Removed my sandbed

[Mighty Quinn]

They really need to be recharged with more sand critters periodicaly. You can't just throw 4" of sand in and forget about it...well you can but the effects will become apparent over time. When the DSB stops processing phosphates because it is full, you will know.

I don't buy the recharge the critters/properly maintain part of DSB methodology. You simply cant recycle 100% of the goo in a tank. Ron says you should replace your DSB every 5 years.

I don't think that it is a matter of the DSB getting full or recycling the goo. Based on everthing I have read on DSB's, there are sufficient export mechanisms to account for all of the inputs. I think that the issue is that some DSB's may stop working because the waste processing capability dimishes with time. The likely cause of this demise is insufficient infauna population or lack of sufficient biodiversity in the DSB.

Both population and diversity of the infauna have a tendency to decrease with time due to over predation and issues related to the finite size of our sand beds. Therefore, frequent innoculation of new infauna is likely an essential part of maintaining a functioning DSB. In my opinion, the difficulty is in figuring out how frequent these innoculations need to be. Obviously, it will be different for each individual tank because of variations in tank size, bio-loading, predation and numerous other factors that I could never quantify.

By the way, does Ron really advocate changing the DSB every 5 years? I don't recall reading that anywhere.

Kindest regards,
Quinn

 

[Anonymous]

I don't think that it is a matter of the DSB getting full or recycling the goo. Based on everthing I have read on DSB's, there are sufficient export mechanisms to account for all of the inputs. .

That is what Ron and others say, but they present no data to back up those claims. None. Not even when asked point blank. There is, however, a lengthy thread on RC that presents much data to support the 'fill up' idea.
The question is where do these sufficient export mechanisms export to?

I think that the issue is that some DSB's may stop working because the waste processing capability dimishes with time. The likely cause of this demise is insufficient infauna population or lack of sufficient biodiversity in the DSB.

Again, that is the common thought, but I can find no data actually showing that the infauna do what they are said to do - and I am not even sure how they are supposed to do what they are said to do.

Both population and diversity of the infauna have a tendency to decrease with time due to over predation and issues related to the finite size of our sand beds. Therefore, frequent innoculation of new infauna is likely an essential part of maintaining a functioning DSB.

We are told the infauna keep the bed turned, but not how they keep the DSB functioning - or if we are told its just someone saying so. What is a functioning DSB, and how do you tell? Sure the infauna seem to decrease over time, but until someone can show what these infauna do what they are supposed to do and how they export equal to the inputs, it seems to me that spending time and money on inoculations is just hoping it works.

In my opinion, the difficulty is in figuring out how frequent these innoculations need to be. Obviously, it will be different for each individual tank because of variations in tank size, bio-loading, predation and numerous other factors that I could never quantify.

Ron lays out how to check the infauna level of a sand bed, but it is not easy and needs to be done often.

By the way, does Ron really advocate changing the DSB every 5 years? I don't recall reading that anywhere.

I can't point you directly to it right now, but I believe it was in regards to his heavy metal toxicity ideas.

Kindest regards,
Quinn

 

[Mighty Quinn]

That is what Ron and others say, but they present no data to back up those claims. None. Not even when asked point blank. There is, however, a lengthy thread on RC that presents much data to support the 'fill up' idea.
The question is where do these sufficient export mechanisms export to?

Carbon based compounds are oxidized to carbon dioxide gas. Some of this carbon dioxide might be used by photosynthetic organisms, but the rest goes into the atmosphere.
Nitrogen based compounds are oxidized to ammonia, then nitrite then nitrate. Anaerobic bacteria reduce nitrates to nitrogen gas, which exits the water into the atmosphere. Some of the nitrates may get utilized by algae.
Soluble phosphates are removed from the water column by algae and protein skimming. Preferably this algae is macro algae that is being utilized as a mechanism for phosphate export. Some amount of phosphate can also be removed by water changes, although I think that this is probably not very effective for most tanks due to the low amount of dissolved phosphate in the water column at any given moment.

Of course, some of the carbon, nitrogen and phosphorus is fixed in the biomass of the tank inhabitants.

