Removed my sandbed

[RobertoVespucci]

Righty, I want you to know I stayed up late reading that thread and looking up words like 'paucity.' You killed Blenny. You bastards.

Try that other thread!

Awww Jeez, Lois.

 

[Mighty Quinn]

Thanks for the link. I will read through it before posting any more threads. It looks a bit long, so it may take me a day or so.

Cool. Here is the other one:
http://reefcentral.com/forums/showthrea ... ublication

It should take you a week to read it! Try to ignore the fighting and just look at the info.

Hell, I'm still reading the first thread. It takes awhile since I have to look up so many of the words that Galleon uses. :wink:

The phosphate gets bound by bacteria, which is one of the benefits/problems of the sand, and which allows the bed to act as a sink.

Ok, I think that we are getting somewhere here. My understanding so far is that the phosphate is basically released into the water column or bound as insoluble phosphate compounds in the sand bed. If you are saying that the phosphate is fixed by bacteria in a form that can later be leached (or is "regenerated" the correct term) back into the water column, then here we have found a major difference in the rhetoric that has been bantered around.

If the sand wasn't a sink, there would be little utility to having it in the tank at all. The problem is when the bed can no longer sink the nutrients they get rereleased and then they get used by algae - mostly by whatever algae is closest which is nuisance algae. This is the classic 'DSB crash'. I think that is right and I am sure Galleon will correct it if I'm not!

As I understand it from Ron's articles, the sand bed is not supposed to work by being a sink. It is supposed to be a place where nutrients are processed to the point where they are either devoid of nutritional value or are released back into the water column. The proported utility of having the sand bed is that it efficiently processes nutrients into a soluble form by utilizing a wide variety of benthic infauna.

I should point out that if you read Ron's articles and postings on RC, you will find that he stresses the extreme importance of phosphate export. He strongly recommends maximizing phosphate export through protein skimming, macroalgae harvesting and removal of biomass such as fast growing Xenia.

It would be great if we could boil this debate down into a few key issues in this thread. The first key issue is the difference between how bacteria and benthic infauna process food. Let's say that I give a piece of food to a sand bed colonized by bacteria only, and I give a second (but similar) piece of food to a sand bed that is heavily loaded with a diverse population of benthic infauna in addition to the bacteria. What are the differences between how the food is processed and how the components of the food are exported from these two sand beds?

No problem - maybe we can distill all this down in this thread!

That would indeed be fantastic.

 

[RobertoVespucci]

Honestly, I don't see how the little critters in the sand bed factor into the equation that much. Everything you add foodwise (that isn't skimmed out) gets digested by bacteria ultimately anyway, right? Regardless of how many intermediates contribute to the increase in entropy, the bacteria make up the difference don't they?

So . . . I wonder, does live rock sink the way sand does? I'm only on page 4 of the long-o thread, maybe that is answered later.

 

[RobertoVespucci]

Honestly, I don't see how the little critters in the sand bed factor into the equation that much. Everything you add foodwise (that isn't skimmed out) gets digested by bacteria ultimately anyway, right? Regardless of how many intermediates contribute to the increase in entropy, the bacteria make up the difference don't they?

Sorry to quote myself, but it occured to me that from a thermodynamic standpoint, s**t rolls downhill.

 

[Anonymous]

Ok, I think that we are getting somewhere here. My understanding so far is that the phosphate is basically released into the water column or bound as insoluble phosphate compounds in the sand bed. If you are saying that the phosphate is fixed by bacteria in a form that can later be leached (or is "regenerated" the correct term) back into the water column, then here we have found a major difference in the rhetoric that has been bantered around.

I believe 're released' is the term. Unfortunately, the mechanisms that cause a re release are not well understood.

As I understand it from Ron's articles, the sand bed is not supposed to work by being a sink. It is supposed to be a place where nutrients are processed to the point where they are either devoid of nutritional value or are released back into the water column. The proported utility of having the sand bed is that it efficiently processes nutrients into a soluble form by utilizing a wide variety of benthic infauna.

Sure that is what Ron says, however he just says it and provides no evidence and cites no papers to support that idea. As it turns out, so far no one has been able to find any study that supports that idea. Ron has said that there is such an article, but that it is up to us to find it. No one has been able to.

I should point out that if you read Ron's articles and postings on RC, you will find that he stresses the extreme importance of phosphate export. He strongly recommends maximizing phosphate export through protein skimming, macroalgae harvesting and removal of biomass such as fast growing Xenia.

Then I don't really see why we should bother with sand beds!

