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

[rounder45]

We run skimmers, change water, run GFO and GAC, dose carbon, and harvest algae, all in an effort to remove excess nutrients. Why do all these things if absorbing excess nutrients within the system is a good thing?

I don't understand...
What nutrients are being absorbed? They are being recycled into living organisms thus the fauna required for proper sand bed function. If the nutrients are recycled and supportive to life, the reliance on our need to remove all excess nutrients must reduce. Now, I see this as good. Seems the more a system relies on external sources for function and equilibrium, the more it is also subject to problems if those external resources are diminished or inconsistent.

 

[Nano sapiens]

I don't understand...
What nutrients are being absorbed? They are being recycled into living organisms thus the fauna required for proper sand bed function. If the nutrients are recycled and supportive to life, the reliance on our need to remove all excess nutrients must reduce. Now, I see this as good. Seems the more a system relies on external sources for function and equilibrium, the more it is also subject to problems if those external resources are diminished or inconsistent.

The assimilation of nutrients by an organism isn't anywhere near 100%, but more like maybe 10-30% (depends on the organism and environment). Much of the initial waste product can then be assimilated by various organisms, but not all of it, so there is a buildup in a closed tank system of various substances (phosphates, polyphenols, etc.).

GFO, GAC, water changes, skimming, detritus removal, etc. are used to deal with these excesses.

 

[tmz]

I'd love to see more (and rigorously controlled) experiments. Closed flow chambers preceded by strong UV sterilization, some GAC, and very fine mechanical filtration would be a good start. I'd be curious to see near zero PO4 vs .1 vs .5 vs 1 with algae and alelopathy removed from the equation, especially if P could be balanced against N.

I'm more in the low/ middle group on the question of phosphate levels. Anecdotally ,
If I let PO4 go much higher than 0.06 /.07ppm my corals don't seem to do as well and algae becomes an issue.;sometimes cyano too.
I don't think a lack of density in skeletal mass is a natural state or helpful. To me it indicates the coral is having some difficulty directing calcification and carbonate crystal growth is likely slowed by PO4 bound to calcium in lieu of carbonate. Don't know if driving more ATP and possibly accelerating the calcification process is a good thing either although I think it may help the coral cope with the increase in PO4 binding to forming skeletal mass. That's just me.
Further,I don't think you can take algae or it's by products out of the equation unless some other nutrient like iron perhaps is limited which may be a less than desireable condition for many organisms. I know there are oligotrophic algae but they are less problematic at least in my case.I don't think you think you can filter out algae without filtering out planktonic food sources? Not sure I'd wan't to filter out all the phytoplankton anyway.
PO4 at 0.03 or less limits much of the green algae and cyanobacteria ,ime.
Nutrient balance C:N is achievable . I know there are different thoughts on this. question . I've always been skeptical of any value to zero PO4 and NO3 but I'm also skeptical that high levels are at all helpful.

Anecdotally I've had a solid 5 plus year run with sps and other corals by keeping PO4 and nitrogen available in low amounts but not zero.

 

[elegance coral]

None of this is based on opinion; it's based on 20 years' experience involving hundreds of personal and commercial tanks, plus - more importantly - known science about sediment/benthic ecology from the primary literature and my own research. I would be happy to provide the dozens of papers specifically on this topic that have led me to my conclusions; they may be behind a paywall but usually the abstracts are open access.

Sometimes it's amusing when you realize there are people telling professional marine biologists that our understanding of such things are flat out wrong

Sometimes it's amusing when people feel the need to resort to such tactics in the middle of a debate.

A wise man once told me, "If you feel the need to deviate from the subject of a debate, to make personal statements about your own accomplishments, then you've probably already lost the debate. If your argument is strong enough to stand on its own, you'll have no need for such meaningless, self promoting, statements."

"Professional marine biologists" in this hobby have a tendency to describe in great detail all the intricate workings between tiny organisms within the sediments of our systems, and in nature, but they either don't understand, or simply choose to ignore the reality of the big picture.

"Professional marine biologists" don't like to admit that it is directly due to the activities of these tiny organisms that the mangrove trees are able to grow in mangrove swamps. These tiny organisms produce the fertilizer (like N and P ) that fuel the growth of these massive mangrove forests.

