Are Deep Sand Beds, DSBs, dangerous to use in a marine aquarium?

[Fredfish]

back to the hamburger example.

that waste from the other organism can be a food for another organism, but like you said no organism is 100% efficient. it is also going to produce waste. what is feeding all of this biomass?

Waste.

Look at it this way. You toss a hamburger into the tank, your fish eat it and poop out 80% as undigested organic matter. The sand bed critters eat that remaining .8 of a burger and poop out .64 of a hamburger. That .64 of a hamburger gets consumed again and .51 of a burger is pooped out. .51 of a burger is consumed again and .4 is pooped out. Only 10 times through and you only have a bite (10%) left. It's an orgy of pooped out hamburger gorging until there is nothing left.

That is why you want a healthy benthic community in your tank.

That is why you do not want to stir your sand bed, in effect grinding up all those beneficial organisms and turning them into a nutrient source instead of a source of nutrient consumption.

 

[asylumdown]

are you still growing in mass? at least in a healthy way? no organism is 100% efficient. all of the material we bring in is not incorporated into our structure. the rest is discarded. if this were not the case then we would keep growing indefinitely. organisms are constantly moving material in and out of themselves.

No of course not, but using an adult vertebrate is an inappropriate analogy. Macro algae most certainly is increasing in mass. If it is not increasing in mass, it is dying. In fact under the right conditions, it can increase in mass rather rapidly. While at any one moment it may look like you have a fairly constant mass of macro algae in a refugium, if one were to save all the material that was harvested for export over the course of the year and weigh it, you would find that you had permanently removed a considerably amount of nitrogen and phosphorous from your system

ecosystem and diversity are just fancy words for phosphates sinks, which is a fancy word for cesspool.

G~

The more I read your posts, the more I think that your ideal aquarium is an empty glass box. In one sentence you've compared basically the entire point and foundation of keeping an aquarium to a storage container for sewage.

 

[Nano sapiens]

What I see here is aquarists coming at this topic from different angles with different objectives. Looking at the extremes:

Person 'A' wants to emulate an ocean reef's oligotrophic water. To keep Acropora and similar corals in such an environment, they need to be fed a relatively large amount and variety of high quality foods. Obviously, to maintain these pristine water conditions, nutrient export needs to be very efficient and removal of uneaten food/detritus as soon as possible, before it breaks down, is a top priority. This person is not concerned with 'all the little critters' in this case, since the focus is on the corals.

Person 'B' wants to have as complete an ecosystem as possible. He finds delight in seeing all the worms, crustaceans, etc. moving around the tank looking for tidbits to eat. He wouldn't dream of vacuuming up these creatures and throwing them out. Fish, coral and other creatures complete this little ecosystem and he's happy to let all the small benthic animals chow through the detritus until it's been turned to near inert mulm.

IMO, there is no 'right' or 'wrong' here, just 'different' as long as the tank maintains the desired level of eutrophication that the reef keeper finds acceptable and the system can effectively deal with. Problems result when the degree of eutrophication becomes damaging to the life forms we are trying to keep and the system as a whole becomes unbalanced.

 

[asylumdown]

One thing I am consistently seeing in this thread is an inappropriate use of the term 'eutrophication'. Eutrophication in environmental science describes the input of excess simple nutrients like nitrate and phosphate beyond the capacity for complex benthic autotrophs like vascular plants to absorb it, shifting the ecosystem towards simple, single celled benthic algae.

If that were happening in your tank, it would be quite obvious and your tank would be quite dead.

"oligotrophic" only describes the water around coral reefs, not the coral reef system as a whole. About the only thing that can live in truly oligotrophic aquatic systems are biofilms of cyano bacteria.

