remote DSB?
- Thread starter yeame
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ataylo13
habitual line stepper
Cody Ray
New member
This exact process has been done, it is featured in the 2006 issue of Marine fish & reef USA. Water is both pumped in from the top and bottom of the sandbed, it is called an upside-down sandbed. Water that is pumped in from the bottom travels up through the sandbed to the surface. It prevents the sandbed from becoming a nutrient sink. The author of the article demonstrated this by injecting red food dye in a regular DSB and an Upside-down sandbed. Dye that was injected into the DSB took days to resurface from the sandbed, some of it never exited. The dye injected into the UDS would resurface within an hour or less because of the flow. Although the amount of denitrifying bacteria may be reduced by the flow the remaining bacteria recieve a constant flow of water.
daytonians
New member
Basically your talking about a fluidized sand bed. The sand is kept partially suspended by the water moving up through it. They can work very well, but they have a big down side. It the water stops flowing for any reason, power goes out, pump breaks, etc., the bed colapses on itself suffocating the bacteria in it, and turning to muck in less than an hour.
BeanAnimal
Premium Member
So lets get this straight, you asked a question, were given an answer, but already knew what you wanted to hear?
A DSB and an "UPSIDE DOWN" sandbed are two totaly different things. If you do just a little resarch you will find out that pumping water into the bottom of a DSB will result in it NOT BEING A DSB!
So if you want a remote DSB, then you need to have water move over the sand and allow the bottom layers of sand to become anerobic. If you DONT WANT A DSB then feel free to pump water into the bottom of the bed.
You may also want to read the DSB IN A BUCKET thread. You will find out that the using the bucket is likely better than using the remote 40 gallon.
Bean
A DSB and an "UPSIDE DOWN" sandbed are two totaly different things. If you do just a little resarch you will find out that pumping water into the bottom of a DSB will result in it NOT BEING A DSB!
So if you want a remote DSB, then you need to have water move over the sand and allow the bottom layers of sand to become anerobic. If you DONT WANT A DSB then feel free to pump water into the bottom of the bed.
You may also want to read the DSB IN A BUCKET thread. You will find out that the using the bucket is likely better than using the remote 40 gallon.
Bean
Cody Ray
New member
I have already read that thread.
Unfortunatly I misquoted how the upside-down sandbed works. It uses a plenum and water is still pumped into it however it exits the other side upward onto the top of the bed. It doubles the amount of surface area for the bed. It still has flow through the sand but not as much as I said.
sorry for the small image
Unfortunatly I misquoted how the upside-down sandbed works. It uses a plenum and water is still pumped into it however it exits the other side upward onto the top of the bed. It doubles the amount of surface area for the bed. It still has flow through the sand but not as much as I said.
sorry for the small image
daytonians
New member
Personally, I would be afraid of it building up toxins and releasing them just like under gravel filters are known to do, but that is just me.
Cody Ray
New member
By toxins I assume you are refering to nitrate and phosphate. Phosphate is the only one that will bind to sand and once it is bound it won't unbind under normal circumstances (I believe a large downward swing in salinity will cause this). Eventually the sand will no longer be able to bind phosphate and people will experience an algae bloom (system crash). A phosphate reactor could be used to help with this.
Nitrate does not build up in the sand. If I were to guess why people with DSB had crashes I would say that the sand was no longer able to bind phosphate, phosphate built up and caused both algae growth and livestock to die, the dying livestock created a spike in nitrate and when the water was tested high nitrate levels were found and the crash was blamed on nitrate.
BeanAnimal
Premium Member
Chin...
I think that the question is going to come down to a high level conversation about the differences between a DSB, a PLENUM and a pseudo DSB that flows oxygenated water throught it.
I am not sure if the discussion will answer the OPs question, as each does something a little different and "best" or "better" can be very subjective.
For a remote DSB likely the bucket aproach will be the easiest and provide suitable results with little trouble and/or maintenance. The shelter from light will reduce a lot of the problems and negate the need for the range of fauna and larger lifeforms that would be needed in a lighted DSB or one that is NOT REMOTE and gets a LOT more detritus settling in it.
The question of critters stirring the "upside down bed" would be something for another topic. I guess "best" would also have to defined with regards to goals before we could compare any type of substrate system and clasify one as better than the other.
Bean
I think that the question is going to come down to a high level conversation about the differences between a DSB, a PLENUM and a pseudo DSB that flows oxygenated water throught it.