"Professional marine biologists" will talk about the tiny creatures in the sediments of the great abyssal plane while ignoring the fact that it is these organisms that fuel the largest algae blooms this planet has to offer.

"Professional marine biologists" will tell hobbyists about the insignificant and meaningless ability of tiny creatures to feed and produce offspring, but they don't seem to have the ability to inform hobbyists that it is the activity of these tiny creatures that's fueling their algae problems.

It amazes me that "professional marine biologists" have succeeded in causing hobbyists to ignore the world around them, and blindly fallow the illusion of the world that "professional marine biologists" have portrayed to them. Maybe it's due to the fact that marine life can seem so alien to us? People are so willing to believe marine life lives by a completely different set of rules than the rest of us.

People keep all kinds of animals in small enclosures. Regardless of species, everyone understands the importance of keeping the bottom of the animals enclosure clean. Even the small child that wins a goldfish at the fair quickly learns this. "Professional marine biologists" have convinced hobbyists that the animals we keep are somehow different. That our pets enjoy living in a small enclosure with six inches of their own filth on the bottom. If we saw a multitude of tiny worms and bugs on the bottom of any pets enclosure we would see this as a really bad thing, and probably panic before cleaning the enclosure. "Professional marine biologists" lead people to believe that the more poo eating bugs you have on the bottom of the tank the better, despite the fact that it goes against everything else they know and understand about nature and keeping animals in small enclosures.

So....... Will I say that a "professional marine biologists understanding of such things is flat out wrong"? Absolutely. I don't care what paper is hanging on the wall behind someone's desk. What they say is either true and factual, or it isn't.

 

[Brummie]

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

Sometimes it's amusing when people feel the need to resort to such tactics in the middle of a debate.



A wise man once told me, "If you feel the need to deviate from the subject of a debate, to make personal statements about your own accomplishments, then you've probably already lost the debate. If your argument is strong enough to stand on its own, you'll have no need for such meaningless, self promoting, statements."



"Professional marine biologists" in this hobby have a tendency to describe in great detail all the intricate workings between tiny organisms within the sediments of our systems, and in nature, but they either don't understand, or simply choose to ignore the reality of the big picture.



"Professional marine biologists" don't like to admit that it is directly due to the activities of these tiny organisms that the mangrove trees are able to grow in mangrove swamps. These tiny organisms produce the fertilizer (like N and P ) that fuel the growth of these massive mangrove forests.



"Professional marine biologists" will talk about the tiny creatures in the sediments of the great abyssal plane while ignoring the fact that it is these organisms that fuel the largest algae blooms this planet has to offer.



"Professional marine biologists" will tell hobbyists about the insignificant and meaningless ability of tiny creatures to feed and produce offspring, but they don't seem to have the ability to inform hobbyists that it is the activity of these tiny creatures that's fueling their algae problems.



It amazes me that "professional marine biologists" have succeeded in causing hobbyists to ignore the world around them, and blindly fallow the illusion of the world that "professional marine biologists" have portrayed to them. Maybe it's due to the fact that marine life can seem so alien to us? People are so willing to believe marine life lives by a completely different set of rules than the rest of us.



People keep all kinds of animals in small enclosures. Regardless of species, everyone understands the importance of keeping the bottom of the animals enclosure clean. Even the small child that wins a goldfish at the fair quickly learns this. "Professional marine biologists" have convinced hobbyists that the animals we keep are somehow different. That our pets enjoy living in a small enclosure with six inches of their own filth on the bottom. If we saw a multitude of tiny worms and bugs on the bottom of any pets enclosure we would see this as a really bad thing, and probably panic before cleaning the enclosure. "Professional marine biologists" lead people to believe that the more poo eating bugs you have on the bottom of the tank the better, despite the fact that it goes against everything else they know and understand about nature and keeping animals in small enclosures.



So....... Will I say that a "professional marine biologists understanding of such things is flat out wrong"? Absolutely. I don't care what paper is hanging on the wall behind someone's desk. What they say is either true and factual, or it isn't.

Hi EC. Just for clarification, would you say dung Beatles or earthworms are dangerous. If so, we could all be in big trouble, up to our necks in it in fact. And if so, how does this differ from a well looked after aquarium? Cheers
BTW, im not a follower of aquarium fashions, just after a bit of logic to this topic

 

[Amphiprionocellaris]

Sometimes it's amusing when people feel the need to resort to such tactics in the middle of a debate.