More material transitioning through a trophic web does not de-facto equal eutrophication. Coral reefs have very low dissolved nutrients in the water, but insanely high quantities of nutrients bound up in the tissues of the millions of things that live on them, with very efficient pathways to recycle them. Ditto for rain forests - they have some of the poorest soils in the world because all the nutrients are locked up in the biomass growing above them, but if you looked at just the soil then called the system nutrient poor you'd be kind of missing the point. You can have all the nutrients in the world in your system, but if they're bound up in the living tissues of a desirable benthic trophic web and not dissolved in the water causing damage to corals or fuelling the growth of copious amounts of unwanted algae, you do not have a eutrophic system.

It is absolutely possible to maintain oligotrophic-like water in an aquarium with a large biomass, a "complete" trophic web, and large inputs of material. Thousands of people do it in their tanks, and coral reefs have been doing it for hundreds of millions of years.

 

[Nano sapiens]

Eutrophication (Merriam): the process by which a body of water becomes enriched in dissolved nutrients (as phosphates) that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen.

Obviously, if a system reaches the stage of oxygen depletion, then yes the sytem is kaput. Eutrophication is a process and that implies levels and stages (even if they are not formally defined), so I don't consider it an inappropriate term in this circumstance. But you can substitute 'degradation', if you like.

"Person 'A' wants to emulate an ocean reef's oligotrophic water."

Correct, oligatrophic refers to the water, not the system as a whole and that is what I said. Perhaps you are referring to other posts that do not realize the correct use of the term.

"It is absolutely possible to maintain oligotrophic-like water in an aquarium with a large biomass, a "complete" trophic web, and large inputs of material. Thousands of people do it in their tanks, and coral reefs have been doing it for hundreds of millions of years."

Agreed, if the waste material is either removed frequently and/or processed effectively then the sustained biomass in a system can be quite substantial. Of course, there are limits to what a system can handle and what is being debated here is mainly how long a DSB will operate without degrading the system to the point of failure (assuming it will at all). Some say 5 years, others 10 and some say it'll function properly for as long as the aquarist has the tank set up. So, in my mind, there is no straight answer since each system's set of variables are unique.

 

[tmz]

A few points to clear up.

There are too many opinions posing as fact throughout the thread as it jumps from hamburgers to terrestrial soil based solubilizing bacteria and crosses several geological eras in time.
The hobbyist that participate on RC are not ignorant of the role and behavior of phosphate IME ;most of the folks responding on this thread are knowlegeable about it,one in particular has extraordinary expertise in it's biological role . Most understand how organisms use it and understand the differnce between miscibility and gravity, refractroy and non refractroy organics ,the imprortance of nutreiont balance including nitrogen and reactive and sunk phosphate.

The papers repeatedly cited make no case at all to support a notion that mineralized phosphate sunk in substrate is solubilized in any significant qauntity in a reef tank. Indeed some of them point in the opposite direction as I noted in earlier posts . Solubilizing bacteria that would thrive in a reef tank are repeatedly noted in several posts as major players but not identified.
The pictures , choosen use a mangrove swamp to illustrate the phosphate cylce, an environment subject to frequent and large salinity shifts, fine sediments, high incidents of anoxia, copious amounts of organic matter ,acidified water, and of course rhizome activity all of which would likely support more dissolution of precipitants than would occur in a reef tank,imo. Even then no volume estimates are made.
The broad extrapolations drawn from agriculture, sewage treatment , hamburgers,terrestial upheavals ,deep sea enviromnets etc don't really bring the hobby forward as they are presented throughout but rather resemble a bunch of uncconected dots with extrapolations leaping from one to the other at will absent any clear focus on conditions in an actual reef tank.

It is absolutely possible to maintain oligotrophic-like water in an aquarium with a large biomass, a "complete" trophic web, and large inputs of materi

FWIW, I have done exaclty that for the last 5.5 years. PO4 .02 to .04ppm/NO3 0.2ppm , Feeding well over 2.5 ounces of frozen foods daily plus others . Without heavy reliance on deep sand and no gfo for the last 8months.

