Cooking Liverock

irie ivan

irie ivan

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I saw a thread on here somewhere involving old dry rock, which reminded me of some rock i had been wanting to bring back to life and add to my tank for some time, but have just been too lazy.
Motivated, i decided to fire up the "stove," pull out the pots and start the cooking process...
I firmly believe that thorough "cooking" of dry rock, and even the periodic cooking of in tank rock used in sump as added filtration, makes a significant contribution to combatting algae infestations in the long run.
It does entail a bit of work and time, but nothing compared to the frustrating task of combatting algae as a result of substrate bound nutrients.
Any rock which has been subject to total die off, WILL have organics on and bound inside the rock and its consequent releasing of nutrinets into water and fuelling algae has been hashed to death.
Various methods are proposed on forums, from the WAP / Kärcher treatment, to cooking in tubs with skimmers and dripping lanthanum chloride or running in a tub with GFO/H and skimming to vinegar soaking to continuous water changes, etc, etc.
The one I chose, takes only a few days, and a bit of work before rock is pristinely clean and ready for colonization and in tank use.

Tools needed:
- Pool acid, bought at your local hardware, around R50 for 5L.
IMG_4403.JPG

Be sure to read and follow all safethy precations, this stuff is not to be played with.
- A scubbing brush, the harder the bristles the better,
- A spray bottle, available from most supermarkets and garden stores.
- Protective gloves, good strong rubber gloves, as long as possible.
- Protective mask and eyewear.
- Good old kalk / slaked lime / calcium hydroxide, can be bought for dirt cheap from most chemists. Again, follow the safety precautions for kalk usage, do not breathe the dust.
- Bacteria suppliment such as seachem stability or prodibio bacteria.
- Tubs for soaking
- An old powerhead or flow pump.
 
First, give the rocks a good hose off, (good strong pressure will help) with ordinary tap water, whilst scrubbing off any loose bits / die off.
Now they are ready for their first treatment in loosening bound surface organics.
Add water to your spray bottle, then add your pool acid.
Add acid to water, Do not add water to acid, and wear protective gloves, eyewer and mask and work in a well ventilated area.
I use a dilution of 50ml acid to 450ml of tapwater.
Spray the rock thoroughly with this solution, and you will notice the foaming , dizzing and bubbling action as the acid eats into and dissolves the calcerous substrate:

image.jpg
 
Leave the rock to fizz away for about ten minutes, then rinse off with freshwater, whilst giving it a thorough scrub.
Repeat the process of spraying the diluted acid, leaving for ten minutes, rinsing and scrubbing three times.
Once this is done, move the rock to a tub with RO water and and diluted pool acid, let it soak overnight.
I used a dilution ratio of 20L of water to 500ml of acid.
Again, remember to add acid to water and not other way around:
 
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The next morning, remove rocks from tub, give them a thorough scrub and rinse, and discard the water in which they soaked overnight.
Cover the rocks again in RO water, add a flow pump or powerhead, and slowly add saturated clear kalkwasser mix to the tub.
I used one litre of kalkwasser to 20 Litres of RO.
To get a saturated kalk solution, use 1/2 a teaspoon of kalk mixed in a litre of RO water. Stir well and leave to settle. Once it has settled, slowly pour the clear liquid into the tub.
This will raise the pH sufficiently to combat the very low pH in the RO caused by the remaining acid on and in the rock.
Leave this overnight again.
I the interim, start making a salt water mix. No need for a full strength saltwater mix, sg does not need to be higher than 1.020.
 
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The following morning, remove rocks from tub, discard water and give rocks a thorough scrub and rinse.
They are now ready to be seeded.
Obtain a few small pieces of live rock from your tank, or from lfs, crush them and place them and the rocks you cleaned in your premixed saltwater with a powerhead, add your bac in a bottle of choice and keep adding daily as per manufacturers recommendation.
Some people advise skimming at this stage, but i believe its counterproductive during the first day or two, as the bacteria you are adding will simply be skimmed out.
No need for lighting or any othe filtration..
After a few (2-4) days, these rocks are ready to be moved to your tank.
 
image.jpg
Some pics of the rock soaking in diluted pool acid after 5 minutes... and this after a good three scrubs, so we can safely assume this is whats being released from inside the rock.
Wish i knew how to post a video...pretty scary!
 
Admittedly, i did push the envelope a bit and doubled up on the acid
 
Thank you for the very helpful, detailed information!
I know many, many people take the meaning of "cooking" rock literally and don't really know the process to follow.
 
Thanks.
To be honest, now that I have tried this method, I would even recommend it for anyone buying old rock, or additional rock for their aquascape, or in fact, even in older tanks where algae becomes a struggle to contain.
Its a hell of a lot cheaper than trying to clean rock with gfh in tank.
I have cooked some really dirty rock before the "old fashioned way" by copious water changes, skimming and kept in darkness, but the amount of gunk that came off and out of the rock is quite alarming in comparison.
 
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