I am not sure if the discussion will answer the OPs question, as each does something a little different and "best" or "better" can be very subjective.
For a remote DSB likely the bucket aproach will be the easiest and provide suitable results with little trouble and/or maintenance. The shelter from light will reduce a lot of the problems and negate the need for the range of fauna and larger lifeforms that would be needed in a lighted DSB or one that is NOT REMOTE and gets a LOT more detritus settling in it.
The question of critters stirring the "upside down bed" would be something for another topic. I guess "best" would also have to defined with regards to goals before we could compare any type of substrate system and clasify one as better than the other.
Bean
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BeanAnimal
Premium Member
My intent was not to be rude. And I did mistake you for the original poster... if I can edit the post I will...
EDITED
EDITED
outy
New member
[chinchek787, You haven't given any proof of your response.]
no need for proof,,, its common knowledge that a remote dsb works and quite well at that.
the other idea is a problem waiting to happen if not it will still be a nitrate factory at best. why waist sand if you want to do that just play with a coil denitrator. The last i checked those are fine for FO but not quite effecient for a reef.
your talking about a set up that has to be tuned like a race car carburator with a tank failure if flow is to high or low and no real way to know unless you like to constantly test input and output water
no need for proof,,, its common knowledge that a remote dsb works and quite well at that.
the other idea is a problem waiting to happen if not it will still be a nitrate factory at best. why waist sand if you want to do that just play with a coil denitrator. The last i checked those are fine for FO but not quite effecient for a reef.
your talking about a set up that has to be tuned like a race car carburator with a tank failure if flow is to high or low and no real way to know unless you like to constantly test input and output water
Cody Ray
New member
I was not refering to proof that the remote DSB would work but that the other wouldn't work. After rereading the article I realized that it wasn't setup like I had stated. Water isn't being forced through the sand however it does have a tendency to travel upward through it because of the way it is setup. This still provides more flow than a regular DSB would but not so much that it would become fluidized. An anaerobic area develops in the middle of the sandbed instead of at the bottom. It is believed that the most effective form of denitrification occurs roughly an inch below the surface and that below this the bacteria do not recieve enough nitrate because the bacteria above it have used it. With an upside-down sandbed you only have an inch or two of denitrifying bacteria however it is located in the middle of the bed and the bottom of the bed becomes aerobic instead of almost dead space like a regular DSB.
daytonians
New member
ChinChek,
I was not referring to phosphate or nitrate. The low oxygen and no oxygen areas of a sand bed convert nitrates into a gas called N2. This is a highly toxic gas, but it is normally released in very small amounts which quickly bubble to the top of the water column and exit into the air. This is why it can be catastrophic to stir a deep sand bed. The stirring can release a large amount of the gas.
Many people believe that under-gravel filters allow this gas to build up and then be release in large quantites all at once. That is why they have fallen out of favor with reefers.
My fear with the upside down sand bed is that it would do the same, if there is not enough flow. Or, not allow for low to no oxygen zones if the flow is too fast. Without the anarobic (no oxygen) zones, the sand would be turning amonia into nitrate, with no way to convert the nitrate to N2.
I was not referring to phosphate or nitrate. The low oxygen and no oxygen areas of a sand bed convert nitrates into a gas called N2. This is a highly toxic gas, but it is normally released in very small amounts which quickly bubble to the top of the water column and exit into the air. This is why it can be catastrophic to stir a deep sand bed. The stirring can release a large amount of the gas.
Many people believe that under-gravel filters allow this gas to build up and then be release in large quantites all at once. That is why they have fallen out of favor with reefers.
My fear with the upside down sand bed is that it would do the same, if there is not enough flow. Or, not allow for low to no oxygen zones if the flow is too fast. Without the anarobic (no oxygen) zones, the sand would be turning amonia into nitrate, with no way to convert the nitrate to N2.
Cody Ray
New member
Unfortunatly you have mixed up 2 different gasess created by the sandbed. N2 (nitrogen) is completely harmless, it comprises 78% of the earths atmosphere. You may of been thinking of sulfur, which is also harmless http://en.wikipedia.org/wiki/Sulfur_water
The reason sulfur would accumilate in the UGF was that it was attempting to rise while the water was being pulled down. In an UDS (upside down sandbed) the water is moving upward in the same direction as the sulfur would want to. It could actually help prevent sulfur from building up in the sand. I havn't read any actually proof that sulfur itself is harmful at the amounts found in a sandbed.
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