 

[tmz]

Carbon dosing does very little to remove P compared to other export methods because it removes it in Redfield proportion as organism export in a ratio of ~100:1 C, and our systems are not well set up to remove the basal plankton and prokaryotes that are the primary utilizers of dosed carbon

That has not been my experience,Pi reduction and maintenance at low levels are quite evident even with out gfo or other removes or filter media, IME. Do you have data on that beyond the extropoation from the redfied ratio. Not sure I'd assume the bacteria conform to redfield levels Not sure which basal plankton and prokayotes you mean but if you idientified them it would be helpful.Anyway this thread is about "dangerous ?" sand beds

 

[asylumdown]

Sorry that wasn't in response to you specifically, you were just the last one to use it and that made me think of it lol. If it came off like I was attacking you specifically I do apologize. My comment was a general response to the tossing about of a sciencey sounding scary word that doesn't actually describe what is taking place in a marine aquarium that's not basically on the verge of a major crash. It's been repeated a few times in this thread that sand beds, or any medium within which detritus and organic matter can accumulate/phosphate can bind to encourage 'eutrophication' of a system. That's just not an accurate use of the term. An increase in total mass maybe, but that's not the same as 'eutrophication'.

Eutrophication (Merriam): the process by which a body of water becomes enriched in dissolved nutrients (as phosphates) that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen.

Obviously, if a system reaches the stage of oxygen depletion, then yes the sytem is kaput. Eutrophication is a process and that implies levels and stages (even if they are not formally defined), so I don't consider it an inappropriate term in this circumstance. But you can substitute 'degradation', if you like.

Another key point is that "eutrophication" is a relative process. IE, it can only be said to be occurring when nutrients that were previously limiting are now being added in excess, thus shifting the state of the system. It's also typically accompanied by a very specific set 'symptoms', namely a shift in species composition (usually a decrease in diversity as a few aggressive species capitalize on the excess nutrients to the detriment of others), and often an increase in toxic allopathic chemicals produced by single celled algae and cyanobacteria. Such events definitely happen in tanks, but if that were happening, you'd definitely notice.

"Person 'A' wants to emulate an ocean reef's oligotrophic water."

Correct, oligatrophic refers to the water, not the system as a whole and that is what I said. Perhaps you are referring to other posts that do not realize the correct use of the term.

"It is absolutely possible to maintain oligotrophic-like water in an aquarium with a large biomass, a "complete" trophic web, and large inputs of material. Thousands of people do it in their tanks, and coral reefs have been doing it for hundreds of millions of years."

Agreed, if the waste material is either removed frequently and/or processed effectively then the sustained biomass in a system can be quite substantial. Of course, there are limits to what a system can handle and what is being debated here is mainly how long a DSB will operate without degrading the system to the point of failure (assuming it will at all). Some say 5 years, others 10 and some say it'll function properly for as long as the aquarist has the tank set up. So, in my mind, there is no straight answer since each system's set of variables are unique.

I would agree with you here. Material that goes in eventually must come out, and there are myriad ways of accomplishing that. I've said it before but I'll say it again, I've got no issue with the 'issue' with deep sand beds in general, I just don't think this particular 'issue' with deep sand beds is the right one to have

None of the factors that supposedly go in to making a deep sand bed 'function' or 'fail' are testable, or even really all that modifiable by the aquarist. Supposedly a complex web of micro-fauna plays a large role in their success - no one has any idea which micro-fauna though. Have you ever seen a list of published worms, pods, and other critters that must be present for a sand bed to function the way people think it does? Are there keystone species that must be present, or just ecological niches that must be filled? Is the species composition important? Are there faunal assemblages that are more or less efficient than others? Are there minimum size requirements to maintain stable populations over time? Is it stable over time, or is there drift and how does that affect nutrient cycling through the system? If nature is to be our guide, both the starting conditions (i.e., what organisms your tank is exposed to), the animals you keep, the rocks you have, the amount you feed, the kinds of food that go in, the fish you keep, the size of your system, etc. etc. etc. will all affect the 'ecology' that develops in your sand bed, usually in ways you can't predict, and certainly in ways that will change over time. Even if we knew all of the above, is any of that even possible to intentionally influence as an aquarist? What happens if there's a stocking threshold above which a deep sand bed's fundamental function as a nutrient processing device shifts in the negative, but it takes 8 months for the consequences of that shift to present themselves? An aquarist who hasn't added a fish in 6 months could be very confused when all of a sudden their sand bed turned in to an anoxic, sulphide belching monster and might blame the method simply because they have no understanding of what actually happened.