It would be great if we could boil this debate down into a few key issues in this thread. The first key issue is the difference between how bacteria and benthic infauna process food. Let's say that I give a piece of food to a sand bed colonized by bacteria only, and I give a second (but similar) piece of food to a sand bed that is heavily loaded with a diverse population of benthic infauna in addition to the bacteria. What are the differences between how the food is processed and how the components of the food are exported from these two sand beds?

I don't know. I think the first issue is any study backing up Rons claims. It really seems that he just thought it up.
And we haven't gotten to the idea that there are very few corals anywhere near sand and that sand beds are lagoonal, not coral 'reefal'. Also, sand near reefs just doesn't seem to have the infauna that Ron says we should have and keep paying for.

 

[Mighty Quinn]

I should point out that if you read Ron's articles and postings on RC, you will find that he stresses the extreme importance of phosphate export. He strongly recommends maximizing phosphate export through protein skimming, macroalgae harvesting and removal of biomass such as fast growing Xenia.

Then I don't really see why we should bother with sand beds!

I have to be careful that I don't get us buried in a circular debate here. My understanding of the DSB theory is that the critters in the sand process the phosphates so that they are either A.) insoluble and no bioavailable; or B.) soluble and go into the water column, where they are then exported by the mechanisms listed above. The correlary to this theory is that a sand bed populated by only bacteria would not process the phosphate in the same way. I think that this is the heart of the matter.

Unfortunately, I do not have enough background in this area to be able to prove this one way or the other. In my searching on the web for information, I did come across a good thread on phosphorus on Reef Frontiers:

http://www.reeffrontiers.com/forums/sho ... eadid=2672

Maybe after I finish reading this thread I will understand the phosphate issue better.

 

[Anonymous]

Ok, I think that we are getting somewhere here. My understanding so far is that the phosphate is basically released into the water column or bound as insoluble phosphate compounds in the sand bed. If you are saying that the phosphate is fixed by bacteria in a form that can later be leached (or is "regenerated" the correct term) back into the water column, then here we have found a major difference in the rhetoric that has been bantered around.

I believe 're released' is the term. Unfortunately, the mechanisms that cause a re release are not well understood.

pardon my ignorance Righty... i haven't been keeping up with the sand bed controversy lately, is there solid evidence that supports a rerelease will occur?

As I understand it from Ron's articles, the sand bed is not supposed to work by being a sink. It is supposed to be a place where nutrients are processed to the point where they are either devoid of nutritional value or are released back into the water column. The proported utility of having the sand bed is that it efficiently processes nutrients into a soluble form by utilizing a wide variety of benthic infauna.

Sure that is what Ron says, however he just says it and provides no evidence and cites no papers to support that idea. As it turns out, so far no one has been able to find any study that supports that idea. Ron has said that there is such an article, but that it is up to us to find it. No one has been able to.

I should point out that if you read Ron's articles and postings on RC, you will find that he stresses the extreme importance of phosphate export. He strongly recommends maximizing phosphate export through protein skimming, macroalgae harvesting and removal of biomass such as fast growing Xenia.

Then I don't really see why we should bother with sand beds!

you used too!

It would be great if we could boil this debate down into a few key issues in this thread. The first key issue is the difference between how bacteria and benthic infauna process food. Let's say that I give a piece of food to a sand bed colonized by bacteria only, and I give a second (but similar) piece of food to a sand bed that is heavily loaded with a diverse population of benthic infauna in addition to the bacteria. What are the differences between how the food is processed and how the components of the food are exported from these two sand beds?

I don't know. I think the first issue is any study backing up Rons claims. It really seems that he just thought it up.
And we haven't gotten to the idea that there are very few corals anywhere near sand..[snip]

i don't know, there are quite a few corals that i have seen that are very close to natural sand beds. i don't dive but keep a keen eye when watching cousteau :wink:
often i spy them every bit as close as we keep them in our sandbed aquariums.
regardles, i think we would both agree that this means little as a reef has such vast gallonage.
even still, there are some inverts that fair best on a sandbed.. clams like gigas, tongue coral, many swear that trachyphillia does better there, LTAs, and so forth.

[/snip].. and that sand beds are lagoonal, not coral 'reefal'. Also, sand near reefs just doesn't seem to have the infauna that Ron says we should have and keep paying for.

sorry, lagoonal as in what? do you mean, not the area that you would find lagoonal corals (brains, ancora, etc.) but more like a sheltered bay?



i think that many aquarists, add Dr Ron if you like, got carried away in the 'mimic nature' viewpoint. i don't knwo that he ever really thought that total mimicery (sp?) would result in success.
i haven't read a lot of Dr Ron but what i have read always had some sort of disclaimer attached somewhere or i interpretted it as opinion as i read it.
when i read how much life he felt should be added to a captive sandbed, i never considered that he was trying to mimic numbers that occured in nature, more that he was giving guidelines for what he found to be necessary to best perform the task in our very different captive environments.
but then, i never read his writings like a manual as some do.
the same can be said for my view of Bornemans opinions... he really had a following for a year or two with the mega sandbed, skimmerless thing.
i have noticed that abstract discussion in reefkeeping can be hazardous ...i think that both Dr Ron and Borneman have unwittingly displayed this.
... all these things are of course said with knowledge that i am not anywhere near as accomplished as these two aquarists are.

