Weekly Discussion - BB vs DSB

[Anonymous]

Russ,

Nice to see you over here!

Part of the problem we are running into here is that the proponents of Dr style DSBs never show any proof of their theories. They said it was out there, but no one can seem to find it. When people went digging, the papers they found all seem to support the idea that sand bed is in effect a sponge. I am being convinced of the superiority or BB or LSB (lil' sand bed - term coined here, the apostrophe must be used :mrgreen: ) in great part by the idea that not only is there no support for the idea of a Dr style DSB, but that the research actually shows that they don't work. This seems to trump anecdotal hypothesis.

Like Galleon pointed out, more life in the sandbed is suspect. The broader food web you talk of also means a higher bio load, and more waste to sit in the tank, and more mouths to feed. And, there seems to be little evidence that sandbeds produce plankton that corals eat - sounds like a good idea, but no support.

A sand bed is both a 'sink' and a habitat. The question is does the habitat outweigh the sink in regards to usefulness, and is it worth the maintenance required.

I agree with you about the fertile dirt idea. In fact, I stir my tank on a regular basis (I think I may do it more often now) to export ickies.

 

[Anonymous]

Hmmm. If DSB are filling up, why not solidify them (inject kalk) in place from the bottom up?

 

[RustySnail]

You know... Adding the 'm' word to a person's post when stated 'strictly hypothetical' is really unfair. Where do you start looking at a problem and developing a solution without some hypothesis of what is happening in a system? Doing journal research that is in areas that point to whatever answer you want is not the correct way to prove something. You have to look at different theories and hypotheses and determine by doing some pretty serious testing to determine what is going on.

From what I have read on various discussion forums is that a mountain of semi-related research papers have been read and based on this the answer is that DSB's are not viable. Well that's not a proper scientific answer either. It's a mythical answer based on deductive reasoning; wich is NOTT scientific. All I offered in what I had written was a hypothesis of what we might be seeing is happening in our tanks; and some 'potential' ways to mitigate the problem. To prove it or any other hypothesis (weather deduced or reasoned) you need to do some serious testing; (like doing bulk analysis of a DSB that is healthy and one that is leaching nutrients; and at points inbetween); and that has not been done yet.

 

[RustySnail]

The broader food web you talk of also means a higher bio load, and more waste to sit in the tank, and more mouths to feed.

No... Those sandbed 'mouths to feed' are not being actively fed. They are consuming food that could not be captured by corals and other sessile life forms; and detritus that escapes other detritus eating organisms. They do not add to system bio-load; they are free nutrient re-cyclers. Skimmers can only capture a percentage of the organic matter that is put into an aquarium; the rest must be utilized by bio-uptake. And recall that in order to be fully utilized, raw food protiens must be eaten more than 10 times to be fully reduced. How do you accomplish this without a large population of 'mouths' at the base of the food chain?

A sand bed is both a 'sink' and a habitat. The question is does the habitat outweigh the sink in regards to usefulness, and is it worth the maintenance required.

Well if you don't touch it and it will work fine for up to 4 years without the onset of problems; then some infrequent maintenance (storming/vacuuming) puts the DSB into the category of 'very low maintenance' IMHO. Not to say would not be a big job in a 400g tank; but overall cost/maintenance gets much higher with tanks that big anyway.

I agree with you about the fertile dirt idea. In fact, I stir my tank on a regular basis (I think I may do it more often now) to export ickies.

Thanks... But still, just non-scientific theory....

 

[Anonymous]

You know... Adding the 'm' word to a person's post when stated 'strictly hypothetical' is really unfair.

Not sure what 'm' word you are talking about.

Where do you start looking at a problem and developing a solution without some hypothesis of what is happening in a system? Doing journal research that is in areas that point to whatever answer you want is not the correct way to prove something. You have to look at different theories and hypotheses and determine by doing some pretty serious testing to determine what is going on.