Just tossing in a handful of someone else's sand and hoping for the best seems pretty weak sauce when so much is expected out of a sand-bed's performance.

No one's ever compared a deep sand bed that has been successfully operating for years to decades with a deep sand bed from a system with nothing but problems from a micro and near micro-biological perspective, so we really have no idea why they work when they do or why they don't when they don't. We tell ourselves stories about them that scratches that itch to capture the incomprehensible magic a living ecosystem that all aquarists seem to have, but by and large that's just a story we tell ourselves to make us feel better. We actually have no idea what's going on.

 

[tmz]

Cleaning sand beds or hands off.
I think the aversion to disturbing a bed comes from an early idea that the bacteria involved in dentrification would perish in the presence of oxygen that would disturb hypoxic areas where anaerobic activity was occurring and concern about disturbing pocketts of hydrogen sulfide. Maybe some worry about microfuana. The bacteria are faucltative.

Anecdotally , I do accept that leaving a bed undisturbed with a healthy population of sand fauna can work in some tanks as many report it does for long periods of time but I never got the effects I wanted that way and the choice of sand critters remains puzzling to me.

Personally, I've had good effects from puffing up and/or vacuuming the top inch or so of sand and leaving the deeper areas unstirred;not much gets down there anyway,ime. Never could understand why cleaning up the top was any different than employing sea cucumbers or other sand sifters in terms of sand bed disturbance.

 

[tmz]

My cuke works great for that, but I like to wash off the oil and vinnegar first.

Hi Paul, great color. Did it get nuclear green form feasting on that LI sound mud?
The more threads like this I read ,the more I'm tempted to try out rugf or some variant of it.

 

[Nano sapiens]

We actually have no idea what's going on.

When all is said and done...that just about sums it up

At least we know a bit more than we did 20 years ago, but we still have a ways to go...

 

[asylumdown]

When all is said and done...that just about sums it up

At least we know a bit more than we did 20 years ago, but we still have a ways to go...

I personally like it this way. Not knowing means there's still questions to ask and answers to find. If I were independently wealthy I'd build a lab and spend the next 20 years just testing all the (sometimes ridiculous) ideas people have about what's going on in a tank. It's all testable, literally all of it. It just takes time, equipment, and money.

This phosphate question would be fun to answer in a lab set up. I can think of at least a dozen different experimental set-ups to answer a dozen different specific questions relating to phosphate, rock, and sand beds.

We seem to limp along as a hobby making accidental advancements in fits and spurts through aggregations of anecdote and analogy. In lieu of a multi-million dollar marine research lab dedicated to my own hobby, I suppose that will have to do.

 

[tmz]

confused. this graph is of the marine environment, ....done by bacterial activity. the same activity that allows "cooking" of LR. the phosphate solubilizing bacteria are doing this.

The graph is of a mangrove swamp. Acidification and other process are just as likely to cause dissolution at more significant levels there than a reef tank than some unidentified solubilizing bacteria may or /may not.

"cooking", purging, or curing LR utilize this process.