 

[Anonymous]

I have to be careful that I don't get us buried in a circular debate here. My understanding of the DSB theory is that the critters in the sand process the phosphates so that they are either A.) insoluble and no bioavailable; or B.) soluble and go into the water column, where they are then exported by the mechanisms listed above. The correlary to this theory is that a sand bed populated by only bacteria would not process the phosphate in the same way. I think that this is the heart of the matter.

That is the heart of the matter, and there is no data that shows that that is what actually happens. It sounds good, but the only support it has is that people keep saying it, not that it has been tested. It is a great theory, but it looks like it isn't how things actually work. FWIU, it is mostly the bacteria that process the phosphate, and I am unsure how the critters in the sand are supposed to help instead of just being more biomass.

 

[Anonymous]

pardon my ignorance Righty... i haven't been keeping up with the sand bed controversy lately, is there solid evidence that supports a rerelease will occur?

Yes. Not in tanks (it appears no one actually does studies on tanks), but in the wild. Look for FL blackwater events.

Then I don't really see why we should bother with sand beds!

you used too!

Shaddup you!
There are reasons to bother - animals that need it, if you like it - but not for filtration!

i don't know, there are quite a few corals that i have seen that are very close to natural sand beds. i don't dive but keep a keen eye when watching cousteau :wink:
often i spy them every bit as close as we keep them in our sandbed aquariums.
regardles, i think we would both agree that this means little as a reef has such vast gallonage.
even still, there are some inverts that fair best on a sandbed.. clams like gigas, tongue coral, many swear that trachyphillia does better there, LTAs, and so forth.

There are bunches of animals that live in/on the sand, but the bulk of the corals we keep don't.

Look at a few pics of reefs in the wild, the vast majority of the coral is no where near the sand. If you find good pics, post em here. I have a couple I will try to put up today.

sorry, lagoonal as in what? do you mean, not the area that you would find lagoonal corals (brains, ancora, etc.) but more like a sheltered bay?

No, you got it. Most of the corals we keep are not from those areas.

i think that many aquarists, add Dr Ron if you like, got carried away in the 'mimic nature' viewpoint. i don't knwo that he ever really thought that total mimicery (sp?) would result in success.

And the mimicry isn't even accurate!

i haven't read a lot of Dr Ron but what i have read always had some sort of disclaimer attached somewhere or i interpretted it as opinion as i read it.

IME he doesn't act like its only opinion.

but then, i never read his writings like a manual as some do.
the same can be said for my view of Bornemans opinions... he really had a following for a year or two with the mega sandbed, skimmerless thing.
i have noticed that abstract discussion in reefkeeping can be hazardous ...i think that both Dr Ron and Borneman have unwittingly displayed this.
... all these things are of course said with knowledge that i am not anywhere near as accomplished as these two aquarists are.

I think you are! I have major distrust for anyone who believes their own press and gives themselves 'rock star' status.

 

[Anonymous]

google "lagoon"= 1st pic

 

[Anonymous]

 

[polcat]

Great discusion. On the RC boards Ron and Bomber had this same discusion, very lengthy. Bottom line I came away with was a quote from Bomber " marine sediments act like marine sediments whether in a tank, a lagoon, or the ocean" and the ocean has been studied with respect to phosphates. The FL blackwater (seasonal)event and most probably DSB events are triggered by a Ph change (between areobic/anerobic areas) that allows bacteria to rerelease phosphate into the water column. Notice critters are not mentioned. That's what some of the research indicated anyway, I can dig it up if anyone is interested.

Side note; if you take a piece of live rock and put it in complete darkness, do weekly water changes for a month, what happens. The algae dies, bacteria takes over and consumes all the phosphates stored in the rock. The bacterial tugor will push all the processed nutrients out of the rock. You now have a bacteria driven system not algae driven. Put that rock back into a lighted aquarium and algae will not grow on it. Now feed it, the bacteria will process the phosphates until it is overwhelmed then algae takes over again. Nonrelevant? Maybe...

