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

[tmz]

Maybe channeling and transport by infauna along with some useful level of advective flow could provide enough nutrients to sustain some significant N2 producing anaerobic activity in some deep sand areas supplementing those already occurring closer to the surface .

Keeping the sand and interstices clean and sustaining the infauna has not proven to be an easy goal to reach for many in the long run .

It seems to me it might be easier to get consistent results in nitrogen reduction , keeping a shallower bed with a bigger footprint and brisk flow or perhaps even a bed of gravel with large interstices along with upward flow built in.
Using an RUGF with organic carbon dosing would be an interesting arrangement with upward flow providing a stream of nutrient and oxygen laden water to the faculatative heterotrops colonizing the substrate . This arrangement might also enhance some types of infuana and epifuana . Of course the bacteria could clog it up and organic matter might still settle in but with large media and interstices it would be a less likely and easier to siphon if necessary witthout drawing up the larger substrate.

 

[Fredfish]

...

Keeping the sand and interstices clean and sustaining the infauna has not proven to be an easy goal to reach for many in the long run .

Agreed. Dr. Schimek seemed to think scale was the issue. It was simply impossible to maintain diverse population long term. Hence the recommendation for periodic recharges from other aquarists. Sandbeds on reefs have the advantage of a constant import of larvae from other parts of the reef. A larger shallower bed would probably be a step in the right direction.

 

[billsreef]

Having at one point been culturing and selling sand bed fauna, I think the problem people seem to have is from not disturbing those sand beds on occasion. Never had a problem keeping a constant supply of sand bed fauna going, and I was constantly disturbing the beds to pluck out fauna and removing sand to sell as LS...that was rather full of fauna. Those disturbances, while might drop the population in a localized area of the bed, also saw quick repopulation. Even my old DSB display tank, I never had fauna issues, though I did periodically (every few months or so) siphon a small area of the sand bed with a slow flow vacuum.

 

[saf1]

The fact that someone has maintained a DSB and managed not to kill every single creature they added, is not evidence that the DSB is performing some beneficial task.

This holds true for anything in this hobby. I can't stress this enough that there is no standard or formula for success in this hobby. If there was we would all be running similar systems and that just isn't the case.

Furthermore, the same argument you made about someone maintaining a DSB with longevity is no different than someone running a tank with or without a skimmer, weekly water changes, or any number of other snake oils corporate America is pushing down the hobbyist throat.

 

[tmz]

Not clear as to your meaning. Do you think sand beds, skimmers and water changes are:
"sna ke oils corpoirate Amercia is pushing down the hobbyist throat"?

I agree there is no standard way to enjoy the hobby .

 

[Amphiprionocellaris]

It seems to me it might be easier to get consistent results in nitrogen reduction , keeping a shallower bed with a bigger footprint and brisk flow or perhaps even a bed of gravel with large interstices along with upward flow built in.
Using an RUGF with organic carbon dosing would be an interesting arrangement with upward flow providing a stream of nutrient and oxygen laden water to the faculatative heterotrops colonizing the substrate . This arrangement might also enhance some types of infuana and epifuana . Of course the bacteria could clog it up and organic matter might still settle in but with large media and interstices it would be a less likely and easier to siphon if necessary witthout drawing up the larger substrate.

I think this might be of interest to you http://www.sciencedirect.com/science/article/pii/S0016703712004759. Unfortunately, that may be behind a paywall, but if you'd like the whole article, I'd be glad to send the pdf (it's less than 700 kb); just shoot a PM.

I think you're spot on for what is potentially a really awesome new direction for NNR in the hobby (pardon me if I'm [unabashedly and un-apologetically] completely biased...it's what I love). Advection DOMINATES on the reef, so why don't we try to use that ourselves? I predict that we could essentially eliminate problematic nitrate from our systems using a flow-through carbonate filter. Of course, let me say, I'm not saying traditional DSB systems don't work (look at my posts; anyone will see I'm asand bed crusader), but I think there are some really awesome new discoveries that we can really use to take the hobby to the next level.

 

[Brummie]

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

I think this might be of interest to you http://www.sciencedirect.com/science/article/pii/S0016703712004759. Unfortunately, that may be behind a paywall, but if you'd like the whole article, I'd be glad to send the pdf (it's less than 700 kb); just shoot a PM.

I think you're spot on for what is potentially a really awesome new direction for NNR in the hobby (pardon me if I'm [unabashedly and un-apologetically] completely biased...it's what I love). Advection DOMINATES on the reef, so why don't we try to use that ourselves? I predict that we could essentially eliminate problematic nitrate from our systems using a flow-through carbonate filter. Of course, let me say, I'm not saying traditional DSB systems don't work (look at my posts; anyone will see I'm asand bed crusader), but I think there are some really awesome new discoveries that we can really use to take the hobby to the next level.

