Deep Sand Bed -- Anatomy & Terminology

Korrine said:
This is a great read. However, I'm now confused as ever. To DSB or not DSB :hmm2:

I am setting up a 75g FOWLR aggressive tank and was considering doing a 16"x18"x6"H sand bed in the sump to help with nitrates. Also having cheato on top. Sounds like I should just go with cheato, eh?
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You can just go with cheato and it should work fine. Having no sand on the bottom does make it easier to keep clean. There are benefits to having a DSB though. It's just important to keep in mind that the typical thinking behind DSB's is greatly flawed. You wouldn't allow a caged hamster, snake, bird, or any other pet, to deposit its own waste on the bottom of the cage until worms, insects, and their larvae set up shop and began feeding on it. This would cause your pet to become ill and possibly die. You MUST keep their cage clean. There is little difference when it comes to the delicate coral reef species we try to keep in our little glass cages. We must keep their environment clean. The presence of large numbers of detritivores, like bristle worms, in a DSB is a sign that there is a large amount of detritus (waste) in the sand. You wouldn't force a hamster to live under such conditions. Why force some of the most environmentally sensitive creatures on the planet to live under such horrid conditions? If you do go with a DSB, just keep it clean. Critters like bristle worms will not keep the sand clean for you, any more than maggots living on the bottom of a bird cage would keep it clean. A simple gravel vac ran through the sand during water changes will go a long way towards keeping the sand, and the system as a whole, clean. HTH.;)
 
elegance coral said:
You can just go with cheato and it should work fine. Having no sand on the bottom does make it easier to keep clean. There are benefits to having a DSB though. It's just important to keep in mind that the typical thinking behind DSB's is greatly flawed. You wouldn't allow a caged hamster, snake, bird, or any other pet, to deposit its own waste on the bottom of the cage until worms, insects, and their larvae set up shop and began feeding on it. This would cause your pet to become ill and possibly die. You MUST keep their cage clean. There is little difference when it comes to the delicate coral reef species we try to keep in our little glass cages. We must keep their environment clean. The presence of large numbers of detritivores, like bristle worms, in a DSB is a sign that there is a large amount of detritus (waste) in the sand. You wouldn't force a hamster to live under such conditions. Why force some of the most environmentally sensitive creatures on the planet to live under such horrid conditions? If you do go with a DSB, just keep it clean. Critters like bristle worms will not keep the sand clean for you, any more than maggots living on the bottom of a bird cage would keep it clean. A simple gravel vac ran through the sand during water changes will go a long way towards keeping the sand, and the system as a whole, clean. HTH.;)
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this is why I am an advocate of a remote dsb as in a refugium. I keep the sand bed to one inch or so in the display tank and keep that clean. However I do not vacuum it--I find using a turkey baster on it lightly, once a week does the trick.
The remote deep sand bed never gets touched and its been in operation for 4years that way.
 
Capn. How deep is your dsb? I was thinking 6" but that seems like it almost might be to much after reading 6" is max. May do 5"?
 
Korrine said:
Capn. How deep is your dsb? I was thinking 6" but that seems like it almost might be to much after reading 6" is max. May do 5"?
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my remote dsb is 6 inches. It has a layer of medium grade argonite on the bottom followed by a layer of sugar fine argonite and finally capped with a layer of medium argonite again.
 
I have a few questions... I have a 7 inch DSB in the last stage of my system. Water passes filter sock, skimmer, 55g with chato, and then to the DSB and LR. Should I be doing some kind of maintenance to this DSB?
 
saltn07 said:
I have 30 nassarius snail in it to help stir up the sand, is this good or bad?
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That is excellent--it also increases circulation and keeps the sand bed from clumping. Its critters like sand sifting stars, long leg crabs and other crabs that can do damage to a sand bed by eating the the inverts that are vital to the top layer of the bed
 
saltn07 said:
I have a few questions... I have a 7 inch DSB in the last stage of my system. Water passes filter sock, skimmer, 55g with chato, and then to the DSB and LR. Should I be doing some kind of maintenance to this DSB?
Click to expand...