But Russ, the hypotheses re Dr style DSB's you presented aren't new, they have been talked about for years, and there seems to be no support for them in any of the literature - even though we have been told again and again that there is.
The journal research that has been been presented in reef forums was not done for the hobby, rather, it was done by people doing their own thing - so it isn't pick and choose science to support the answer wanted. And there doesn't seem to be any journal research that supports the answer that you want.
Perhaps it is the case that sand beds act differently in aquariums than they do in nature, and it would behoove us if someone did a real study on them, however until that happens the evidence against them seems pretty strong -'specially since we were told the evidence in support of them is out there and no one can find it.
Remember, Dr style DSB's were promoted in exactly the way you describe above; unsupported theory with no science to back it up.

From what I have read on various discussion forums is that a mountain of semi-related research papers have been read and based on this the answer is that DSB's are not viable.

I think that is an incorrect conclusion that people are reaching. What I think is correct is that it looks like Dr style DSB's cant work like we have been told, and that sand is a nutrient sink even in nature. That there are 'microclimates' in all areas of the sand rather than distinct levels. And that once sand is saturated, it will re release back into the water. This is not to say that sand is not viable, rather that there are issues related to sand that must be dealt with if you are running a system with sand.
It not that they are no viable (I think that position is being taken by many for personal reasons), it that they can't work the way we have been told they work.

Well that's not a proper scientific answer either. It's a mythical answer based on deductive reasoning; wich is NOTT scientific.

I don't know about that. The studies are pretty conclusive about what is going on in sand in nature. Can those studies be applied to sand in our tanks? Prolly. I don't really see a reason to think sand would act much differently in our tanks.
However, I do find much of the sand science lacking in details that would be helpful to reefers. We don't know how fast phosphate can build up, we don't know how quickly it can be released, we don't know if it necessarily will be released, and we don't really know how deadly it is or in what amounts it is.

All I offered in what I had written was a hypothesis of what we might be seeing is happening in our tanks; and some 'potential' ways to mitigate the problem.

The mitagation ideas were great, however, the hypothesis presented have been floating around in the hobby for a long time, and there doesn't seem to be any support for them.

To prove it or any other hypothesis (weather deduced or reasoned) you need to do some serious testing; (like doing bulk analysis of a DSB that is healthy and one that is leaching nutrients; and at points in between); and that has not been done yet.

I would like to see such testing done as well.

 

[Anonymous]

The broader food web you talk of also means a higher bio load, and more waste to sit in the tank, and more mouths to feed.

No... Those sandbed 'mouths to feed' are not being actively fed.

I never said they had to be actively fed - that is something from one of the other threads. What about my other points?

They are consuming food that could not be captured by corals and other sessile life forms; and detritus that escapes other detritus eating organisms. They do not add to system bio-load; they are free nutrient re-cyclers.

To a point. They don't recycle everything, they simply cant, and they produce their own wastes that aren't recycled. The science is pretty clear about this. Well, those wastes are recycled when the sand releases them by cyano and hair, but people don't enjoy that.

Skimmers can only capture a percentage of the organic matter that is put into an aquarium; the rest must be utilized by bio-uptake.

Or it stays in the sand until the sand can hold it no longer.

And recall that in order to be fully utilized, raw food protiens must be eaten more than 10 times to be fully reduced. How do you accomplish this without a large population of 'mouths' at the base of the food chain?

You don't, and I don't think you can with a large population of 'mouths' either. In nature when the sand fills up you get algae blooms, while in our tanks we are trying to avoid this.

Well if you don't touch it and it will work fine for up to 4 years without the onset of problems;

You won't get an argument from me here. What a great filter that works for 4 years or so with no maintenance.
Again, most of the attacks on sand seem to be more personal. Sand works great for almost everyone for 2-4 years. That is awesome. Then something has to be done, or something has to be done all along. The personal part also includes having to do something drastic to a mature tank because the sand is 'full'.

then some infrequent maintenance (storming/vacuuming) puts the DSB into the category of 'very low maintenance' IMHO.

I think I disagree with you here. I would be scared of stirring up a sand bed that had been sitting undisturbed for 4 years. I think the chance or putting large amounts of poisons into the water would be high.

Not to say would not be a big job in a 400g tank; but overall cost/maintenance gets much higher with tanks that big anyway.

Agreed. If I were setting up a new big system, I would minimize the sand.