Mineralization or breakdown to refractory organics /aka sinking phosphate seem more likely, imo.
"Cooking" usually means leaving the rock in a darkened bin of water for a year or so .I think it may work as a result of bacterial degradation and mineralization ,sinking the phosphate and other elements in refractory organics or via mineralization. If it is a process that simply liberates the phosphate as you suggest via unidentified solubilizing bacteria with no export then where do you suppose the phosphate goes in the end?

 

[tmz]

What I see here is aquarists coming at this topic from different angles with different objectives. Looking at the extremes:

Person 'A' wants to emulate an ocean reef's oligotrophic water. To keep Acropora and similar corals in such an environment, they need to be fed a relatively large amount and variety of high quality foods. Obviously, to maintain these pristine water conditions, nutrient export needs to be very efficient and removal of uneaten food/detritus as soon as possible, before it breaks down, is a top priority. This person is not concerned with 'all the little critters' in this case, since the focus is on the corals.

Person 'B' wants to have as complete an ecosystem as possible. He finds delight in seeing all the worms, crustaceans, etc. moving around the tank looking for tidbits to eat. He wouldn't dream of vacuuming up these creatures and throwing them out. Fish, coral and other creatures complete this little ecosystem and he's happy to let all the small benthic animals chow through the detritus until it's been turned to near inert mulm.

IMO, there is no 'right' or 'wrong' here, just 'different' as long as the tank maintains the desired level of eutrophication that the reef keeper finds acceptable and the system can effectively deal with. Problems result when the degree of eutrophication becomes damaging to the life forms we are trying to keep and the system as a whole becomes unbalanced.

I agree there is no right or wrong to an overall approach or specific methods. I do think,however, it's possible to have both A and B with a lot of circulating zooplankton and larvae and other organic foods for corals to meet their heterotrophic needs along with oligotrophic water. A well managed sand bed could be one contributor in such a system .Various refugia with or without sand or organic carbon dosing are others.

 

[Amphiprionocellaris]

None of the factors that supposedly go in to making a deep sand bed 'function' or 'fail' are testable, or even really all that modifiable by the aquarist. Supposedly a complex web of micro-fauna plays a large role in their success - no one has any idea which micro-fauna though. Have you ever seen a list of published worms, pods, and other critters that must be present for a sand bed to function the way people think it does? Are there keystone species that must be present, or just ecological niches that must be filled? Is the species composition important? Are there faunal assemblages that are more or less efficient than others? Are there minimum size requirements to maintain stable populations over time? Is it stable over time, or is there drift and how does that affect nutrient cycling through the system? If nature is to be our guide, both the starting conditions (i.e., what organisms your tank is exposed to), the animals you keep, the rocks you have, the amount you feed, the kinds of food that go in, the fish you keep, the size of your system, etc. etc. etc. will all affect the 'ecology' that develops in your sand bed, usually in ways you can't predict, and certainly in ways that will change over time. Even if we knew all of the above, is any of that even possible to intentionally influence as an aquarist? What happens if there's a stocking threshold above which a deep sand bed's fundamental function as a nutrient processing device shifts in the negative, but it takes 8 months for the consequences of that shift to present themselves? An aquarist who hasn't added a fish in 6 months could be very confused when all of a sudden their sand bed turned in to an anoxic, sulphide belching monster and might blame the method simply because they have no understanding of what actually happened.

You pretty much summed up the focus of my dissertation in one paragraph, though I would argue that many of those are testable, just very difficult to do so in a controlled fashion in a fully functioning reef system with hundreds (if not more) of interactions happening simultaneously. A big part of what I do is computational/modeling work, which allows us to address that, but there's still a massive (hopefully, career-sustaining...) list of questions to address.

