salt mixes, I use a German one and haven’t any complaints. Nowadays they all seem to be pretty good.

  19. Need help i just got a rose bubble tip Anenomy MY FIRST SOFTY!!!! I think it pink not sure if it will turn red. My quastion is how to take care of it, I am feeding it shrimp i put marine garlic in my food mix to help the fish I am new to softys this guy is verry small 1.5 X 1.5 inch. I put it in the tank front and center i knew it would move to find a spot that works for it, i am cool with that. I will still look for more in fo from the net and the store where i got it from. i just want to see all the differant opinions that are out there. thank you John. If you know of a goo artical or web site let me know…

  20. sorry my bad (Anenome). My speilling is bad. One more thing my tank is all most 2 years old and doing awesome (ph 8.2) (amo 0) (nitrie 0) (nitrates 0) (Calcium 480PPM) I test my water with API Saltwater / marine teast kit.

  21. Hello Tony.
    Really pleased your system is doing well. Now it’s two years old it should be really mature and stable.
    Anemones do have the sometimes annoying tendency to wander until they find an area that is pleasing to them. Often they’ll get in a crevice so that the foot is protected. They like seawater flow but not too strong. This anemone could grow to around 12″ in diameter in good conditions. For it to retain its colour it needs strong lighting such as that provided for a reef system. The anemone is able to damage corals if it touches so it should be kept clear of them. When I kept an anemone along with its clownfish I fed the anemone small pieces of de-frozen fish which it took readily, though the clownfish was quite happy to steal the food. It is quite easy to overfeed an anemone, it just needs twice a week or so, a smallish piece. Generally care of the anemone is as you have – high quality seawater plus reasonable not too strong seawater movement plus the lighting. As said the anemone could tell you if it is unhappy with its environment.
    Anemones should not be kept by newcomers but you have two years experience so, with a bit of luck maybe, all should be well.

  22. It has bin 2 week i put in a dual Reactor, GFO and Carbon Reactor from BRS in my 75 gallon tank. i need some help on how much GFO to use in my set up, first i went by the directions on the GFO contaner. if i add more than what is recomendid will it harm the tank. plus how long will it take to rid of the algae on my rocks i have some brown stuff on some of them. next i have green bubble algae on my rocks as well i do have a green emerald crab in the tank but it just like to chill out and eats every thing else more then go to work on the bubble algae what to do.

  23. Hello Tony. I would never recommend putting more than the manufacturer specifies in the aquarium. Most things take time to act and sometimes the action can be slow enough that it appears nothing is happening – very irritating. Brown algae can sometimes be the forerunner of good algae ie decorative algae. My own aquarium back glass and some rocks started like this, very patchy, and now there is a lot of various coloured algaes of the pleasant ‘welcome to my aquarium’ types that cause no problems at all as opposed to the yukky green hairy stuff and slime. Green bubble algae – I assume you are referring to ‘sailor’s eyeballs’, small balls attached to rocks (Ventricaria ventricosa). In this case the problem is that once the balls get to a certain size they will burst and release loads of spores resulting in many more. This causes problems with eradication as if the balls are simply burst then …..! One way is to get a length of airline rigid tube, say 12″ or whatever is good for the aquarium, and attach it to some flexible airline which is long enough to reach into a collection bucket. Sharpen the edges of the leading end of the rigid tube. When a routine seawater change is to be done, first use the small bore tubing to attack the bubble algae. Start a siphon, this can be easily temporarily halted by pinching the airline. With the seawater flowing, burst the bubbles but keep the tube on them for a couple of seconds, this will hopefully siphon any spores out. Continue doing this until either the seawater has reached the full amount required for the routine change or the operation is to cease. Empty the siphon tube into the bucket. Obviously, the seawater in the bucket cannot be returned to the aquarium. This method works well after a little practice, five minutes should see the training done! It’s likely that some algae will remain because of the many nooks and crevices present in a reef aquarium. However, control is easily achieved, though takes longer in systems where the bubbles have run amok. In this case, carry out the removal exercise as normal and eventually control will be achieved as the algae cannot outrun the repeated attacks.
    It’s said that seawater quality (very low nitrate and phosphate) should be good if sailor’s eyeballs are present.*
    (*Baensch. Marine Atlas)

  24. Yes that is it Sailer eye ball and yes i did not know and i poped some and now i have more damit man. I use the profi by Salifert phosphate test kit. this test tells me that the PO4 is at (0) and for all my other water test i use API test kit. My Nitrates are at (0) PH(8.2) calcium 420 to 450, as for the KH 8 too 9 drops and test water turns yellow. all othe peramiters AOK Amo (0) Nitrite (0) I do water changes once a week, should i do smaller water changes more often than one large one once a week? Thank you John

  25. Hello Tony. Your seawater is good as suggested by the presence of the ‘eyeballs’. It doesn’t really matter whether you do more smaller routine changes or one weekly that’s bigger. If you intend to use the attack method I suggested pick the routine that is best and least disruptive for you and that has the largest impact on the algae. Remember though that more messing in the aquarium means more disruption – maybe stress – for the inhabitants.

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