 

[Anonymous]

Most of the corals hobbyists label as “SPS” are farmers. They can rely wholly on what their zooxanthellae produce and take up trace amounts of nitrogen and phosphorous from both their symbiont’s metabolism and the water column to translate and transcribe proteins. They also culture bacteria by trapping suspended particulates. None of these “SPS” are adept at capturing the kinds of plankton that spawning and DSB infauna or epifauna would hypothetically be producing.

Not to get off track too much, but are you sure about this? Polyps don't seem to be the ideal morphology for the above tasks. And, the Acropora in my tank visibly take food readily....

 

[Anonymous]

Well, Rich covered a lot of important points in his responses to RustySnail.

Doing journal research that is in areas that point to whatever answer you want is not the correct way to prove something.

Rusty, I’ve got no agenda against DSB’s. There is just nothing peer reviewed that contradicts the sources I’ve brought up. I’m not cherry picking between pro and con articles to support a position.

From what I have read on various discussion forums is that a mountain of semi-related research papers have been read and based on this the answer is that DSB's are not viable. Well that's not a proper scientific answer either. It's a mythical answer based on deductive reasoning; wich is NOTT scientific.

The actual phenomenon of regeneration is so well documented in almost any marine sediment type you could pull out of the hat that it would laughable to assume that a more intensely loaded sink didn’t do the same.

The only difference between several of the examples that are presented in peer reviewed and the closed hobbyist DSB systems is the higher rate of phosphorous loading on the sink with limiting amount of substrate for bacterial culture. That’s not mythical, that’s logic. It’s been done on closed systems; specifically, for the Florida Bay crash projects. If you read the earlier posts on this thread, you’ll find that I already covered this.

To prove it or any other hypothesis (weather deduced or reasoned) you need to do some serious testing;

Hypotheses are never proven. Tested, yes; supported or negated, yes; proven, no.

No... Those sandbed 'mouths to feed' are not being actively fed.

But they are. Trapping particulates and nutrients is what is actively feeding them.

Eliminate the crap being sunk = eliminate the active food source = eliminate the bioload = eliminate the nutrients being regenerated by the bioload.

Not to get off track too much, but are you sure about this?

Yes. Any non-hobby based synthesis on coral biology/ecology or peer reviewed paper on coral nutrition will say such.

Not sure what 'm' word you are talking about.

I think he meant my reference to the word “myth”. However, this is not unfair, nor is it unwarranted. Much of what was in Rusty’s post was a direct falsehood perpetuated by what seems to be a significant percentage of the hobby.

 

[Anonymous]

It is usually at this point in the discussion that somebody snaps and gets angry. So, I will point out that taking somebody's opinion to task is not the same as attacking the person.
I know no one here would make that mistake, but its good to point it out from time to time.

:mrgreen:

 

[Anonymous]

DanConnor wrote:
Not to get off track too much, but are you sure about this?


Yes. Any non-hobby based synthesis on coral biology/ecology or peer reviewed paper on coral nutrition will say such.

Well, I don't have access to those, but my Marine Bio textbook (Levinton '95) says stuff like "hematypic corals, however, capture small animals by the use of their tentacles and nematocysts" and "carbon received from symb zoox must be supplemented by nitrogen, which usually comes from feeding on zooplankton" and the like....

 

[Anonymous]

DanConnor wrote:
Not to get off track too much, but are you sure about this?


Yes. Any non-hobby based synthesis on coral biology/ecology or peer reviewed paper on coral nutrition will say such.

Well, I don't have access to those, but my Marine Bio textbook (Levinton '95) says stuff like "hematypic corals, however, capture small animals by the use of their tentacles and nematocysts" and "carbon received from symb zoox must be supplemented by nitrogen, which usually comes from feeding on zooplankton" and the like....

The easiest thing (least metabolically expensive) to do is to take up dissolved nitrogen, phosphorous and free amino acids. Nematocysts are metabolically very expensive to make and they aren't reusable. There would be no reason to use them if they are obtaining the nutrients they need from a less expensive means (antiport of dissolved nutrients). The food intake you see your corals doing is triggered and involuntary. Nematocysts are sensitized to fire based on certain amino acid cues.