You should have to do little maintenance with the way you have it setup.

You might want to consider spitting your drain and adding ball values to each t in the drain. This way you can control the flow to the refugium and deepsand bed which should be must less then the return flow to your tank.

Some reefers tend to go in reverse of yours --the one drain going to sand bed first, then refugium with macro and finally draining into the sump just before the water returns to the tank. This helps feed more inverts to the display tank for the fish and also allows the water to pool in the deep sand bed.
the other side of the drain can have more flow which goes to the filter sock and the skimmer. In these situations you really don't need a filter sock unless you are addressing micro bubbles in the display tank.
 
capn_hylinur said:
this is why I am an advocate of a remote dsb as in a refugium. I keep the sand bed to one inch or so in the display tank and keep that clean. However I do not vacuum it--I find using a turkey baster on it lightly, once a week does the trick.
The remote deep sand bed never gets touched and its been in operation for 4years that way.
Click to expand...

I too am an advocate of the remote DSB. It's much easier to keep the sand clean when ran remotely. The water can be filtered before reaching the sand, and there's no need to place LR on top of it, making it much more difficult to maintain. It's important to remember that it's all the same water though. You can't allow the fuge, or DSB area, to trap large quantities of decomposing waste without it effecting the water quality in the display.

We have to be leery of "rubber ducky science". I can float a rubber ducky in my tank. If my tank does well, is that evidence that the rubber ducky had anything to do with it? There are many ways to run a system. Just because someone adds a component to the system, and the system does well, it does not indicate that the component was beneficial. We have to study the science, the chemistry, the biology, behind the component before we can understand the effects it will have on a particular system. The effects of rot and decay on life forms like coral reef fish and stony corals is well understood. Unfortunately, there are authors in this hobby that would have us believe that rot and decay are somehow good for these animals. It's not. It's good for those critters that feed on rotting, decomposing matter. Just like bird poo on the bottom of a bird cage would be good for maggots, but not so good for the bird. A sand bed, no matter where it is in the system, that's loaded with enough rot and decay to support large numbers of critters like bristle worms, will not be good for critters like coral reef fish and stony corals.
 
Rodents and raptors aside,let's back up a step to understand why some nutrients are needed and conversely why a sand bed or alternative nitrogen removal actions are needed.

Living things consume nitrogen,phosphorous and carbon to build proteins and living tissue. Foods contain them. Excess is expelled via respiration , passing waste or in death via decay. It's recyled via aerobic and anaerobic bacteria activity in the water, soil or other surfaces as well as activity in anoxic areas. So some nutrients are needed but not too many. Reefs flourish in nature because they get nutrients that well up through the live rock but the nutrient levels constantly maintained in the upper reef regions is extremely low.

In a closed system the amounts carbon(C), nitrogen(N)and phosphorous(P) can easily reach excessive levels directly harmful to some life forms and/or harm them via excesseively high levels of bacterial activity the nutrients support. . In aqauriums it is critical to have a means to export the excess C,N and P which will vary based on how much you feed and how many fish you try to support. Skimming, granulated activated carbon ,mechanical filtration, etc are all ways to do it.

Sand beds , macro algae growth and live rock and other means of bio filtration are others.

When choosing a design for a refugium pick the method that makes sense in terms of nutrient removal in the context of your overall system design. For example, a system in a basement with unlimited space might rely on well lit macro algae refugia, while a more confined system might relay on phosphate or nitrate reactors with N and P removing media.Many rely on a mix of export measures.