A wise man once told me, "If you feel the need to deviate from the subject of a debate, to make personal statements about your own accomplishments, then you've probably already lost the debate. If your argument is strong enough to stand on its own, you'll have no need for such meaningless, self promoting, statements."

"Professional marine biologists" in this hobby have a tendency to describe in great detail all the intricate workings between tiny organisms within the sediments of our systems, and in nature, but they either don't understand, or simply choose to ignore the reality of the big picture.

"Professional marine biologists" don't like to admit that it is directly due to the activities of these tiny organisms that the mangrove trees are able to grow in mangrove swamps. These tiny organisms produce the fertilizer (like N and P ) that fuel the growth of these massive mangrove forests.

"Professional marine biologists" will talk about the tiny creatures in the sediments of the great abyssal plane while ignoring the fact that it is these organisms that fuel the largest algae blooms this planet has to offer.

"Professional marine biologists" will tell hobbyists about the insignificant and meaningless ability of tiny creatures to feed and produce offspring, but they don't seem to have the ability to inform hobbyists that it is the activity of these tiny creatures that's fueling their algae problems.

It amazes me that "professional marine biologists" have succeeded in causing hobbyists to ignore the world around them, and blindly fallow the illusion of the world that "professional marine biologists" have portrayed to them. Maybe it's due to the fact that marine life can seem so alien to us? People are so willing to believe marine life lives by a completely different set of rules than the rest of us.

People keep all kinds of animals in small enclosures. Regardless of species, everyone understands the importance of keeping the bottom of the animals enclosure clean. Even the small child that wins a goldfish at the fair quickly learns this. "Professional marine biologists" have convinced hobbyists that the animals we keep are somehow different. That our pets enjoy living in a small enclosure with six inches of their own filth on the bottom. If we saw a multitude of tiny worms and bugs on the bottom of any pets enclosure we would see this as a really bad thing, and probably panic before cleaning the enclosure. "Professional marine biologists" lead people to believe that the more poo eating bugs you have on the bottom of the tank the better, despite the fact that it goes against everything else they know and understand about nature and keeping animals in small enclosures.

So....... Will I say that a "professional marine biologists understanding of such things is flat out wrong"? Absolutely. I don't care what paper is hanging on the wall behind someone's desk. What they say is either true and factual, or it isn't.

Just to clarify, lest someone think I am claiming to be something I am not, I am not strictly a marine biologist; my PhD is in marine sciences - a combination of physical, chemical, and biological oceanography - and my specific field of research and expertise is benthic ecology, especially the impacts of benthic fauna on nutrient flow through a system. Considering and assembling the big picture of the whole system is at the core of what I do, which is why I will stand by my understanding of an aquarium system as I've described until I am shown with empirical evidence that it is wrong. That's certainly possible, considering how very little we actually do know of the systems ecology of both natural and captive sediments/systems, but I will also say that the application of my understanding into my own aquaria has given excellent and consistent results, for what little that observation is worth.

 

[rounder45]

The assimilation of nutrients by an organism isn't anywhere near 100%, but more like maybe 10-30% (depends on the organism and environment). Much of the initial waste product can then be assimilated by various organisms, but not all of it, so there is a buildup in a closed tank system of various substances (phosphates, polyphenols, etc.).

GFO, GAC, water changes, skimming, detritus removal, etc. are used to deal with these excesses.

that's 10-30% more assimilation than if the organisms were not there... the waste is there in every tank regardless of the presence of infauna. Nobody saying anywhere that a DSB will eliminate the need for quality additional filtration.

 

[rounder45]

People keep all kinds of animals in small enclosures. Regardless of species, everyone understands the importance of keeping the bottom of the animals enclosure clean. Even the small child that wins a goldfish at the fair quickly learns this. "Professional marine biologists" have convinced hobbyists that the animals we keep are somehow different. That our pets enjoy living in a small enclosure with six inches of their own filth on the bottom. If we saw a multitude of tiny worms and bugs on the bottom of any pets enclosure we would see this as a really bad thing, and probably panic before cleaning the enclosure. "Professional marine biologists" lead people to believe that the more poo eating bugs you have on the bottom of the tank the better, despite the fact that it goes against everything else they know and understand about nature and keeping animals in small enclosures.

don't the "poo eating bugs" stabilize their populations based upon nutrients available? What professional is saying overpopulation is better?
Skimming... ok... the primary removal tool of organics is a skimmer...so, why is it better to skim the thinnest top layer of the tanks water as opposed to the bottom of the tank?

