Cooking Live Rock


4 May 2007
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I can't remember where I got this from but here it is anyway...

The purpose of "cooking" your rocks is to have the bacteria consume all (or as much) organic material and PO4 stored on, and in, the rock as possible.

The first step to this is commitment.
You have to be willing to remove your rock from the tank.
It doesn't have to be all at once, but I feel if you are going to do this do it all. In stages if that is easier but make sure that all of it gets done.

The new environment you are creating for your rock is to take it from an algal driven to a bacterial driven system.
In order to this, the rock needs to be in total darkness to retard and eventually kill the algae's on the rock and to give the bacteria time to do the job.

So basically you need tubs to hold the rock.

Equipment needed.
1. Dedication.
2. Tubs to cook rock in. And an equal amount of tubs to hold the rock during waterchanges.
3. A few powerheads.
4. Plenty of buckets.
5. A smug feeling of superiority that you are taking it to "the next level." View attachment 61200

Here are the steps, if you have any questions I will try my best to answer them. What I don't know I am sure Bomber can/will instruct.

1. Get into your head and accept the fact you will be making lots of salt water if you aren't lucky enough to have access to filtered NSW.
2. Explain to significant other what is going on so they don't flip out. This process can take up to 2 months. Prepare them in advance so he/she can mark it on the calendar and that they won't nag about it until that date arrives. View attachment 61201
3. Setup a tub(s) where the rock is to be cooked. Garages are great for this.
4. Make up enough water to fill tub(s) about halfway and around 5-7 buckets about 60% full.
5. Remove all the rock you want to cook at this stage. (The rock can be removed piece by piece until you are done.) I suggest shutting off the circulation beforehand to minimize dust storms.
6. Take the first piece of rock and dunk it, swish it, very, very well in the first bucket. Then do it again in the 2nd bucket, then the third.
7. Place rock in the tub.
8. Repeat steps 6 & 7 to every piece of rock you want to cook at this time. The reason I suggested 5-7 buckets of water will be evident the water quickly turns brown. View attachment 61202
9. Place powerhead(s) in the tub and plug in. Position at least one powerhead so that it agitates the surface of the water pretty well. This is to keep the water oxygenated. You can use an air pump for additional oxygenation if you wish.
9. Cover the tub. Remember, we want total darkness.
10. Empty out buckets, restart circulation on main tank.
11. Wait.
12. During the first couple of weeks it is recommended to do a swishing and dunking of the rocks twice a week.
What this entails is to make up enough water to fill up those buckets and the tub the rock is in.
First, lay out your empty tub(s) and fill buckets the same as before.
Then, uncover tub with the rock in it. Take a rock and swish it in the tub it's in to knock any easy to get off junk.
Then, swish it thru the 3 buckets again, and place in the empty tub..
Repeat for all your rocks.
Then empty the tub that all the rocks were cooking in, take it outside and rinse it out with a hose.
Place tub back where it was, fill with new saltwater, add rocks and powerheads, and cover.
Wait again unti the next water change.
You will be utterly amazed at how much sand, silt, detritus is at the bottom of the tub and every bucket. It is amazing.

How it works:

Some FAQ's.
When re-introducing the rock to my tank, a month or two from now, should I do that in parts to help minimize any cycling effect(s)...if there are any?
I never have. Really after a very short while, the ammonium cycle has been established. That's not what you're worry about though, it's the stored phosphates and that you have to wait it out.
When they are producing very little detritus - you'll know - then I would use them all at once.

Would running Carbon filtration and/or a PO4 reducing media help/hurry/hinder the process?
I wouldn't fool with it. You don't want the detritus to sit there long enough to rot, release water soluble P again. You want to take it out while it's still locked up in that bacterial detritus.

I hope this helps you out.
It really is a "miracle" and a low cost one at that.
The only monies spent are for salt and electricity for the powerheads which are nominal. Especially to rid yourself of Bryopsis.
Time and effort is all it takes. And really not that much effort.
I would say that 85% of my exposed rock had Bryopsis (hair algae) covering it.
There isn't a single visible strand on any rocks in the tubs now.
Remember, the key is patience. Let this process run its course.