What did I miss?

Again, that is the common thought, but I can find no data actually showing that the infauna do what they are said to do - and I am not even sure how they are supposed to do what they are said to do.

I think that the infauna are simply supposed to eat and respire. They "exhale" CO2 and "pee" ammonia and phosphate. Ideally, anything that is left "uneaten" that would "clog" the sand bed is effectly so nutrient deficient that it would not or could not cause a system crash.

We are told the infauna keep the bed turned, but not how they keep the DSB functioning - or if we are told its just someone saying so. What is a functioning DSB, and how do you tell? Sure the infauna seem to decrease over time, but until someone can show what these infauna do what they are supposed to do and how they export equal to the inputs, it seems to me that spending time and money on inoculations is just hoping it works.

Great points and difficult questions for a non-biologist like me to answer. I have read many of Ron's articles, as well as many of the references that he sites. There does seem to be quite a bit of information on exactly what species live on and between sand grains, what they eat and what wastes they produce. Beyond that, I'm not sure what else to say.

We do agree on one point: if you don't want to spend the time and money maintaining a good population of infauna in your DSB, then you are better off choosing another viable reef tank philosophy.

Ron lays out how to check the infauna level of a sand bed, but it is not easy and needs to be done often.

Not to mention it is a pain in the ass! I mean, come on. I barely find time to keep up with tank maintenance as it is, let alone counting microscopic bugs under a microscope! Therefore, I err on the side of being conservative and introduce some new live sand or inoculation every couple months.

By the way, does Ron really advocate changing the DSB every 5 years? I don't recall reading that anywhere.

I can't point you directly to it right now, but I believe it was in regards to his heavy metal toxicity ideas.

Here's a quote that I found from one of Ron's posts on RC on the subject of changing sand beds:

If you set up a sand bed as normal (see the the "Sand bed questions" sticky thread at the top of the forum listings) and use a low metals salt, along with good nutrient export, I see no reason that a sand bed can't last indefinitely.

On the other hand if you have hermit crabs, and sand sifting stars and fish, it will may be somewhat functional for at least a few days. After that... nope.

So...

The functionality of a sand bed is dependent upon the animals in it. Hermit crabs, and sand sifting animals kill and eat those animals and simultaneously kill the functionality of the sand bed.

Bottom line is that the animals that make of the infauna in the DSB will eat anything that is rich in nutrients. They will "exhale" and/or "piss" out CO2, nitrogen compounds and phosphates. Nitrogen eventually leaves the system as a gas, or is fixed by algae. Phosphates are either removed by skimming or fixed by algae. Algae removal is an important part of nutrient export.

Please note that I do not want to portray myself as a DSB loyalist or a Shimek devotee. I like to think that I am unbiased and base my opinions on "facts" and known, established phenomena in biology. I have read many of the posts for and against DSB, as well as many articles (albeit, all of the "unbiased" articles I have read were sited by Shimek), but it really seems that all the mechanics for how and why a DSB should work are all there. However, I could be missing something really obvious that causes the entire mechanism to break down and stop working. I would welcome some good discussion on this point, since I currently have a DSB in a smaller tank, and I am planning on installing one in my next large tank sometime in the future.

Kindest regards,
Q

 

[Anonymous]

You think that's sparse you should see mine. don't worry about seeing the glass in front. Because in three to six months it will more than likely be pink.

 

[Anonymous]

Nitrogen based compounds are oxidized to ammonia, then nitrite then nitrate. Anaerobic bacteria reduce nitrates to nitrogen gas, which exits the water into the atmosphere. Some of the nitrates may get utilized by algae.

Only under a very specific set of conditions that DSB's can't provide long term.

Soluble phosphates are removed from the water column by algae and protein skimming. Preferably this algae is macro algae that is being utilized as a mechanism for phosphate export.

This is not the only, or even the major, pathway for P. It most definitely is NOT a desireable pathway either, as being able to support macroalgal productivity of this type is a telltale for eutrophication.

Some amount of phosphate can also be removed by water changes, although I think that this is probably not very effective for most tanks due to the low amount of dissolved phosphate in the water column at any given moment.