I can at least answer a few of those questions: the main maco organisms in the tank that matter in the sand bed are amphipods, medusa/spaghetti worms, various polychaetes especially bristle worms. It appears from my and others' research that the two most important things in terms of nutrient cycling are density of organisms and functional diversity (which is *perhaps* why multiple sand beds with different communities still do the same net processes). Perhaps surprisingly, hundreds of different combinations can yield the same results, and there is indeed community drift but it appears not to matter in terms of nitrogen cycling (I can only comment on N, because that's what my research is...it's probably similar for P); because the macro-organisms are more than anything facilitators and mediators for the microbes that actually do the stuff (and that are much more uniformly distributed), it makes sense that you can arrive at the same big picture through a variety of ways.

Of course that's just scratching the tip of the iceberg, and this is stuff that benthic ecology as a whole is just now starting to take into consideration in detail, and the past five years maybe have seen a massive shift in how we think of marine sediments. In many ways, the hobby has actually been out in front of mainstream science on this (given that the immediate stakes are a little higher for us). But as you said, we start adding layers and layers of variables whose effects we simply don't know, which is one reason (even if the funding were available, which is another story) it's really, really difficult to design direct empirical studies to test these things consistently. That said, we do have a framework of the general way things work, even if we're still filling in a lot of the details.

I know that still leaves a lot of questions open about the details of macrofauna in the sand bed, but we're at the edge of knowledge on that one.

 

[Amphiprionocellaris]

Cleaning sand beds or hands off.
I think the aversion to disturbing a bed comes from an early idea that the bacteria involved in dentrification would perish in the presence of oxygen that would disturb hypoxic areas where anaerobic activity was occurring and concern about disturbing pocketts of hydrogen sulfide. Maybe some worry about microfuana. The bacteria are faucltative.
.

Personally, I advocate against disturbing a sand bed out of concern for the fauna themselves, given how important they are in my particular approach to reefing. I don't think anyone really knows what effect vacuuming would have on them, but I err on the side of caution. I think there's also something there about stirring up pockets of reduced substances which would then draw down oxygen levels, but that's also speculative until more research is done.

 

[Reefin' Dude]

What I see here is aquarists coming at this topic from different angles with different objectives. Looking at the extremes:

Person 'A' wants to emulate an ocean reef's oligotrophic water. To keep Acropora and similar corals in such an environment, they need to be fed a relatively large amount and variety of high quality foods. Obviously, to maintain these pristine water conditions, nutrient export needs to be very efficient and removal of uneaten food/detritus as soon as possible, before it breaks down, is a top priority. This person is not concerned with 'all the little critters' in this case, since the focus is on the corals.

Person 'B' wants to have as complete an ecosystem as possible. He finds delight in seeing all the worms, crustaceans, etc. moving around the tank looking for tidbits to eat. He wouldn't dream of vacuuming up these creatures and throwing them out. Fish, coral and other creatures complete this little ecosystem and he's happy to let all the small benthic animals chow through the detritus until it's been turned to near inert mulm.

IMO, there is no 'right' or 'wrong' here, just 'different' as long as the tank maintains the desired level of eutrophication that the reef keeper finds acceptable and the system can effectively deal with. Problems result when the degree of eutrophication becomes damaging to the life forms we are trying to keep and the system as a whole becomes unbalanced.

i thought i have been making this clear throughout this thread. i have mentioned many times that the amount of nutrient export needs to match the trophic level of the system wanting to be emulated. a substrate makes perfect sense in those systems maintaining those organism from more eutrophic areas. a system without a substrate and emphasis detrital removal makes more sense for those emulating the more oligotrophic area. there of course is some leeway, but the more you stray form the more resources that will be necessary to maintain the desired trophic state. resins, carbon dosing, GFO are all masking the affects of eutrophication by going after the iP in the water column.

confused. this graph is of the marine environment, ....done by bacterial activity. the same activity that allows "cooking" of LR. the phosphate solubilizing bacteria are doing this.

The graph is of a mangrove swamp. Acidification and other process are just as likely to cause dissolution at more significant levels there than a reef tank than some unidentified solubilizing bacteria may or /may not.

and what causes this acidification? what causes the pH to drop? i give you hint. look up decomposition of organic material and what is one of its by products.