And a few last minute tidbits I remembered.
Your coralline will die back, recede etc.
My thoughts on this are GREAT!
Now my rock is more porous for additional pods, mysids, worms etc.
Coralline will grow back.
Throughout this process the sponges, and pods on my rock have not died off.
Everytime I do a waterchange they are there and plentiful.
The process works well. I cooked about 20 kg's of seriously infected live rock. I cooked it for about 2 months and re introduced it to my system. The rock is thriving now and covered in corraline ;)
Hey been throught that long process already!!
2 months for me also!
Its damn tiring, trust me!! But well worth it at the end!
Now i dont have a single strand of algae. In fact i wish some wolud grow for some food for my tang!!ha ha!!!
Naah, just happy they all gone!
You will get there viper!! Like the article says, PATIENCE!!:)
Ok I did not see any mention on a skimmer there? I'm about to go this route with some rock as I'm not winning with the algae, I have some "new" rock that has been in my sump for a good few weeks and all the other rock will be cooked, so NO skimmer?
Good point there SIMS, maybe the author left it out??? But from other articles I have read I'm sure I can recall them all mentioning heavy skimming.
Excellent article thanks Dean. Have to deal with hair algae now after my overflow abortion..
Quote.."Throughout this process the sponges, and pods on my rock have not died off.
Everytime I do a waterchange they are there and plentiful. "....

This statement is misleading
I subscribe 200% to the philosophy of cooking....with the following additions...

Firrstly..Many sponges (porifera) are mixotrophic. They feed not only on DOM and nano plankton but some that are found in our tanks also share a symbiotic relationship with cyanobactaria(photosynthetic). In short this means that they either need to filter feed from a higher than normal nutrient levels and or small amounts of light.

This is not how we cook....we want sterile low nutrient levels and no light.

Secondly... it is a well known fact that air is lethal to sponges... take them out the water... even briefly and they will most likely die.
By the time our live rock reaches sunny South Africa, it has spent a good few hours out of the water. One rock that i have recently cooked was Kenyan... Sponge density on and within is amazing. I have witnessed fresh rock arriving; and then the decay....indicated by grey or white the decay worsens the rock literally oozes a translucent grey jelly.... which eventually leaves dark/blackish bruising which almost seems to stain the interior of the rock... This has led me to believe that many of these colonies actually survive within the rock.

Skimming indicates massive dye off for at least a month. Sulphur dioxide reeking skimmate by the bucket full. Month two darkish brown...month three clear.

imo.. Shake and blow clean with a power head...But i dont believe in scrubbing as Kenyan is so fragile that even after a light scrubbing it begins to crumble and disintegrate..... Heavy aeration and skimming to blow off ammonia...and as much circulation you can provide....The bigger the volume of water used the better...dilution...Carbon and phosphate removal 24/7
Cool, nice info Sean ;)
Great thread! can we have some pics? Of before, during, junk in buckets etc please?
Ok need some help with this thing - I have a bucket about 100l with an AM1000 and a Rio 4000l pump...

Does temp make a difference to the cooking rock ie. do I need a heater?
What should my SG be?

Anything else I should watch out for?

If you take all the LR out your tank to do this wont it have an adverse effect on your filtration and destabilise the tank? How do you manage to keep the water params stable with no LR in the tank for 2 months? I suppose what I am asking is how do you manage the tank the LR has come out of especially if the main reason is to kill off hair algae.?

Good question Muz - for me I have a 300l display and a 200l sump - I am skimming quite a bit (skimmer rated 1500l) I have good circulation (x50+) and have 30kg's of rock in my sump - Plan is to cure this for a few weeks - no algae that I can see and then cure the rest once that is done so I will have 30kg's + in the systemall the time.
Ahhh, so you are in the fortunate position to rotate your LR cos you have doubled up.. our systems are about the same. Funny ( not funny Ha ha ) but I only have hair algae on one rock, it is covered, not one square cm untouched, all the rocks next to it are fine. I dont have a lot of space in the sump cos my DSB is really deep so 30kg's wont fit..

Interesting though.. I read an artical by Anthony Calfo and he mentions very heavy skimming during this process.


Won't tangs solve the algae problem ??
I have 2 lawnmower blennies, yellow tang and Regal tang no diffs.

Muz take that rock out before it infects the rest of your system, even if you have to kill it get it OUT!
Geez dude, I'm running to my tank as we spea...
:lol: serious though that's how it started with me now I look like Viper....
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Not to invent the wheel but if I ousted the rouge rock to the sump would that not at least 1) remove the algae from nearby rocks 2) the nutrients that are feeding the algae will be diverted to the algae in the sump..

or.. remove him and scrub his naughty ass?

If the rock has been in your tank awhile; then can the scrubbing. Just treat him like a mushroom, stick him in the dark and feed him.....well not quiet like a mushroom.

I have frequently had this happen where one rock suddenly sprouts flowing locks... and it always seems to be when transferring rock from one tank to another...even tho the tank that the rock came from did not have a problem.
nice info guys!
Ok I unpacked most of my rock from the sump and was suprided to note that they are algae clear not one spec - I have scrubbed them and put them in the cooking tub, skimmer ran 12 hours no foam - should I leave them in there or take them out?
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