Cooking live rock- ?'s about biology

[dbhavoc]

I'm curious about the process of "cooking" (NOT curing) rock. I'm no biologist, but as a former long-time techie slave to corporate America, I absolutely LOVE the concepts of hard resets and clean installs. As I said, I'm certainly not a biologist, so please feel free to edumacate me if I'm missing the point here.

As I understand it, the process of "cooking" dry rock is based on the principle of bacterial solubilization of inorganic phosphate. This means that the bound phosphate ions from insoluble calcium phosphate and other minerals that are created by other sequestration methods throughout the existence of the "rock" as a living organism's skeleton or later as a host to other organisms are freed. Is this about the gist of it? In this process, are the bacteria consuming the calcium and leaving phosphates as free waste?

If I understand this right, the reason for starting the process with acid/vinegar soaks is to remove as much organic material from the rock as possible. Is this done to expose the actual rock surface area as much as possible to these bacteria, or to control the growth of other bacteria that would simply continue the process of sequestering phosphate back into the rock?
My final queries are about the bacteria themselves. Are these types of bacteria commonly found outside of marine environments? It seems to me that there would be similar bacteria almost everywhere life is found, considering so many creatures are full of calcium phosphate minerals. The reason I'd like to know more is because I'm curious about wether or not saltwater is actually necessary to the cooking process. I wonder about this bacteria and wether it can survive a cooking process using ro/di water instead of saltwater. Since the rock has been dry for a long time, and successively soaked in vats of acid, is it safe to assume that these mystical phosphate munching bacteria are being introduced from outside the marine environment? If so, shouldn't it be possible to achieve the same effect in freshwater?

Anyhoo, thanks for reading my ramblings, and hopefully for shedding some more light on an interesting topic.

 

[GrahamJr]

INTERESTING OBSERVATION THREAD

A lot in my comments apply to bacteria in live rock.

I think you may find the vinegar soak has more to do with adding plenty of readily available carbon source for the bacteria to use up the accumulated phosphate in the live rock as anything in the cooking process. Cooking is probably not the best description, feeding may be a better one.

 

[HighlandReefer]

Graham Jr,

To Reef Central


Cooking live rock is more for the purpose of breaking down organic mater including dead organisms so they don't present high nutrient problems in a tank (ammonia, nitrite, nitrate and phosphate). It also services to increase bacterial populations allowing your rock to handle higher nutrient loads. The amount of phosphate used compared to the amount of nitrate is much lower, so it takes a long time to reduce Higher phosphate levels that may be bound to the rock using bacteria. Cooking rock will not necessarily kill pests in the rock including worms, pest algae, dinos, diatoms and cyanobacteria. The spore stages are quite hardy.

If you want to start fresh and make sure there are no pests in this rock then I would use a 1:10 bleach solution first to break down and kill the pest organisms that may be present. Bleach breaks down within 24 hrs, so you want to scrub and organic debris of the rock after the initial bath for 24 hrs and then repeat until the rock is clean.

After that, if there is a chance of high phosphate levels in the rock or high heavy metal content you would want to use an acid bath to remove these. You would soak the rock in a 1:10 solution of Muriatic Acid that you get from the hardware store. This will dissolve the outer layer and all exposed surfaces. If the rock is broken new surfaces are exposed, so if you want to break rocks, I would do this first. After this soak the rock in clean rodi water and you can add some baking soda to remove any acid remnants.

After that you can put this clean rock in a cycle it with some fish food for nutrients and add some vinegar for a carbon source to get new bacteria going. Bacteria are present everywhere in the world in the air and will re-populate quickly. I would use salt water to do this in. There are differences between salt water bacteria and freshwater. Some can adapt but it would need to be done very slowly or they may not survive. This is why you want salt water to get your rock going. You should get an ammonia spike and a nitrite spike at first. Then the nitrate bacteria develop and you get a nitrate spike. Once the nitrate spike is gone, you are good to introduce just a small number of fish and then increase the level slowly watching nitrate and phosphate levels as well as deadly ammonia.

 

[dbhavoc]

INTERESTING OBSERVATION THREAD

A lot in my comments apply to bacteria in live rock.