"cooking", purging, or curing LR utilize this process.

Mineralization or breakdown to refractory organics /aka sinking phosphate seem more likely, imo.
"Cooking" usually means leaving the rock in a darkened bin of water for a year or so .I think it may work as a result of bacterial degradation and mineralization ,sinking the phosphate and other elements in refractory organics or via mineralization. If it is a process that simply liberates the phosphate as you suggest via unidentified solubilizing bacteria with no export then where do you suppose the phosphate goes in the end?

it becomes the detritus you see at the bottom of the tank in which you are "cooking" the LR in. what else do you think that detritus is comprised of?

Waste.

Look at it this way. You toss a hamburger into the tank, your fish eat it and poop out 80% as undigested organic matter. The sand bed critters eat that remaining .8 of a burger and poop out .64 of a hamburger. That .64 of a hamburger gets consumed again and .51 of a burger is pooped out. .51 of a burger is consumed again and .4 is pooped out. Only 10 times through and you only have a bite (10%) left. It's an orgy of pooped out hamburger gorging until there is nothing left.

That is why you want a healthy benthic community in your tank.

That is why you do not want to stir your sand bed, in effect grinding up all those beneficial organisms and turning them into a nutrient source instead of a source of nutrient consumption.

no offense, but you really do not understand the basics of a biological system. please look at how a sewage treatment plant operates because i have a feeling you feel that they also perform magic and are also able to make P vanish.

in your example all of your organisms are operating at higher than 100% efficiency. i would wish this were true. if what you say were true, then that ONE organism must increase its mass by the amount of material taken up by the material taken in that is not expelled. that would mean that that ONE organism would be quite large and getting bigger. for every ONE organism you add you must also add in the amount of food and waste created.

lets look at your example more closely.

Look at it this way. You toss a hamburger into the tank, your fish eat it and poop out 80% as undigested organic matter.

so that ONE organism is increasing at a rate of 20% of its incoming nutrients. for every meal that ONE organism is increasing in it mass. are you increasing in your mass at a rate of 20% of the mass of your incoming food?

The sand bed critters here is your problem. you can not lump them together that way. you need to look at the individual organism. for every mouth you add, you add that organisms waste. for that one additional organism that is alive, you must have food for that organisms, or it would not be alive. eat that remaining .8 of a burger and poop out .64 of a hamburger. That .64 of a hamburger gets consumed again and .51 of a burger is pooped out. .51 of a burger is consumed again and .4 is pooped out. Only 10 times through and you only have a bite (10%) left. It's an orgy of pooped out hamburger gorging until there is nothing left. there can not be nothing left. that is the problem and i think that is where you are missing what P can and can not do. P has to be exported in order for it to leave the system. whether or not it is in an organism, in the new food coming into the system, or in the waste organic material in, it is still IN THE SYSTEM. all of those extra organisms are telling you this.

That is why you want a healthy benthic community in your tank. and that is why biodiversity and ecosystem are fancy words for phosphate sinks (cesspool)

That is why you do not want to stir your sand bed, in effect grinding up all those beneficial organisms and turning them into a nutrient source instead of a source of nutrient consumption. that is why i suggest siphoning up all of that waste organic material and those pesky benthic organisms and export all of that P

did you understand my hamburger example earlier about the amount of hamburgers go through an organism in a given period? all of the resources needed for an organism to survive must be available in order for the organism to survive.

Personally, I advocate against disturbing a sand bed out of concern for the fauna themselves, given how important they are in my particular approach to reefing. I don't think anyone really knows what effect vacuuming would have on them, but I err on the side of caution. I think there's also something there about stirring up pockets of reduced substances which would then draw down oxygen levels, but that's also speculative until more research is done.

if the system is wanting to be more eutrophic, then absolutely keep the benthic organisms, or if you really like them around. that is the your purpose. the problem i have is that all of these organisms are not doing anything to help maintain the trophic state of an oligotrophic system.

this happen to the benthic organisms if one were to siphon the substrate on a regular basis. they would be siphoned up and removed along with the waste organic material that is at the bottom of the bucket. as the waste organics start building up again in the substrate, they will again repopulate. this is no different that what happens when someone starts up a new system.