Remote shallow sand beds ( and inch or so) are just as effective as deep ones at nitrification( ammonia to nitarite to nitrate) and denitrification ( nitrate to nitrogen gas) because most of the deeper sand does not receive C,N and P sufficient to support the heteroptrophic bacteria that perform denitrification. Diffusion simply is weak and will not move the nutrients down,suficientlty. Channeling benthic fauna will but maintaining them in low nutrient system is challenging long term . Advection may help move the nutrients down by increasing the flow in the lower regions of the sand bed. . When water hits an obstruction such as a live rock stack or a reef in nature , the lower pressure under the obstruction causes an upwelling and consequent downward flow of water. The amount of flow depends on the rate of flow hitting the obstruction and the height of the obstruction.

Macro algae over sand makes a mess in my experience. . The aglae exudate settles out on and into the bed depositing more CNP than the sand can process.

Among other things, I use a remote deep sand bed covered with relatively tall live rock. I also use bare bottom chaeto refugia and some live rock in dark ( cryptic) areas.If I had to choose one I'd choose a bare bottom chaeto refugium with as much surface area and light on opposite photo period that I could reasonably provide.
 
tmz said:
Rodents and raptors aside,let's back up a step to understand why some nutrients are needed and conversely why a sand bed or alternative nitrogen removal actions are needed.

Living things consume nitrogen,phosphorous and carbon to build proteins and living tissue. Foods contain them. Excess is expelled via respiration , passing waste or in death via decay. It's recyled via aerobic and anaerobic bacteria activity in the water, soil or other surfaces as well as activity in anoxic areas. So some nutrients are needed but not too many. Reefs flourish in nature because they get nutrients that well up through the live rock but the nutrient levels constantly maintained in the upper reef regions is extremely low.

In a closed system the amounts carbon(C), nitrogen(N)and phosphorous(P) can easily reach excessive levels directly harmful to some life forms and/or harm them via excesseively high levels of bacterial activity the nutrients support. . In aqauriums it is critical to have a means to export the excess C,N and P which will vary based on how much you feed and how many fish you try to support. Skimming, granulated activated carbon ,mechanical filtration, etc are all ways to do it.

Sand beds , macro algae growth and live rock and other means of bio filtration are others.

When choosing a design for a refugium pick the method that makes sense in terms of nutrient removal in the context of your overall system design. For example, a system in a basement with unlimited space might rely on well lit macro algae refugia, while a more confined system might relay on phosphate or nitrate reactors with N and P removing media.Many rely on a mix of export measures.

Remote shallow sand beds ( and inch or so) are just as effective as deep ones at nitrification( ammonia to nitarite to nitrate) and denitrification ( nitrate to nitrogen gas) because most of the deeper sand does not receive C,N and P sufficient to support the heteroptrophic bacteria that perform denitrification. Diffusion simply is weak and will not move the nutrients down,suficientlty. Channeling benthic fauna will but maintaining them in low nutrient system is challenging long term . Advection may help move the nutrients down by increasing the flow in the lower regions of the sand bed. . When water hits an obstruction such as a live rock stack or a reef in nature , the lower pressure under the obstruction causes an upwelling and consequent downward flow of water. The amount of flow depends on the rate of flow hitting the obstruction and the height of the obstruction.

Macro algae over sand makes a mess in my experience. . The aglae exudate settles out on and into the bed depositing more CNP than the sand can process.

Among other things, I use a remote deep sand bed covered with relatively tall live rock. I also use bare bottom chaeto refugia and some live rock in dark ( cryptic) areas.If I had to choose one I'd choose a bare bottom chaeto refugium with as much surface area and light on opposite photo period that I could reasonably provide.
Click to expand...

I am glad to hear that you run your remote deep sand bed with live rock. I have found a lot of reefers criticize that as they feel it impedes the functioning of the deep sand bed by covering it. All I have to go on, is that my dsb appears to be working as I have zero nitrates.
I need that live rock in the system to handle the 16 fish bioload that I have. If I were to put it in the display tank my tangs would get fin cramps:hmm1:

I, like you run a separate refugium for cheato. I does have a 3 inch sand bed in the bottom but it has been there for 4 years and I am not about to disturb it now.