So your saying a carbon source (ie an algae bed) combined with a flow through carbonate substrate may indeed be beneficial?

 

[Amphiprionocellaris]

So your saying a carbon source (ie an algae bed) combined with a flow through carbonate substrate may indeed be beneficial?

Absolutely. Although the carbon source is up for debate, that is precisely what I would advocate in terms of nitrate removal. That said, there is of course a lot of wiggle room in terms of the carbon source etc., etc.. and personally, I hesitate to make blanket statements just by virtue of the sheer amount of variability out there in terms of husbandry...I use the same method in my aquarium with great success, but I know that I am only one sample point of many.

 

[Brummie]

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

Absolutely. Although the carbon source is up for debate, that is precisely what I would advocate in terms of nitrate removal. That said, there is of course a lot of wiggle room in terms of the carbon source etc., etc.. and personally, I hesitate to make blanket statements just by virtue of the sheer amount of variability out there in terms of husbandry...I use the same method in my aquarium with great success, but I know that I am only one sample point of many.

Cheers. It seems most algal derived exudates are consumed within the water column. This may be a missed opportunity

 

[tmz]

I think a good proportion of algae exudates tend toward a refractory nature at least more so than coral slime for example from what I've read about them; some are allelopathic. As such algae exudates might contribute more to clogging the sand than to heterotrophic bacterial activity.

Anecdotally , I always have a mess at the substrate surface when when I put algae over sand in a refugium .

Personally, I'm thinking soluble organics close to acetate( ie ethanol or acetic acid ) might be an easy way to bump the organics if needed for an extra boost in dentirification in a bed or tower of of aragonite sand or coarser material subject to moderate flow. If we keep goingdown this path I'm sure someone is going to suggest zeolites.

This is one early study on algal exudates.I read a while ago:

http://www.nova.edu/ncri/11icrs/proceedings/files/m25-10.pdf

The discussion on the last page points up some of the concerns about algae exudates in coral sands.

 

[tmz]

I predict that we could essentially eliminate problematic nitrate from our systems using a flow-through carbonate filter

That's what I'd like to see. Sand beds would still have value for critters and aesthetics a more easily manageable role,imo

Thanks for the comments and the link to the study. I'll be in touch.

 

[billsreef]

With the amount of water flow most of us maintain in our tanks, I expect there is a fair amount of advection causing water movement through our sand beds

 

[tmz]

Under the rock structures advection is more of a force . Sand granules contribute too but not to much depth which is why remote sand in a bucket notions don't pan out as well as sand with rock or other obstructions to current on it usually in the aqaurium ,at least not for me.
There is a useful analyses of advection and diffusion including several cited studies and measures of the flow into the substrate in Sprung and Delbeek's 'the Reef Aqauirum Vol 3. The speed of the current and the size of the obstruction govern the water pressure changes and the pressure drop.
I think it still requires more of a force than we can generate in a tank to move enough nutrients down deep in a bed for significant ongoing NO3 reduction in the deep areas . A clean unclogged bed with infauna adds to the process as discussed.

As an aside ,I first learned about advection when I was the Personnel Director for Region 8 of the NY state Dep't of Transportation many many years ago. We were hiring engineers and technicians . Part of the interview process involved the candidate's knowlege of it since they were to be assigned to oversee the design and construction of a span over the Hudson River between Beacon and Newburg;so I picked up some bare bones knowlefge from our engineers along the way. There was quite a buzz about a new pontoon design, IIRC. Never thought it would be useful in a hobby later in life.

 

[Randy Holmes-Farley]

but it does have the ability to effect the corals that we try to grow on these same sediments.

How does it impact the corals and not get into the water column?

 

[billsreef]

Just based on my own tanks over the years, never had more than 5ppm NO3 at anytime, and usually less. So IMO with good reef type circulation, and the rock work arranged to keep the majority of the sand bed open, enough throughput occurs via advection and biological process for decent NO3 reduction. Before I had to breakdown my tanks to move to Miami, my display tank had been up and running with a DSB refugium for 15 years....never crashed or turned into a eutrophic algae filled mess either

 

[Reefin' Dude]

I can go ahead and say that - unless there is something fundamentally different going on in the home aquarium - this material takes decades to accumulate in most cases to the point of affecting permeability. It is much faster in small tanks, of course, because the volume of sediment is smaller, so a semi-fixed rate of refractory material accumulation leads to a larger percent change.

there is something fundamentally different in the home aquarium than in nature, that is what i have been trying to say. in nature the substrates are disturbed on a regular basis. sometimes every tide. our puny little 4" substrates are nothing compared to the amount of movement of a substrate in on those reefs that have them. when tropical storms come through, the substrates can be disturbed several feed down. this is a fundamental difference between what is going on in nature and what we are told to do in our home systems. WHY? this is probably the biggest point i have been trying to make. substrates in nature are "siphoned" clean regularly. the built up waste organic material is washed away and the benthos is allowed to rebuild in relatively waste free environment.