If you're at the point where you have discernable DIP that can be mitigated by water changes, you're Screwed with a capitol S.

Of course, some of the carbon, nitrogen and phosphorus is fixed in the biomass of the tank inhabitants.

Mainly bacteria, where it's constantly in flux. Where do you think all the detritus Righty was talking about comes from? It's bacterial flock that gets exported from the reef and sunk on abyssal plains. Physical removal is part of the game in reality, but aquarists who use DSB's seem to think it doesn't apply to them.

I think that the infauna are simply supposed to eat and respire. They "exhale" CO2 and "pee" ammonia and phosphate. Ideally, anything that is left "uneaten" that would "clog" the sand bed is effectly so nutrient deficient that it would not or could not cause a system crash.

Ecological rule of 10's. No way do you have or could you have enough infauna (more bioload, even) to consume detritus to the point of starving it of its nutritive content. Diminishing returns.

You just can't export it all ecologically. Even nature doesn't.

There does seem to be quite a bit of information on exactly what species live on and between sand grains, what they eat and what wastes they produce.

Where's this info at? Can you provide one with the nutritive content of their wastes?

Bottom line is that the animals that make of the infauna in the DSB will eat anything that is rich in nutrients. They will "exhale" and/or "piss" out CO2, nitrogen compounds and phosphates. Nitrogen eventually leaves the system as a gas, or is fixed by algae. Phosphates are either removed by skimming or fixed by algae. Algae removal is an important part of nutrient export.

That bottom line is a product of a lot of hyperactive imaginations and has little to do with reality.

 

[Fastmarc]

One thing I have learned in this hobby is that there are many different ways to successfully keep a reef tank. There is no one way to do it. What works for one person may not work for another (or vise versa) due to the suttle differences between tank and husbandry practices.
Seeing what works for different individuals is always very interesting and IMO is health dialog, but stating what works and what doesn't makes no sense. Understanding this hobby has changed so much in the last few years, I am sure we are still in for a lot more learning.
My 2c

 

[Anonymous]

Carbon based compounds are oxidized to carbon dioxide gas. Some of this carbon dioxide might be used by photosynthetic organisms, but the rest goes into the atmosphere.
Nitrogen based compounds are oxidized to ammonia, then nitrite then nitrate. Anaerobic bacteria reduce nitrates to nitrogen gas, which exits the water into the atmosphere. Some of the nitrates may get utilized by algae.
Soluble phosphates are removed from the water column by algae and protein skimming. Preferably this algae is macro algae that is being utilized as a mechanism for phosphate export. Some amount of phosphate can also be removed by water changes, although I think that this is probably not very effective for most tanks due to the low amount of dissolved phosphate in the water column at any given moment.

Of course, some of the carbon, nitrogen and phosphorus is fixed in the biomass of the tank inhabitants.

What did I miss?

Even if all that is true (see Galleon's post) none of it has anything to do with the infauna that Ron says you need for a healthy DSB.

I think that the infauna are simply supposed to eat and respire. They "exhale" CO2 and "pee" ammonia and phosphate. Ideally, anything that is left "uneaten" that would "clog" the sand bed is effectly so nutrient deficient that it would not or could not cause a system crash.

If that is all they do, then I don't see the point in having them. Let the bacteria do the work. I also think you'd be hard pressed to find data that shows their leavings are nutrient deficient.

Great points and difficult questions for a non-biologist like me to answer. I have read many of Ron's articles, as well as many of the references that he sites. There does seem to be quite a bit of information on exactly what species live on and between sand grains, what they eat and what wastes they produce. Beyond that, I'm not sure what else to say.

Yep!

We do agree on one point: if you don't want to spend the time and money maintaining a good population of infauna in your DSB, then you are better off choosing another viable reef tank philosophy.

Sure! And again, I still don't know what the infauna are supposed to be doing.

Here's a quote that I found from one of Ron's posts on RC on the subject of changing sand beds:

If you set up a sand bed as normal (see the the "Sand bed questions" sticky thread at the top of the forum listings) and use a low metals salt, along with good nutrient export, I see no reason that a sand bed can't last indefinitely.