Tom, one question---the process of converting nitrites to nitrates--isn't that also denitrification?
 
elegance coral said:
I too am an advocate of the remote DSB. It's much easier to keep the sand clean when ran remotely. The water can be filtered before reaching the sand, and there's no need to place LR on top of it, making it much more difficult to maintain. It's important to remember that it's all the same water though. You can't allow the fuge, or DSB area, to trap large quantities of decomposing waste without it effecting the water quality in the display.

We have to be leery of "rubber ducky science". I can float a rubber ducky in my tank. If my tank does well, is that evidence that the rubber ducky had anything to do with it? There are many ways to run a system. Just because someone adds a component to the system, and the system does well, it does not indicate that the component was beneficial. We have to study the science, the chemistry, the biology, behind the component before we can understand the effects it will have on a particular system. The effects of rot and decay on life forms like coral reef fish and stony corals is well understood. Unfortunately, there are authors in this hobby that would have us believe that rot and decay are somehow good for these animals. It's not. It's good for those critters that feed on rotting, decomposing matter. Just like bird poo on the bottom of a bird cage would be good for maggots, but not so good for the bird. A sand bed, no matter where it is in the system, that's loaded with enough rot and decay to support large numbers of critters like bristle worms, will not be good for critters like coral reef fish and stony corals.
Click to expand...


Elegance---you seem to have a hate on for the poor bristle worms:lmao:

I agree with you about the rotting matter but a dsb should not be managed like that in the first place. Things like Tom mentioned---keeping cheato out of it for eg---can maintain the surface of it.
I don't really see the problem with any decaying matter in the lower levels of the sand bed being any threat to the display tank however
 
capn_hylinur said:
Elegance---you seem to have a hate on for the poor bristle worms:lmao:
Click to expand...

:lmao: You gotta admit, they ain't the prettiest critters in the world.;)

I agree with you about the rotting matter but a dsb should not be managed like that in the first place. Things like Tom mentioned---keeping cheato out of it for eg---can maintain the surface of it.
Click to expand...

That's my whole point. To keep a sand bed from becoming a source of dissolved nutrients, it must be kept clean. Small pieces of cheato, uneaten fish food, critter poo, dead organisms like bristle worms, pods, and microbes, will all decompose in a sand bed and release the nutrients they hold into the environment. The only way to keep this process from taking place is to remove this organic matter before it decomposes in the sand. In other words, keep the sand clean.

I don't really see the problem with any decaying matter in the lower levels of the sand bed being any threat to the display tank however
Click to expand...

There is no invisible force field on top of a DSB that keeps substances like nitrate and phosphate from escaping. If water enters a sand bed, there will be an equal amount of water exiting the sand. If this water passes over, through, or around organic matter as it decomposes, it will pick up nutrients like nitrate and phosphate and carry them out of the sand. These nutrients will then be dispersed throughout the system. Even to the display tank. It's one body of water. It's next to impossible to maintain high nutrient levels within the fuge and low nutrients within the display. Naturally.......there will be a conversion of nitrate to nitrogen gas deep within the sand. This is not a 100% efficient process, so there will be both nitrate and nitrogen gas escaping from deep within the sand. If there were no rotting organic matter deep within the sand, this wouldn't be an issue. Then you have all the organic matter that rots above the anaerobic area. The nutrients released here, like nitrate, are just as likely to be transported back into the display as it is to be transported to the anaerobic area of the sand. Then we have phosphates that are released through decomposition. In a mature and well established system, there will be no reduction of phosphate in a sand bed. Phosphate effects stony coral growth, health, and fuels problem algae. If there is enough rotting organic matter to support large numbers of detritivores in the sand, there will be a constant release of phosphates into the system from the sand.
One of the easiest ways to manage nutrients like nitrate and phosphate is to remove them. No matter where they are in the system. Tiny particles of uneaten fish food, fish poo, and dead organisms (detritus) are harmless as long as they remain solid particles. It's not until they decompose, that they release the nutrients they hold. If we remove them from the system while they are still solid particles, they can not release their nutrients into the system. In other words, keep the sand relatively free of organic matter, and you won't have a nitrate and phosphate factory on the bottom of the tank.
 