Based on the studies I've read, there should be more than enough dissolved nitrogen and phosphorous in closed systems to supply the N : P uptake of corals. Sometimes and in some locations the concentrations are too limiting to rely on completely in the wild, and many hermatypic corals then fall back on farming bacteria in particulates captured in mucus (they can also rely on it to build up lipid fractions to use as energy for gametogenesis even when there is enough DIN and DIP available). My guess is that this was explored after your textbook was published. Also, depending on the target level and major of the text, the book itself could be suspect. Professors report errors to publishing companies all the time. For the most part, many scleractinian polyps just aren't well acclimated to catching and efficiently utilizing zooplankton.

 

[Anonymous]

That, and it's damn hard to watch them feed on bacteria.

 

[DonJasper]

Boy reef keepers carry on vacuous debates. :roll: When arguing politics there's at a minimum of information. What’s kinda funny is Podman brings up the one and only measure of reef keeping – and it’s so EASY to objectively measure. Despite this, only Dr. Shimeck has so far accomplished it, and only then half-heartedly. 8O

Until someone does a test with two identical tanks, with the only variation being DSB and BB in which they are run for several years

The bottom line is that closed system models have demonstrated over and over again that phosphorous release does occur from a sediment sink. It’s better than anecdotal, too: it’s peer reviewed and a victim of the scientific process. Better yet, this information is easily obtainable in any marine chemistry textbook.

Then would someone, anyone, PLEASE present a number.
DSB this –versus- BB that. It should be easy. It seems not to be.

I think there are two reasons for this lack. One, if there is any performance difference between the techniques then it is too small to be measured. Two – there simply isn’t any information.

For what its worth, I think its more worthwhile to emulate the conditions of other successful reef tanks than the conditions on a real reef.

Agreed, to a point: success is subjective.

I disagree with both of you. Not only is success objective, but also easy to measure. Growth. Crop yield. Measured by weight gained, or increased volume displaced, number of baby sea urchins alive or dead, you figure it out. Personally I’d accept before and after pictures and draw my own conclusions.

*** WARNING *** My rant continues, and grows. If this upsets you, please realize that it's not directed to any individual - despite picking on Dan Conner twice. That was just a coincidence. This is not intended as a flame. If you feel the need to treat it as such, and flame back I beg you reconsider. *** WARNING ***

I don't understand why there's been no product reviews. Line them up side by side - salt mix, lighting whatever. Plunk down some Xenia. Take some snaps. And then keep taking pics once a month until it's clear which is the winner(s). Then I'd have some information that would be remotely useful in making a purchasing decision. Needless I can’t wait for the Inland Reef Salt Study to help me grow my sea creatures.

 

[Anonymous]

Boy reef keepers carry on vacuous debates. :roll:

This is the Weekly Discussion. The point of it is to open to discussion things that may not get discussed in depth during the regular day to day posting on this board.

When arguing politics there's at a minimum of information. What’s kinda funny is Podman brings up the one and only measure of reef keeping – and it’s so EASY to objectively measure.

I am not sure what you are referring to, and am not sure why you think this discussion to be vacuous.

Then would someone, anyone, PLEASE present a number.
DSB this –versus- BB that. It should be easy. It seems not to be.

The numbers you are looking for are not at all easy to get, and getting them is further complicated by the fact that everyone's system is different. Not to mention testing for phosphates is hard, and even harder to test for it in the sand.

I think there are two reasons for this lack. One, if there is any performance difference between the techniques then it is too small to be measured. Two – there simply isn’t any information.

Agreedish. People have experienced crashes in tanks with Dr style DSB's, and without such sand, that kind of crash couldn't happen in a BB. There is lots of related information that can be applied to our hobby, but there aren't any numbers specific to our hobby.

I disagree with both of you. Not only is success objective, but also easy to measure. Growth. Crop yield. Measured by weight gained, or increased volume displaced, number of baby sea urchins alive or dead, you figure it out.

Isn't that kind of a cop out? Its easy but you can't tell us what it is? :wink: If you feel that success is so easy to objectively measure, please let us know what constitutes success. Personally, I think it is easy to measure success, the hard part is getting everyone to agree what constitutes success. Much time is spent in science, industry and all business defining success, and usually that definition is limited to a specific part of a process.

Personally I’d accept before and after pictures and draw my own conclusions.

