cooking live rock questions

[Linda]

I have never heard of 'cooking live rock' before. Can someone explain why this is done?
Thanks, Linda

[skeety]

Linda..


Check out some of these thread for the answer to your qeustion:

http://www.thereeftank.com/forums/sh...t=Cooking+Rock
(around post 10-11, you'll get your answer)

http://www.thereeftank.com/forums/sh...t=Cooking+Rock

http://www.thereeftank.com/forums/sh...t=Cooking+Rock

that should give you enough.

[Geoff]

"Cooking" LR is a way to remove phosphates from the LR. over time LR absorbs phosphates like a sponge. eventually it fills up. at this point you start to see HA and cyano growing on it. the most common way the LR gets full is resting on top of a substrate. LR actually wicks up the phosphates from the substrate when it gets full. the whole process works it way up the aquascaping until all of the LR is phosphate laden. usually by this time the aquarist has given up due to a HA problem that will not go away.

what "cooking" involves is washing a scrubbing the LR in clean SW to remove any large portions of algae that have started growing on them. they are then placed in a tank/tub without any substrate. putting it up on a stand is even better. you will run this tank like this for at least a month. running this like a tank. climate control, skimming, and water top-off. you do not want light, it works faster in the dark. every week when you do water changes on this tank, you want to siphon out all detritus that has fallen out of the LR. the easiest way to know when it is done is when there is not any more detritus falling out of the LR. it is also a good idea to swish/turkey baste them when doing water changes to get the detritus that gets pushed out to the top of the LR.

this detritus is bound up phosphates in bacterial flock. when the bacteria die the living bacteria push it out using turgor until it falls to the bottom of the tank. due to the size of bacteria the process works all throughout the LR.

this is generally not a fun thing to do. this is why i am always suggesting BB tanks for almost all aquarium types. this allows easy removal of the detritus before it is able to build up in the LR.

G~

[Linda]

k, thanks!

[Linda]

I've only had the live rock for about a year, or less. When does this happen, if it's going to, and what do I look for?
Thanks in advance.
L.

[reef_noob]

Originally Posted by Linda

I've only had the live rock for about a year, or less. When does this happen, if it's going to, and what do I look for?
Thanks in advance.
L.

Massive uncontrollable hair algae outbreaks are the most common sign. Of course, with proper husbandry, this can be avoided for the most part.

[skeety]

check out THIS thread...which discusses life of the Live Rock. interesting

http://www.thereeftank.com/forums/sh...ad.php?t=60417

[Geoff]

Originally Posted by Linda

I've only had the live rock for about a year, or less. When does this happen, if it's going to, and what do I look for?
Thanks in advance.
L.

if you feed the tank a lot and you do not siphon out detritus it is not inconceivable that it could happen within a year.

there are a lot of factors that influence this. depth of sandbed is also a factor.

G~

[Kevin1000]

Geoff ... nice concise explanation .. sure beats going though some of those monster threads over a RC.

I think I understand the basic concept of live rock cooking ... however I am a bit confused on the phosphate wicking thing ... not sure how that works .. are you implying that phosphate loaded detrius is moving from the substrate into the live rock or that phosphates themselves are moving into the rock .. if so .. hows that work and why would they move into the LR vs the water column?

[Geoff]

Originally Posted by Kevin1000

Geoff ... nice concise explanation .. sure beats going though some of those monster threads over a RC.

I think I understand the basic concept of live rock cooking ... however I am a bit confused on the phosphate wicking thing ... not sure how that works .. are you implying that phosphate loaded detrius is moving from the substrate into the live rock or that phosphates themselves are moving into the rock .. if so .. hows that work and why would they move into the LR vs the water column?

thanks, i try and be the layman exlainer.

i also hate trying to dredge through some of those crazy threads. it would not bother me so much if there was not all of the extraineous stuff that occurs.

i do not know the exact mechanisms that cause this, maybe Tom will pipe in

it is the phosphates themselves that are being wicked up into the LR. the calcium carbonate that makes up both the substrates we use and the LR itself is porous to phosphates. it is much more porous to phosphates than the water column. this is why the phosphates can be in the system and not show up on the test kits (this statement can also get more complicated because of the different types of phosphates, i also do not know all of these mechanisms).

G~

[tdwyatt]

Hmmm...


Not so sure that actual "wicking" occurs in the way that would occur when phosphate ions go from one sinked compartment to another via capillary action: there are a lot of kinetics involved in having the phosphates de-adsorb, develop a differential in terms of concentration, then readsorb to the live rock after moving due to some form of capillary action within the rock. Surface area in the rock as opposed to the sand bed should not be an issue, however the bacterial activity of the rock might be such that the rock has more capacity for capture of whatever free inorganic phosphate (an likely that some of the organic forms as well) is available in the water column. I do not see "wicking" occurring in the classical sense of the physics of capillary action, as the bacteria in the sand bed are retty selfish about giving up whatever nutrient they can capture from the biofilm ecologies of the sand gruanues. However, if detritus is allowed to collect on flat surfaces of the rock as intra-rock turgor drives it out, then I see this as a more likely cause of phosphate-related issues rather than a transport via "free" ionic concentration differences between the sand compartment of such a model and the rock compartment. Although in systems with heavy fish populations and poor husbandry, heavy feeding, and poor export, there could be a quick accumulation of phosphate, the mere presence of green microalgae or cyanobacteria is not necessarily a sign that the rock definitely has saturated with phosphate. However, the presence of persistant, difficult to control blooms should be a warning sign that there are nutrient contol issues. It doesn't mean you should tear your tank down and start the phosphate purging process (cooking the rock), but it does mean that you'd better get your nutrient control and export processes in order to prevent saturation from occurring.

see: http://www.thereeftank.com/forums/sh...ad.php?t=60417 this post.