elegance coral said:
:lmao: You gotta admit, they ain't the prettiest critters in the world.;)



That's my whole point. To keep a sand bed from becoming a source of dissolved nutrients, it must be kept clean. Small pieces of cheato, uneaten fish food, critter poo, dead organisms like bristle worms, pods, and microbes, will all decompose in a sand bed and release the nutrients they hold into the environment. The only way to keep this process from taking place is to remove this organic matter before it decomposes in the sand. In other words, keep the sand clean.



There is no invisible force field on top of a DSB that keeps substances like nitrate and phosphate from escaping. If water enters a sand bed, there will be an equal amount of water exiting the sand. If this water passes over, through, or around organic matter as it decomposes, it will pick up nutrients like nitrate and phosphate and carry them out of the sand. These nutrients will then be dispersed throughout the system. Even to the display tank. It's one body of water. It's next to impossible to maintain high nutrient levels within the fuge and low nutrients within the display. Naturally.......there will be a conversion of nitrate to nitrogen gas deep within the sand. This is not a 100% efficient process, so there will be both nitrate and nitrogen gas escaping from deep within the sand. If there were no rotting organic matter deep within the sand, this wouldn't be an issue. Then you have all the organic matter that rots above the anaerobic area. The nutrients released here, like nitrate, are just as likely to be transported back into the display as it is to be transported to the anaerobic area of the sand. Then we have phosphates that are released through decomposition. In a mature and well established system, there will be no reduction of phosphate in a sand bed. Phosphate effects stony coral growth, health, and fuels problem algae. If there is enough rotting organic matter to support large numbers of detritivores in the sand, there will be a constant release of phosphates into the system from the sand.
One of the easiest ways to manage nutrients like nitrate and phosphate is to remove them. No matter where they are in the system. Tiny particles of uneaten fish food, fish poo, and dead organisms (detritus) are harmless as long as they remain solid particles. It's not until they decompose, that they release the nutrients they hold. If we remove them from the system while they are still solid particles, they can not release their nutrients into the system. In other words, keep the sand relatively free of organic matter, and you won't have a nitrate and phosphate factory on the bottom of the tank.
Click to expand...

Thanks for the detailed answer Elegance.

'the easiest way to manage nutrients is to removed them'

this statement makes one revamp their ideas about a deep sand bed and its effeciency.
We can agree that chaeto macro algae removes both phosphate and nitrates from the system (providing one harvests it the proper way and stimulates its growth)
I am leaning towards the idea of keeping the one fuge for live rock only(something I have to do to keep room in the tank) and one for cheato.
Also in sumps that I maintain--doing away with the deep sand bed sections and running cheato and or live rock.
 
capn_hylinur said:
I am glad to hear that you run your remote deep sand bed with live rock. I have found a lot of reefers criticize that as they feel it impedes the functioning of the deep sand bed by covering it. All I have to go on, is that my dsb appears to be working as I have zero nitrates.
I need that live rock in the system to handle the 16 fish bioload that I have. If I were to put it in the display tank my tangs would get fin cramps:hmm1:

I, like you run a separate refugium for cheato. I does have a 3 inch sand bed in the bottom but it has been there for 4 years and I am not about to disturb it now.

Tom, one question---the process of converting nitrites to nitrates--isn't that also denitrification?
Click to expand...

No, nitrication includes the oxidation to nitrite. Nitrogen isn't really removed(,denitrification) until it is converted to nitrogen gas.
 
I am setting up a new system to include a 125 display a 110 sump (tub) with a 40 long frag tank. As I primarily will use unly the top of the frag tank, could I put the DSB in the frag tank or should I put it in the sump
 
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