On the other hand if you have hermit crabs, and sand sifting stars and fish, it will may be somewhat functional for at least a few days. After that... nope.

I think that is old, but I am not sure. There is a massive thread about this on RC if you can find it.

Bottom line is that the animals that make of the infauna in the DSB will eat anything that is rich in nutrients. They will "exhale" and/or "piss" out CO2, nitrogen compounds and phosphates. Nitrogen eventually leaves the system as a gas, or is fixed by algae. Phosphates are either removed by skimming or fixed by algae. Algae removal is an important part of nutrient export.

The infauna then just seems like more bioload - anything they eat can/will be broken down by the bacteria.

Please note that I do not want to portray myself as a DSB loyalist or a Shimek devotee. I like to think that I am unbiased and base my opinions on "facts" and known, established phenomena in biology. I have read many of the posts for and against DSB, as well as many articles (albeit, all of the "unbiased" articles I have read were sited by Shimek), but it really seems that all the mechanics for how and why a DSB should work are all there. However, I could be missing something really obvious that causes the entire mechanism to break down and stop working. I would welcome some good discussion on this point, since I currently have a DSB in a smaller tank, and I am planning on installing one in my next large tank sometime in the future.

Kindest regards,
Q

I don't think you are a loyalist, and I am happy to be having this discussion without the 'heat'
The denitirfication abilities of sand aren't in question (I think), its what do the infauna do.
And it isn't that the DSB stops working, its that it simply cant export everything forever. Ask Ron for some data supporting the idea that it can - maybe he will actually give it to you!
The RC search engine is down, but later I will find that thread for you.
This is a good discussion. Lets keep it going.

 

[Anonymous]

One thing I have learned in this hobby is that there are many different ways to successfully keep a reef tank. There is no one way to do it.

You betcha!

What works for one person may not work for another (or vise versa) due to the suttle differences between tank and husbandry practices.
Seeing what works for different individuals is always very interesting and IMO is health dialog, but stating what works and what doesn't makes no sense. Understanding this hobby has changed so much in the last few years, I am sure we are still in for a lot more learning.
My 2c

We are still learning, and what I find interesting is that until recently no one questioned DSB methodology. When it did finally get looked at, no support for it could be found. The science says the sand will fill up - DSB people say it won't but don't/won't/can't show any actual evidence of it. If DSB's don't work they say they do, it seems to make much sense to me to say so.

It will continue to change, and I think it is critical to the hobby that we keep looking at dogma with a critical eye.

 

[Fastmarc]

It will continue to change, and I think it is critical to the hobby that we keep looking at dogma with a critical eye.

Yup.

 

[Anonymous]

Righty!


8) 8) 8) 8)

i dig it.

can't say i will be yanking mine until i have a reason too.


as for the infauna in a sand beds..... they do what everything i put in my tank does... they entertain me.
i like having a diverse population of life and assume it makes for more interesting scenery.
i have seen a lot of BB tanks lately and while they are very clean looking, they lack something i see in sand bed tanks.

anyway.. like i said, the tanks looks sweet.. as always

 

[Anonymous]

Mighty Quinn,

Here is a decent thread, not the one I was talking about, but a good one.

http://reefs.org/phpBB2/viewtopic.php?t=43370&start=0

 

[Anonymous]

Righty!


8) 8) 8) 8)

i dig it.

can't say i will be yanking mine until i have a reason too.

I had reason. 2 RTN events caused by SB disturbances. Yech.
[/quote]

as for the infauna in a sand beds..... they do what everything i put in my tank does... they entertain me.
i like having a diverse population of life and assume it makes for more interesting scenery.
i have seen a lot of BB tanks lately and while they are very clean looking, they lack something i see in sand bed tanks.[/quote]

I thought the same thing, but now I dont think I miss it too much. It actually looks more like a slice of a real reef to me - sand is pretty far form the corals in the oceans.
I may put a FSB in there, but we will see how the coraline grows.

I think the only reason for sand or infauna is because you like em, not because someone said they will keep your tank clean.

anyway.. like i said, the tanks looks sweet.. as always

:mrgreen:

 

[RobertoVespucci]

I feel like this is my first Thanksgiving at the 'big table' and everyone is discussing politics and I'm not following.