Then the information is out there. Lurk the different boards and you find many threads discussing tanks having problems due to Dr style DSB's. The problem is that some tanks with sand have problems and some don't, so the before and after pictures really only pertain to the individual example. However, you should easily be able to find before and after pictures of tanks with sand beds that have, and have not 'crashed'.

*** WARNING *** My rant continues, and grows. If this upsets you, please realize that it's not directed to any individual - despite picking on Dan Conner twice. That was just a coincidence. This is not intended as a flame. If you feel the need to treat it as such, and flame back I beg you reconsider. *** WARNING ***

I think if you feel the need to write such a disclaimer we would all be better served if you rewrote your post after you calmed down from your rant. Rants are nice, by a calm measured discussion is more 'successful'. :mrgreen: Oh, and not using a rolleyes emoticon after you first sentence would help too. :wink:

I don't understand why there's been no product reviews.

Because they cost money and no one has seen fit to sponsor such reviews or get grants to conduct them. As you know, Inland Reef does some, and maybe others will follow their lead.

Line them up side by side - salt mix, lighting whatever. Plunk down some Xenia. Take some snaps. And then keep taking pics once a month until it's clear which is the winner(s). Then I'd have some information that would be remotely useful in making a purchasing decision.

I think you should run the tests. We would all love to see the results. :mrgreen: Or if you want to financially sponsor the test, I would run it for you. :wink:

Needless I can’t wait for the Inland Reef Salt Study to help me grow my sea creatures.

Me too (though I am confused why you don't just look at before and after pictures of tanks that use different salt mixes :wink: ). But remember, that study came into existence because people couldn't agree what 'success' was in the Dr Ron study, and there has been a whole bunch of 'issues' regarding the methodology, and the determination of what 'success' is in the IR study.

 

[Anonymous]

I will see firsthand which way is better for (me). my tank is back up and running identically to the way it was before with one exception there is no sand. Although I must confess my lighting will not be exactly the same.
_________________
Mercedes 220

 

[RustySnail]

Would someone mind explaining to me what is expected to happen when food is placed into a BB system? I can't see advantage of the raw food matter and waste from fish/corals, etc not having a place to be cosumed before it tuns over to ammonia. I also find it hard to believe that all food matter/waste that goes into the water column and is not consumed will come out of the tank in your skimmer. So where does all this 'stuff' that would otherwise slowly build up in a DSB go? How is it removed from the system before bactera break these items down into A/N/N and POP? What are the export method(s) to achieve near zero nitrate/phosphate that DSB systems provide during their 'golden years'? Also, how does Heavy Metal buildup factor into the equation? The good Dr had already predicted that 4 years would be the max for your LR/LS if you are using salt mixes high in minerals; is problems that people are experiencing with DSB failure due to it 'filling up' or Heavy Metals?

Knowing that plankton, algae and bacteria blooms occur in nature (the ocean) regularly, no matter what climate/location; what makes us think that we can keep it from happening in a closed aquarium; no matter what kind of husbandry or system setup is used?

Galleon/other DSB nay-sayers... You win. I don't care to argue with you all ad-nauseum about DSB systems. They have been pretty fundamental at making SPS populated tanks viable; and well if they need to be replaced at 3-4 years or maintained regularly to keep them from building too much 'dirt' then OK I'll deal with it. But that's just me, I'm practically minded; I do what I see as best for my system and my enjoyment in this hobby; and it is NOT debating with those that think they have solved a problem without having tested for correlation of phenomena. Can I provide any better answers; no. Do I wish to go down the pathway of research to prove/disprove DSB viability; not feasible. Can I engineer a way to get beyond or avoid a problem; you bet.

 

[Anonymous]

Would someone mind explaining to me what is expected to happen when food is placed into a BB system? I can't see advantage of the raw food matter and waste from fish/corals, etc not having a place to be cosumed before it tuns over to ammonia.

It gets exported by the skimmer before it has a chance to break down. BB should have massive flow - to keep detritus in suspension - and good wet skimming to remove it.

I also find it hard to believe that all food matter/waste that goes into the water column and is not consumed will come out of the tank in your skimmer.

We really are talking about a lot of flow in a BB system. So much that you couldn't keep sand on the bottom if you wanted to. Also, most bb systems are set up with not much rock with flow all around the rock. It is a very different set up when compared with the common 'rock wall' style of aquascaping. Its one of the aspects of BB that really seems to get glossed over in these discussions.