I think you may find the vinegar soak has more to do with adding plenty of readily available carbon source for the bacteria to use up the accumulated phosphate in the live rock as anything in the cooking process. Cooking is probably not the best description, feeding may be a better one.

Thanks for the link! That's a fascinating experiment. Please continue updating as you learn more. I hadn't thought of the vinegar like that. Excellent point about cooking being more like selective feeding. I've been reading through the following article to help me understand the concept behind this process, but it's very difficult to compare the floor of a natural bay to a reef aquarium biologically.

http://www.ots.ac.cr/tropiweb/attachments/volumes/vol55-1/01-Das-Biogeochemical.pdf

HighlandReefer- thanks for chiming in. It has been difficult to ascertain the goal of many hobbyists whose threads I've read. Many seem to be looking to remove pests, but a few have been interested in "revitalizing" old rock by increasing it's potential to sequester nutrients in the long term. I am interested in the biological processes involved during the "feed the solubilizing bacteria, and starve everything else" phase. Specifically, how to create a nurturing environment for them whilst maintaining a less hospitable environment for organisms that do the opposite.

 

[HighlandReefer]

HighlandReefer- thanks for chiming in. It has been difficult to ascertain the goal of many hobbyists whose threads I've read. Many seem to be looking to remove pests, but a few have been interested in "revitalizing" old rock by increasing it's potential to sequester nutrients in the long term. I am interested in the biological processes involved during the "feed the solubilizing bacteria, and starve everything else" phase. Specifically, how to create a nurturing environment for them whilst maintaining a less hospitable environment for organisms that do the opposite.

I have been constantly looking for this answer myself. :lol:

The problem is all your good reef organisms need the same nutrients at about the same levels as do the pests.

Basically pristine natural reefs have parameters around these:

phosphate: 0.005 ppm Our kits can only detect down at best to 0.01 ppm. Algae use phosphate, so this is the easiest method to reduce their growth, however many pest algae present in natural reefs survive quite well at 0.005 ppm phosphate. cyanobacteria can utilize organic phosphorous well as phosphate. Coral need some phosphate to survive as well.

Developing and maintaining a good bacterial population in a reef tank is not normally a problem unless you feed to much or have too many fish. Dosing carbon sources can overcome this if you do it properly. Otherwise you can cause problems with many of the carbon sources. Keeping good water parameters does not kill all the pests though.

Nitrate runs around 0.1-0.2 ppm. Reducing nitrate further does not seem to help when controlling the various pests.

Iron is present in our salt mixes which serves to stimulate all microbes. Eliminating iron in reef tanks is next to impossible.

So trying to get bacteria to out-compete other pests can be very difficult, if not impossible depending on the species of pest.

This leaves eliminating all pests as much as possible from your reef tank. Quarantining everything that goes in, so you don't introduce the pests in the first place. This is the reason why I don't like cooking rock.

If you decide to cook rock and keep as many good organisms as possible you need to be prepared to battle the pests that may be present. This includes a lot of scrubbing and keeping a very clean tank, including glass and sand beds. Some pests are very difficult to control, especially if you stack a lot of rock in your tank and have a lot of coral on this rock which prevents cleaning over and over again until you beat the pest. One good reason to start slow and keep new live rock in a separate tank with good lighting to make sure it has no pests and if so it makes it much easier to get rid of the pest.

Sadly one of the biggest reasons why hobbyists leave this hobby is due to problem algae, cyanobacteria and Dinoflagellates that they can't get control of and end up taking over their tank even when nitrate, phosphate are at undetectable levels. Some hobbyists reduce them so low that it kills soft corals they want to keep without controlling the pests.

Keep in mind that pests in natural reefs with good water parameters are being taken over as well throughout the world. Scientists are working on control measures to help eradicate the major algae, dino and cyano pests, but have no answers that will work in the ocean nor in reef tanks that I have seen. AlgaeFix Marine is the only algaecide labeled for aquariums, but does not kill all species of algae or cyano. So it is not an answer for everyone, but does help quite a few.

Copper will kill pests, but we have no methods to measure the extremely low levels that might kill pests and not kill coral. There seems to be a very fine line here and it is different for every species of pest.