Some people (even DSB supporters) debate this next one, but I do like to occasionally disturb the sand bed in small sections. Occasionally (every few months or so) I do like to vacuum small sections of the sand bed, no more than 25% if that much at one time. Yes, you will loose a certain amount of fauna in that small patch, however, I find that patch quickly repopulates from the surrounding undisturbed sand bed. Sometimes I've even simply stuck a turkey baster into the sand and "fluffed" it up a bit to just shake it up a bit. More or less, the idea is that such sediments get occasional major disturbances from storms, so I simulate that storm in my tanks So far I've never seen more detritus shake out of the sand bed than I'd find by stirring up the sand bed at the bottom of a coral head on the reef

and how is this not what i have been saying the entire time? we must clean up after our pets on a regular basis. get the build up of waste organic material out of the substrate so that the benthos have more room again. just flushing the toilet or taking out the trash.

Shh, your going put a monkey wrench in the arguments of the anti DSB crowd. They like to forget they have all the same nutrient issues, and that bare bottom tanks crash just as often as any other method

have i not been saying this the entire time? it is all about taking out the trash and flushing the toilet. it doesn't matter what is on your bottom.

If the overall content (including what's in the biomass and sediment) was such a problem, reefs wouldn't exist as we know them.

which reefs? some reefs have very little substrate in and around them (outer reefs). other do (lagoons). those that do not have a lot of substrate are the ones suffering the most from eutrophication from terrestrial sources.

I agree that if you have algae on the sand it is an issue. Otherwise, I don't see it as any concern. Who cares about the "overall content"? If it isn't impacting creatures in the water column, it seems a minor point to me.

i thought the algae was showing that there is actually iP leaving the substrate through dissolution.

think of the "overall content" as potential P. the greater the total P the greater the chance of all of that P being released back into the water column at a rate faster than the system can handle. either from die off, disturbing of the substrate without siphoning the material, rock slides, powerhead getting dislodged or falling into the substrate, the list can be infinite. it is just keeping the total amount of P as low as possible to maintain the must have organisms.

G~

 

[Reefin' Dude]

OK lets take it in order. . .

You take my words too literally. Science shows us that real world reef sediments are NOT filled with waste. What scientific papers have shown the rate of accumulation of waste products in home reef aquarium sediments? Answer: not a one. Yes waste sinks, but we as aquarists are using a myriad of methods to export waste and one part of that is the microbial breakdown of nitrogenous and phosphorous organics which then become amenable to removal by one or more methods.

How this process works in a home aquarium has not been studied and until it is you can not say unequivocally that waste is "sinking" AND remaining in a DSB.

If it did then DSBs would ruin all tanks and that is simply not happening; so in this first case you are clearly wrong.

look at any oceanic phosphate cycle. there is an arrow sinking P into the substrate. where it is sunk until geological changes. if this didn't occur, then how do we have land based organisms? how does the P get back up to the land organisms, if it is completely recycled in the marine environment?

all that is being said here is that P gets sunk into substrates. it just needs to be cleaned on a regular basis in order to maintain the desired dissolved inorganic nutrient level to support the desired organisms.

just take any substrate older than a few months and stir it up. what do you see? was that material there before? no, where did it come from? how is this not a visible and concussive data showing that waste organic material is building up in a substrate?

But,

before I go further with dissecting your reply from long ago let me ask your opinion on the central tenet of this thread.

Do you believe that DSBs are ticking time bombs and should never be used in a home reef type aquarium?

nobody is saying that it should not be used in the home aquarium. we are just saying that the way we are told to maintain them is sinking nutrients. it is not magically making them disappear. nutrients go into the substrate. recycling nutrients in a substrate is not exporting. we are just suggesting getting a better understanding of how substrates work. how they work in nature. we in the hobby industry are not treating substrates the same way they are treated in nature. massive regular disruptions on a regular basis.