So where does all this 'stuff' that would otherwise slowly build up in a DSB go? How is it removed from the system before bactera break these items down into A/N/N and POP?

Massive flow, skimming, and a detritus trap in the sump.

What are the export method(s) to achieve near zero nitrate/phosphate that DSB systems provide during their 'golden years'? Also, how does Heavy Metal buildup factor into the equation?

See above and waterchangees.

The good Dr had already predicted that 4 years would be the max for your LR/LS if you are using salt mixes high in minerals; is problems that people are experiencing with DSB failure due to it 'filling up' or Heavy Metals?

No one knows. I must admit that I am skeptical of Dr Rons conclusions. We will know more as the Inland Reef salt study get underway. IIRC, not many of the 'big guns' agree with the idea of metal being a problem.
It may be the case that phosphate release and generation is effected by 'metals', but I haven't seen anything about it in the literature. Galleon may know more.

Knowing that plankton, algae and bacteria blooms occur in nature (the ocean) regularly, no matter what climate/location; what makes us think that we can keep it from happening in a closed aquarium; no matter what kind of husbandry or system setup is used?

Actually, avoiding such things should be pretty easy, but tedious. If you had access to good NSW you would do a 100% water change every day. Bing, all ickies flushed out of the system every day. We can export ickies - through water changes, skimming, and other filteration - while the ocean can only dilute it or move it around.
The reason to avoid those blooms is because they are generally ugly, and potentially dangerous the the animals in the tank.

Galleon/other DSB nay-sayers... You win.

I don't think there are any 'DSB nay-sayers' in this thread, 'specially Galleon. Most in this thread have been pretty reasonable. I think a good amount of polarization around this issue only exists because people keep saying it does.

I don't care to argue with you all ad-nauseum about DSB systems.

Then don't! :wink:

They have been pretty fundamental at making SPS populated tanks viable;[/quote]

I don't know if this is true. Do you have any links?
And if true, then all we are really talking about is the limitations of a 'DSB', and some of the correct or incorrect ideas on their workings.

and well if they need to be replaced at 3-4 years or maintained regularly to keep them from building too much 'dirt' then OK I'll deal with it. But that's just me, I'm practically minded; I do what I see as best for my system and my enjoyment in this hobby;

Great! :mrgreen:

and it is NOT debating with those that think they have solved a problem without having tested for correlation of phenomena.

I think that is an unfair assessment of the discussion in this thread, and that those feelings are more applicable to threads on other boards.

Can I provide any better answers; no. Do I wish to go down the pathway of research to prove/disprove DSB viability; not feasible. Can I engineer a way to get beyond or avoid a problem; you bet.

Great, I think most here would agree with you, wish you well in the process, and ask you to provide updates along with any insight you gain in keeping sand in your tank over the long haul. I am especialy interested because I am doing my own thing to make my 4 inch sandbed last over time.

 

[RustySnail]

I'm gonna kick this off by saying I have a 9 year old DSB and I have yet to encounter problems with it. I have rarely done water changes and have only minimally vacuumed the substrate bed once (about 5 years ago).

I've been in this hobby during (and before) BB was the methodology de jour, and from my personal experience, DSB tanks I've operated all have looked significantly healthier then BB tanks I've husbanded.

People's mileage may vary.

 

[Anonymous]

Russ, I don't understand your post quoting Len from earlier in this thread.

 

[RustySnail]

Just bringing attention to an important post on this thread. One person was brave enough to post that their 9 year old system with a DSB has functioned with no major problems. If I were interested in solving the 'riddle of nutrient cycling'; I would take a close look at his system, and try to determine if he has done something different than those who have had problems. It could be as simple as sand type/depth, maybe type of sea salt (since TM buildup is potential), feeding regimen, specimens kept, LS seeding method, water circulation, or maybe he has a nutrient export method that is different or improved. There has got to be a reason for success with a DSB; so looking at those tanks that have demonstrated it would be a good place to start.

His post was completely passed over in terms of asking about what might have achieved this. Can those who have continuously criticsed the proponents of DSB systems honestly say that they are non-biased when they pay no attention to such a prominent success story?