 

[Anonymous]

Marked for archiving

 

[Mighty Quinn]

I have to be careful that I don't get us buried in a circular debate here. My understanding of the DSB theory is that the critters in the sand process the phosphates so that they are either A.) insoluble and no bioavailable; or B.) soluble and go into the water column, where they are then exported by the mechanisms listed above. The correlary to this theory is that a sand bed populated by only bacteria would not process the phosphate in the same way. I think that this is the heart of the matter.

That is the heart of the matter, and there is no data that shows that that is what actually happens.

Is there data that shows that it is not what happens? That is to say, is there any study that compares different nutrient processing mechanisms between sand beds with and without the benthic infauna? We have two conflicting claims here: one that the DSB is inherently a phosphorus sink, and another that claims that a properly setup DSB (a la Dr. Ron) will not become a sink. We need data one way or the other to sort this out. You can't say that one is right because there is no data supporting the other.

Galleon gave us a lot of good references for the regeneration of phosphates from various sediment beds. I am working on getting full versions of these references, but some of the older ones are difficult for me to get my hands on. Perhaps the data I seek is in these references. I am concerned that these studies may not accurately represent the DSB's in our tanks in one or more ways (type of nutrient input, amount of nutrient input, nutrient processing mechanism, etc...), but I really need to read the papers before I can pass judgement. Hell, I'm no biologist so even after I read the papers I cannot pass judgement.

I would really like to see some sort of flow chart that shows the different pathways that the various forms of phosphorus take in our tanks. I think that Mojoreef attempted to address this issue in the thread that I provided a link to in my previous post, but I think that a diagram showing the possible pathways would really be very educational. Anyone here care to take on that challenge? Galleon?

FWIW, I will bring up the issue of differences in nutrient process mechanisms (specifically for phosphorus) between DSB's with infauna and those with just bacteria on Ron's RC forum this weekend.

So, have we made progress yet?

Kindest regards,
Quinn

 

[Anonymous]

Is there data that shows that it is not what happens? That is to say, is there any study that compares different nutrient processing mechanisms between sand beds with and without the benthic infauna? We have two conflicting claims here: one that the DSB is inherently a phosphorus sink, and another that claims that a properly setup DSB (a la Dr. Ron) will not become a sink. We need data one way or the other to sort this out. You can't say that one is right because there is no data supporting the other.

AFAICT, there are no studies of sand beds in tanks at all. There is however plenty of studies of 'wild' sand, and those studies support the phosphorus sink idea. Even though Ron says the studies that support his ideas are 'out there', no one has been able to find one.

FWIW, I will bring up the issue of differences in nutrient process mechanisms (specifically for phosphorus) between DSB's with infauna and those with just bacteria on Ron's RC forum this weekend.

Do a search there first - I believe that those questions have been asked of Ron before.

So, have we made progress yet?

Tons! We aren't fighting about this, we are talking. We are looking for evidence, not just believing the party line.

 

[Anonymous]

so in regards to rock being renewable through "cooking" etc..

i wonder if an aquarist were to set up a DSB like plenum... that is elevated off the bottom inside this tank the bottom would be a 'drain pan' type of bottom with a drain pipe and valve on it.. i wonder if periodically this valve could be used as a "blow down".. to evacuate the settled funk?

 

[Anonymous]

Some people have been trying this. The consensus last time I checked was that it was a big old pain, it wasn't clear that any/enough detritus was being remove, and the question remained - if denirtification can be handled by the rock in the tank, why add the sand.

 

[polcat]

so in regards to rock being renewable through "cooking" etc..

i wonder if an aquarist were to set up a DSB like plenum... that is elevated off the bottom inside this tank the bottom would be a 'drain pan' type of bottom with a drain pipe and valve on it.. i wonder if periodically this valve could be used as a "blow down".. to evacuate the settled funk?

I have read of exactly that setup. The effluent was drained once a week and according to the author smelled of hydrogen sulfide. This person reported years of success with this method. I could research it if anyone wants more info??

 

[Anonymous]

so in regards to rock being renewable through "cooking" etc..

i wonder if an aquarist were to set up a DSB like plenum... that is elevated off the bottom inside this tank the bottom would be a 'drain pan' type of bottom with a drain pipe and valve on it.. i wonder if periodically this valve could be used as a "blow down".. to evacuate the settled funk?

I have read of exactly that setup. The effluent was drained once a week and according to the author smelled of hydrogen sulfide. This person reported years of success with this method. I could research it if anyone wants more info??

Here's a link to one guy who is doing exactly that:

http://www.saltwaterfish.com/vb/showthr ... did=116647

 

[Anonymous]

I guess if you did that quickly you could get rid of all the hydrogen sulfide. Oh yea they call that an under gravel filter. LOL.