How does the dsb fill up? Or by that do you mean that you eventually input nutrients faster than the bacteria can eliminate them? Does all the water space in between sand grains get displaced by insoluble waste? The dsb failure thing is new to me.

 

[Mighty Quinn]

Mighty Quinn,

Here is a decent thread, not the one I was talking about, but a good one.

http://reefs.org/phpBB2/viewtopic.php?t=43370&start=0

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.

One thing that I don't understand. Many people state that DSB's are "nutrient sinks" or "phosphate sponges". I just don't get this. I don't understand why the phosphate doesn't go into the water column and get pulled out by algae. Why would it stay in the DSB? Help me out on this one.

I'm looking forward to figuring this thing out. Thanks for your patience.

Kindest regards,
Q

 

[Oceans Ferevh]

I have a picture of your tank on my desktop. I'm not a fan of how barebottoms look...but you know what your doing and I'm sure it'll look just as fantastic soon

 

[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.


I would say I'm convinced that I would prefer shallower sand. Is there a minimum sand depth needed for sand dwellers to do their thing? You know, pistol shrimp, sifting gobies, and whatever else I forgot this early in the morning?

 

[Anonymous]

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.

One thing that I don't understand. Many people state that DSB's are "nutrient sinks" or "phosphate sponges". I just don't get this. I don't understand why the phosphate doesn't go into the water column and get pulled out by algae. Why would it stay in the DSB? Help me out on this one.

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. 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!

I'm looking forward to figuring this thing out. Thanks for your patience.

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

 

[Anonymous]

I have a picture of your tank on my desktop. I'm not a fan of how barebottoms look...but you know what your doing and I'm sure it'll look just as fantastic soon

Aww, shucks!

 

[Anonymous]

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!

I would say I'm convinced that I would prefer shallower sand. Is there a minimum sand depth needed for sand dwellers to do their thing? You know, pistol shrimp, sifting gobies, and whatever else I forgot this early in the morning?

I would say 1/2 inch to an inch. But it really depends on the specific animal.

 

[Unarce]

OK, just for good measure, I thought I'd add my sand bed templates :

If you were to set up a reef tank with high current, than there would be a lot of bare areas if you had a SB less than an inch high. 2-3 inches is the absolute best way to go. It would be incorrect to claim that a sand bed provides 'more capacity to nitrify and denitrify' simply because it's deeper.

"As much as 70 to 90 percent of the overall denitrification was located in the uppermost centimeter. The remainder was found at 1-3 cm depth"

-T.K. Anderson 1984 "Diurnal Variations of Nitrogen Cycling in Coastal, Marine Sediments."

"anaerobic habitat can be as small as 1mm, that aerobic and anaerobic bacteria essentially coexist, and that as little as 0.08mm distance is sufficient for nitrification and denitrification to take place simultaneously."

-Ecology and Evolution in Anoxic Worlds. Oxford University Press, Fenchel, T. and B.J. Finlay. 1995.

The misunderstanding is that areas with low levels of oxygen are a must for denitrification. Since we now know that aerobic and anaerobic bacteria exist together in the upper portion of the SB, than the heavy oxygen levels of our tanks would not be a factor. It's unlikely that denitrification will occur in the deep areas of a DSB, especially if nitrates never reach it in the first place.

I'd also like to point out that a deeper sand bed doesn't necesarily equate to more biodiversity of life. A shallow sand bed of numerous grain-size will create a number of different environments housing more life than a DSB.

Another misconception is that the smaller the grain-size, the more surface area there is for bacteria. This would certainly hold true if we assumed that every grain was a perfectly round sphere. But, take into account the rough edges, crevices, and porosity of larger grains, then it becomes quite comparable.

Like many, I like the pleasing aesthetics of fine sand (which makes up most of my shallow sand bed). But, having multi-grains with the larger pieces turning into miniature live rock themselves has certainly added to the sand bed's functionality as well as its appearance.

I currently have a 1/2" sand bed in my SPS tank.