I hate to see folks get discuoraged due to the presence of algae, but when it shows up, it is a signal to get busy before the tank DOES have major issues in nutrient and algal control.


HTH

[Kevin1000]

Tom ... thanks for your input.

I don't have the stamina to make my way through all of the monster threads on this subject --- it is my impression that Bomber/Spanky initially described a process of curing live rock which helped insure that the excess nutrients on/within live rock were removed from the rock/tank rather than made available to nuisance algaes --- this concept (which made alot of sense to me) seemed to evolve into a concept where any live rock with a hair algae issue must be loaded with phosphates and/or your sand bed must be overfilled with phosphates ... both may be true but, if so, the dots connecting that logic are alot less clear to me than others.

[tdwyatt]

Originally Posted by Kevin1000

Spanky initially described a process of curing live rock which helped insure that the excess nutrients on/within live rock were removed from the rock/tank rather than made available to nuisance algae --- this concept (which made a lot of sense to me) seemed to evolve into a concept where any live rock with a hair algae issue must be loaded with phosphates and/or your sand bed must be overfilled with phosphates ... both may be true but, if so, the dots connecting that logic are a lot less clear to me than others.

I think the issue is causality for the appearance of hair algae/nuisance algal growths related to whether or not the rock/sand is saturated with phosphates: this is not necessarily true 100% of the time, and is probably not true in most situations.


Just because you see these nuisance algae growing in the tank does not mean the rock and/or sand has become saturated with nutrients, it only means that there are sufficient amounts of free phosphate available in the system that the algae no longer are growth-limited by phosphate. The limiting nutrient then becomes nitrate, just as it does in the ocean. The problem in closed systems is that there is generally an accumulation of phosphates to the point that phosphate is readily available in a ready-to-use form almost all the time, and if the substance is not exported from the system, it WILL reach a point at which the rock and any sand or other calcareous substrates reach some maximum level of saturation, acting as a continuous source of phosphate as any organisms in the water column use it up. Think of this water column activity as a savings account for phosphate. The bank in our analogy would be any substrate in the tank that contains calcium (rock and sand). Feeding the tank will allow for an initial deposit to the bank, but the account grows interest as any leftover organics that contain Phosphate (the currency of the "First Bank of Algae") decompose to release their phosphates into the water column. This particular bank has the ability to take a fee (as high as 30%) from any transaction (phosphate-related reactions) that occurs in its place of business (the water column) and place it in the vault (the rock or sand bed). The algae, bacteria, and to some extent, the benthic infauna and fishes of the system are the general public, they are spending and making money (losing and gaining phosphate) with their checking accounts, saving accounts, and occasionally with cash. Each transaction they perform with the bank will have some impact on the amount of money (phosphate) in the bank's vaults (sand and rock), but only occasionally do we actually see money in the bank (the water column). Not all transactions occur in the bank, but a good number of them do, as cash transactions (those phosphate movements in the water column as inorganic phosphate) only occur rarely. Just because we do not see the money in the bank, does not mean that the stimulus to the local economy does not occur (general life forces in the tank, including algal growth), as IF the local economy starts to slow, so long as there is money in the bank, local businesses (algae) will be able to borrow money (Phosphate) from the bank (sand bed or live rock) to keep the economy running (patchy algal outbreaks). This is not to say that the bank has its vaults full of cash, rather that it has enough there (as detritus) to keep the local economy running without dipping into its reserves (sand bed, live rock) too often. Ideally, to prevent a robbery (algal bloom), the federal reserve (aquarist) will take deposits from the bank (export phosphates) or tighten the money supply (siphon detritus) to reduce the chance that an economic disaster like runaway inflation might occur (eutrophic tank crash). However, even though there is an outside chance that an economic slowdown may occur (phosphate limitation of coral growth), it is unlikely due to the nature of the strong business environment (readily available phosphates from feedings, etc.).


This analogy works to a limited extent to explain the processes involved with calcium-based substrates in a marine closed system, and yes, there is an IRS for this analogy (chemical adsorbents like GFH and carbon) that is capable of taking money (phosphates) from all segments of the economy, and like the real-life version of this bedtime story, it does not squander it on porkbarrel unless left untended...



The upshot is, just because there is a presence of algae in a system does not mean the rock is saturated, or that problem algal blooms = you must "cook"/purge the rock. Algal growth is a normal biological activity in a balanced system. With adequate export and good husbandry, coupled with adequate herbivory, your system will function as it is intended to. The biggest issue with nutrients and closed marine systems is for those that desire to keep the more exotically colored corals at their peak of coloration, and nutrient control is not the only issue under those circumstances.




HTH

[Kevin1000]

Thanks Tom ... great explanation.