There is a difference between having lots of organic content available to sand bed organizms, which is quickly consumed, and having a large accumulation of unconsumed organic material (non refractory) in the sand bed.

not here isn't. it is still an increase in total nutrients of the system. what keeps the "unconsumed organic material" from becoming consumable again? why would we want this large accumulation even in the substrate? what good is it doing? wouldn't it get in the way of the normal biological processes going on?

i guess i am confused, is it useable for the organisms in the substrate, or is it unimportant? make up your mind.

Lots of people feed an abundance of food to their fishes and corals. Nobody considers that a ticking time bomb. In fact, many consider these feeding levels essential to the health of the tank. Everybody finds a way to manage the resultant organics. Having a thriving sand bed is just another tool to manage nutrients. Nothing more, nothing less.

i do. how can it not be? it is more nutrients going into the system. unless there is an equal amount of organic material being removed, the system is increasing in total nutrients. how is this a good thing? a substrate is just hiding the increase in total P. with all of those organisms and all of that "unconsumed organic material (non refractory)". it is still there, and it was not there when you setup the system.

Out of curiosity, what percentage of the total mass of living organisms in an aquarium does 50,000 sand bed critters represent? is it 2%, 10%, 50%? If we are going to fear these creatures, should we not quantify the threat?

so now it is a threat? make up your mind. it doesn't matter what the percentage is. they are still there and if they are not supporting the desired environment wishing to be emulated by the aquarist, then they are harmful. they represent an increase in total nutrients of the system.

I love phylosophical discussions. If you ask the same question regarding the portion of your tank above the sand bed, what answer do you get? Do you get to a single anwer that everybody, or even a significant number of hobbyists can agree on? Should we compare it to healthy organisms and systems in the wild?

this is less philosophical than you think. as you move further down a food chain the total amount of organisms has to increase in order to support the ones above it. the more levels one has, the more total nutrients there must be in the system just from the sheer biomass of support organism. all we are saying is why is all of this necessary? just feed and remove the waste of the must have organisms.

If we apply this same logic to any other piece of equipment or system used in/on our tanks, what do we come up with other than: "it works for me, but I have no idea if it is beneficial or not."

For instance, what proof is there that skimmers are performing some beneficial task. Sure, lots of people use them and manage not to kill every single creature added, but where is the proof that skimmers are beneficial?

the skimmate is pretty good indicator that there is a lot of organic material being removed from the system. siphoning up detritus will also give a good visual indicator that waste organic material is being removed.

I would submit that if you can maintain a tank with similar "health" to a non deep sandbed system, that sandbeds are as 'beneficial' as systems with other nutrient control systems like skimmers, and various chemical media.

nobody is saying that there are not many different ways to remove nutrients from a system. what is being horse beaten here is that some people still believe that detritus is not accumulating in a substrate and that is should not be removed on a regular basis. regular basis being at a rate that provides the desired soluble inorganic nutrients to the must have organisms.

Can you quote one of these assumptions not born out by reality, or is this just a baseless personal jab with absolutely no foundation to support it?

This is not a personal jab;just a clarification of what appears to be an overstatement of opinion as fact from post 509.The context was in a response to Bill's statement regarding" bacteria on up"

They are irrelevant to the total P content of our glass boxes, but they are a major contributor to the "P that can cause issues in our tanks". They take organically bound P, which is harmless, and convert it into inorganic P, which causes issues in our tanks. They do the same with other elements that could potentially cause issues in our tanks, like heavy metals. The more of these types of critters we have, the more inorganic P they're producing.

Maybe some organisms do at some stages of excretion but they also produce exudates ,larvae etc,that are organic; they may also take up inorganic P .
I'm skeptical you can support that statement as it is. Bacteria assimilate inorganic P as far as I know converting it to organic P for example They take up some metals too. Some other organisms do as well.Sponges are another known prime example of organisms that take up inorganic P and release organic P.

and where is this mass migration of larvae and exudes from the substrate? stir up any substrate and i can show you the larvae and exudes still there, but i am not seeing any leaving the substrate? this is a pretty easy observation here.

I would expect that how active or inactive an area in the sand bed is depends entirely on how well populated that bed is.

how is this not showing that there is an increase in total P. in order to have any population of an organism, it must have resources. a substrate that is fully populated must have enough resources to support all of that population along with all of the support organisms and resources.

Agreed. Dr. Schimek seemed to think scale was the issue. It was simply impossible to maintain diverse population long term. Hence the recommendation for periodic recharges from other aquarists. Sandbeds on reefs have the advantage of a constant import of larvae from other parts of the reef. A larger shallower bed would probably be a step in the right direction.

scale is always an issue. ask any wastewater treatment plant operator. why have it around anyway if you do not need it? siphon it out, then export it a larger waste processing facility?