 

[rounder45]

I have a question... with the importance of fauna in a DSB, should this also be stressed in a shallow sand bed as well?

 

[Brummie]

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

don't the "poo eating bugs" stabilize their populations based upon nutrients available? What professional is saying overpopulation is better?

Skimming... ok... the primary removal tool of organics is a skimmer...so, why is it better to skim the thinnest top layer of the tanks water as opposed to the bottom of the tank?

Don't think you can overpopulate in the long term. Short term over populations would surely end in a crash. Folks skim the surface because that surface has already gained substances readily skimmable.

Personally, without soil, our world would be an inhabitable space. It's ok to take a panda and put it in a box, clean it out religiously, but it will not thrive. It needs an appropriate ecosystem.

 

[Fredfish]

that's 10-30% more assimilation than if the organisms were not there... the waste is there in every tank regardless of the presence of infauna. Nobody saying anywhere that a DSB will eliminate the need for quality additional filtration.

That 10 to 30% is per pass through the digestive tract of a given organism. All this detritus gets consumed many times over. Each organism is inefficient in digesting organics, but as a system, the entire sandbed ecosystem is very efficient in its digestion and conversion to living organic matter.

 

[tmz]

A few thoughts:

Terrestrial animals we keep in cages or pens do not rely on degrading material for nutrients via adsorbtion or as food via bacteria and other indigenous sources as cnidaria,scletarians and other marine animals do. Housepets don't worry about a supporting symbionts to manufacture sugars either. The comparisons between these animals and terrestrial house pets are not apt,imo.
If all the degrading material infuana and epifuana were swept out what would they use for nitrogen and phosphorous or consume as food?

I do siphon some detritus in my tank as it can be harmful in excess but some is manageable and useful ,ime; just as some SRP and fixed nitrogen are .

The optimal balances in a tank will be most heavily influenced by feeding vs. an export system';skimming, macro algae harvesting , gac, organic carbon dosing ,gfo or other adsorbents and so on and not by a maintained substrate however deep it may be either in terms of excess nutrients or paucity,imo.

A skimmer removes organics that are trapped at the air water interface between the bubbles and the and the water they are in . It is an effective means of organic export particularly for amipathic organics ; GAC is as well,primarily for hydorphobic organics and most notably for discoloring compunds.

Some infauna and epifauna live in shallow sand or live rock just fine,IME. I have many of spaghetti worms and other polychates in my tanks evident in shallow sand . Lots of other organisms as well.

 

[elegance coral]

Hi EC. Just for clarification, would you say dung Beatles or earthworms are dangerous. If so, we could all be in big trouble, up to our necks in it in fact. And if so, how does this differ from a well looked after aquarium? Cheers
BTW, im not a follower of aquarium fashions, just after a bit of logic to this topic

Dung Beetles and earthworms in and of themselves are not dangerous. However, if you put a rabbit in a cage, and allowed its waste to build up on the bottom, to the point that it supported large numbers of dung beetles and earthworms, the conditions within the cage would become dangerous for the rabbit. In order to keep the rabbit healthy, in a small enclosure, you would have to keep the accumulation of rabbit poo and left over food at such low levels it could never support large numbers of dung beetles and earthworms.

 

[GroktheCube]

That's a false equivalence.

The care of a mammal in a cage is completely incomparable to that of aquatic life. We don't "cycle" mammal cages so that bacteria can detoxify liquid nitrogenous waste, we don't keep mammals that use pee and poo as an important part of their diet (like corals do), we don't keep mammals that are accustomed to huge quantities of food floating around in the air, and we don't rely on bacteria to do the lion's share of waste detoxification in a mammal's cage.

Allowing the waste of a mammal to collect on the floor it is walking on encourages the growth of bacteria harmful to it, generates dangerous levels of ammonia, dirties its skin and fur preventing natural cleaning and homeostatic mechanisms from functioning, and almost inevitably leads to severe bacterial infections of the skin resulting in death.

When looking at these facts, how does one jump from "We need to clean up the pee and poo of caged rabbits regularly or they will die." to "DSBs are bad."?