 

[HighlandReefer]

I have not gotten into the bacteria and viruses that cause diseases in coral and fish. Sadly these diseases will survive as readily as the beneficial bacteria present. If they get into your coral or fish you got problems. You need to use quarantine systems to prevent them form taking over coral and such in your tank, including fish. How effective cooking is for particularly the coral diseases I have my doubts. The coral diseases are becoming wide spread throughout the world in some of the nicest reefs out there. Therefore when using live rock and coral taken from the ocean it is becoming more likely every day you can introduce them.

I have seen hobbyists post quite a few threads where their beautiful coral tank is wiped out by what looks to me like a disease of some sort. The symptoms are all there.

Many advance hobbyists will argue with me until one of the pests and/or diseases hits their tank. Keep in mind, that these pests and diseases have become quite a problem throughout the ocean in the last 10 years.

 

[SylvesterGraham]

I have not gotten into the bacteria and viruses that cause diseases in coral and fish. Sadly these diseases will survive as readily as the beneficial bacteria present. If they get into your coral or fish you got problems. You need to use quarantine systems to prevent them form taking over coral and such in your tank, including fish. How effective cooking is for particularly the coral diseases I have my doubts. The coral diseases are becoming wide spread throughout the world in some of the nicest reefs out there. Therefore when using live rock and coral taken from the ocean it is becoming more likely every day you can introduce them.

I have seen hobbyists post quite a few threads where their beautiful coral tank is wiped out by what looks to me like a disease of some sort. The symptoms are all there.

Many advance hobbyists will argue with me until one of the pests and/or diseases hits their tank. Keep in mind, that these pests and diseases have become quite a problem throughout the ocean in the last 10 years.

Old thread, but... What diseases are you talking about, if you don't mind my asking. And why have the become a problem just recently? (climate change?)

You mentioned earlier that rock that has been sterilized will repopulate because bacteria is present everywhere. No doubt about that, but these new colonies won't be even remotely similar to the species that occur in a wild saltwater env, species wise, am I right?

As you can see, I'm new to this. My main concerns are sustainabilty, pest control, and being able to keep a tank past "old tank syndrome". Its looking like im not going to use live rock at all, if I can find a way to build up bacteria colonies without it. What techniques do you reccomend for ridding coral frags of pests before introducing them into my tank?

 

[dan-in-gr]

Hi, I have cooked, well actually baked live rock. Last year, I got 75 lbs from a good reefer and 50 lbs from a Craigslist guy, Well part of the Craigslist guy's rock had a macro red algae that was really spreading, I tried everything - more tangs, snails, hermits, etc and no one would touch it. I took about 35 lbs of the affected rock and scrubbed it a bit and put it on a cookie sheet and baked it at 400 degrees for 20 minutes. Now it becomes "instant dry rock" free from anything living with no bacteria or pests. The stuff never grew back and am pleased with my method, simple and free.

 

[SeanT]

Originally posted by SeanT
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 do 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."
6. Saltwater, enough made up to follow the instructions below and to replenish your tank after removing rocks.
Here are the steps:

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.
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 quickly...as the water quickly turns brown.
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. Only one powerhead per tub is needed. Remember the powerheads main responsibility is the oxygenation of the water.
10. Cover the tub. Remember, we want TOTAL darkness.
11. Empty out buckets, restart circulation on main tank.
12. Wait.
13. 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 until 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.
At times the stench was so strong I gagged.

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 would say that 85% of my exposed rock had Bryopsis (hair algae) covering it.
There isn't a single visible strand on any rocks my tank 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.
Every time I do a water change they are there and plentiful.

 

[Reefin' Dude]

not sure that is what Bomber/Spanky had in mind.

the process of cooking the LR is a biological process, more than a chemical process. it is the bacteria sequestering the phosphates from the calcium carbonate binding sites, then the bacterium being removed from the area by other bacterium when they die that is removing the phosphates from the LR. it is not entirely necessary to kill everything in the system here. even the bacteria will need "food" in order to sequester the phosphates.

this is not a fast process. using acids to dissolve the outer coatings can help speed things up, but this also is like using a jack hammer when a scalpel is needed. it all depends on the aquarists patience level and how much rock they want to dissolve away.

G~