Not clear as to your meaning. Do you think sand beds, skimmers and water changes are:
"sna ke oils corpoirate Amercia is pushing down the hobbyist throat"?

I agree there is no standard way to enjoy the hobby .

nope, none of those, but the way they are explained to work, can be. if they worked as advertised, then why are there so many other devices used to control nutrients?

How does it impact the corals and not get into the water column?

because it is in the system. how can something in the system not affect the organisms that are there? it is going to be taking away resources. whether it is space or elemental resources. everything we put into our systems affects the organisms that are in it.

we seem so obsessed with what goes into our systems, yet we do not put the same degree of obsession to what goes out of our systems.

G~

 

[Randy Holmes-Farley]

lbecause it is in the system. how can something in the system not affect the organisms that are there? it is going to be taking away resources. whether it is space or elemental resources. everything we put into our systems affects the organisms that are in it.

we seem so obsessed with what goes into our systems, yet we do not put the same degree of obsession to what goes out of our systems.

G~

Are you seriously asking how something can be in the system and not cause a problem?

A living fish is a ticking time bomb of nitrogen and phosphorus. Is that the conclusion you reach considering a fish?

I presume that you agree that the entire time it is alive, the nitrogen and phosphorus in its tissues are not causing a problem for the tank.

QED: one can have huge stores of nutrients in reef tanks without there being a problem.

 

[Amphiprionocellaris]

there is something fundamentally different in the home aquarium than in nature, that is what i have been trying to say. in nature the substrates are disturbed on a regular basis. sometimes every tide. our puny little 4" substrates are nothing compared to the amount of movement of a substrate in on those reefs that have them. when tropical storms come through, the substrates can be disturbed several feed down. this is a fundamental difference between what is going on in nature and what we are told to do in our home systems. WHY? this is probably the biggest point i have been trying to make. substrates in nature are "siphoned" clean regularly. the built up waste organic material is washed away and the benthos is allowed to rebuild in relatively waste free environment.

No we don't have the scale of disturbance that is seen on the reef, but that's not what I was talking about. I was talking about the buildup of refractory organic matter, and the time scales it would take to "clog" a sediment based on its slow accumulation. If labile OM is accumulating, and it's at faster rates than in nature, that's where the fundamental difference comes in, because a healthy sand bed should not experience such buildup; the labile portion is broken down rapidly so that it cannot accumulate long term. If you want to focus on the physical disturbance, that's fine too, but you can't ignore the biological role as well.

and how is this not what i have been saying the entire time? we must clean up after our pets on a regular basis. get the build up of waste organic material out of the substrate so that the benthos have more room again. just flushing the toilet or taking out the trash.

Again, the buildup that you're talking about necessary to clog up the sediment takes place over decades. The vast majority of waste OM that ends up in the sediment is rapidly remineralized and removed in one form or another (if the sand bed has a healthy population).

think of the "overall content" as potential P. the greater the total P the greater the chance of all of that P being released back into the water column at a rate faster than the system can handle. either from die off, disturbing of the substrate without siphoning the material, rock slides, powerhead getting dislodged or falling into the substrate, the list can be infinite. it is just keeping the total amount of P as low as possible to maintain the must have organisms.

G~

That's one way to approach husbandry, of course, but that's really a general statement that applies to all reefs: corals, fauna in the live rock, all the extra fauna like clean up crews, fish, etc, all represent "potential P", so this isn't something that's exclusive to sand beds. If you want to reduce the total amount of biomass by removing one part of the system and replace its role with active, physical removal, there's nothing wrong with that. But it's not necessary, and it's much more hands-on than some aquarists like to be.

 

[saf1]

Not clear as to your meaning. Do you think sand beds, skimmers and water changes are:
"sna ke oils corpoirate Amercia is pushing down the hobbyist throat"?

I do. They are just another tool in the shed that a hobbyist can use. They are not required to make a successful reef just like MH, LED's, bare bottom, DSB, or any other combination thereof.

There are people that change a percentage of water daily, others weekly, some bi, others has little has 2 to 4 times a year. Others that believe they need to add X chemical while others Y. Then talk about terrestrial food, native, non native. What fish can be kept in what size aquarium, what can't, what is difficult, not difficult, etc. Who am I to say what is right or wrong?

Running a DBS != failure no more than running a bare bottom = success. What matters is the hobbyist consistency and ability to learn from mistakes. One thing that will guarantee failure is ignorance. I'd put that in bold if I knew how to format it correctly