That's like saying "My corals respond well to Oysterfeast, therefore I should feed my rabbit raw seafood." or "My rabbit is happier when it gets some time to run outside of its cage, therefore I should throw my fish on the floor."

Other than the fact that both animals are being kept in captivity and require some level of keeper intervention to survive, they have virtually nothing in common.

 

[elegance coral]

that's 10-30% more assimilation than if the organisms were not there...

The assimilation is roughly zero. The only way to achieve any assimilation at all would be to have a population that is growing. It doesn't matter that some individuals are assimilating nutrients if there is an offsetting number of individuals dyeing and releasing their nutrients back into the environment.

the waste is there in every tank regardless of the presence of infauna.

Infauna can not survive without food. The amount of waste and the number of infauna are intimately linked. Generally speaking, if you remove waste you reduce the number of infauna. Increase the amount of waste and the number of infauna increases.

 

[elegance coral]

don't the "poo eating bugs" stabilize their populations based upon nutrients available?

Yes. Absolutely.

What professional is saying overpopulation is better?

I don't know that anyone is using the term "overpopulation", but many "professionals" do believe that massive numbers of infauna is a good thing. Like Ron Shemik with his hundreds of thousands of individuals in his 40 gallon tank.

 

[hereticlosmorte]

i think the real question is, are there any critters turning over the DSB or not? if one were to have snails or other sifting/burrowing critters, it's much less likely for said sandbed to become toxic.

without them i could see it becoming problematic.

 

[kaskiles]

I have to admit, the aspects of this thread dealing with sand beds and fate and transport of phosphorus are much more interesting than some peoples exploits with the principles of reasoning...

 

[rounder45]

The assimilation is roughly zero. The only way to achieve any assimilation at all would be to have a population that is growing. It doesn't matter that some individuals are assimilating nutrients if there is an offsetting number of individuals dyeing and releasing their nutrients back into the environment.



Infauna can not survive without food. The amount of waste and the number of infauna are intimately linked. Generally speaking, if you remove waste you reduce the number of infauna. Increase the amount of waste and the number of infauna increases.

so how would waste be removed while your on vacation in Hawaii?... or if laid up at the hospital after surgery? Or, whatever... I'm guessing your suggesting a system reliant on regular frequent removal of waste manually is the safer bet... so back to what happens when a tank so reliant on your active participation does not or cannot receive it?

 

[elegance coral]

Okay....... Lets approach this from a slightly different angle.

Coral reefs around the world are suffering from rising nutrient levels. If we were to put a time laps camera on one of these reefs, what would we see?

If we started on a clean, low nutrient, healthy, growing, coral reef, we would see virtually every available surface covered with a thin layer of growing stony coral tissue. It's highly likely that we would see an abundance of fish as well. As nutrient levels rise, we would begin to see void spots appearing on the reef. Areas of bare limestone/coral skeletons. Soon, we would see other organisms appearing in these void spots. Organisms like sponges, soft corals, gargonians, and sea fans. In time, we would see fewer and fewer stony corals as these other organisms take their place. We would probably still notice quite a few fish in the area, but there's likely to be a noticeable decline in populations. As nutrients continue to rise, we may see macroalgae, like Caulerpa, appearing in spots on the reef. As time passes, and nutrient levels continue to rise, this algae may begin to dominate the reef. Overgrowing organisms like sponges and soft corals. By this time there will be very few, if any, stony corals left. As this is taking place, we may notice filamentous algae (hair algae) appearing in patches. As nutrients continue to rise, we see the soft corals going the way of the stony corals, and filamentous algae taking the place of macroalgae. In the end, were left with a carpet of hair algae, murky water, and the rare passing of a fish.

Naturally, these stages would overlap, and the exact species involved may vary greatly, but the above is a general representation of what happens on a coral reef as nutrient levels climb.

So..... If we start a reef tank with clean rock, clean sand, and clean water, we create an environment that closely resembles the reef at the beginning of the scenario above. Where it goes from there is in our hands. If we keep the system relatively clean, and low in nutrients, we can support a reef that closely mimics the reef at the beginning of the scenario above. The higher we allow the overall nutrient level to become, the more rotting organic matter we allow to accumulate, the more tiny poo eating infauna we support, the closer we push the system to the conditions of the reef at the end of the scenario above.