--------------------------

i want to clarify what i am suggesting about nutrient exports. i am not saying that detritus removal is the only way to remove P. i think that it should be made primary instead of tertiary. the way the marine hobby goes about P removal is more top down. i am just suggesting from the bottom up, that is all. i suggest using detritus removal by water changes as primary, with a heavy dose of skimming. if that is also not adequate then use resins, GFO, carbon dosing if needed. all of this is of course matched to the trophic state wishing to be emulated. adjust the skimming, the feeding, the siphoning, etc..... to maintain that particular trophic state. the way it is done now is the opposite. the only time detritus removal seems to be recommended is when the system has become so eutrophic that the only recourse is to start over. why does starting over help if it is not bringing the system back to as low of an initial P as possible?

i wanted to post some information about decomposition and fertilizers.

Chapter 2. Organic matter decomposition and the soil food web
Chapter 1, The Decomposition Process
The Major Biogeochemical Cycles and Their Interactions

note the production of CO2 by the microorganism.

The Best Animal Manure Fertilizers

quote from above link:

"The best animal manure fertilizers come from livestock, fish, worms and even bats."

which of those organisms are in our system?

Fish-Waste Composting

G~

 

[tmz]

Quote:
<table cellpadding="5" cellspacing="0" border="0" width="100%"> <tbody><tr> <td class="alt2" style="border:1px inset"> Originally Posted by tmz
confused. this graph is of the marine environment, ....done by bacterial activity. the same activity that allows "cooking" of LR. the phosphate solubilizing bacteria are doing this.

The graph is of a mangrove swamp. Acidification and other process are just as likely to cause dissolution at more significant levels there than a reef tank than some unidentified solubilizing bacteria may or /may not.
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and what causes this acidification? what causes the pH to drop? i give you hint. look up decomposition of organic material and what is one of its by products

skipping from dot to dot again. You obviously don't get the differnece between solubilizing bacteria and acidic conditions resulting from bacterial activitity of various types.

 

[tmz]

Originally Posted by tmz
"cooking", purging, or curing LR utilize this process.

Mineralization or breakdown to refractory organics /aka sinking phosphate seem more likely, imo.
"Cooking" usually means leaving the rock in a darkened bin of water for a year or so .I think it may work as a result of bacterial degradation and mineralization ,sinking the phosphate and other elements in refractory organics or via mineralization. If it is a process that simply liberates the phosphate as you suggest via unidentified solubilizing bacteria with no export then where do you suppose the phosphate goes in the end?
it becomes the detritus you see at the bottom of the tank in which you are "cooking" the LR in. what else do you think that detritus is comprised of?

Sediment from mineralization and perhaps some refractory organics that sink the phosphate.

Why would there be a detritus degradation after a year? If there was why wouldn't the Pi just go back into the rock? In your unconnected dot the phosphate would just keep circulating back into the rock as some special unidentified solubilizing bacteria would break down the sediment and the refractory organics.That just doesn't happen to a measureable extent .If it did what would be the point of "cooking"?

 

[Reefin' Dude]

i am talking about the acidification from the decomposition of the waste organic material, not from the solubilizing bacteria.

the point of the solubilizing bacteria is that there are more than one way to remove P from calcium carbonate.

the point is that we have been told that the low pH in a substrate is able to help in the movement of P, but we seem to miss what is causing the decrease in pH, and why the pH is lower as one goes into the substrate. we blame it on the benthic organisms, when the bacterial population in a substrate working on the waste organic material is greater producer of CO2. the more waste material, the more bacteria, the lower the pH.

G~