Val Shebeko
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So the water seeps through 12 inches of sand using gravity flow and then goes back into the tank ?
Controllable deep sand beds - a discussion thread
- Thread starter Sallstrom
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So the water seeps through 12 inches of sand using gravity flow and then goes back into the tank ?
OP
OP
Sallstrom
2500 Club Member
Here's an idea I want to try more. I've tried it once but put a layer of Siporax in the bottom and it turned out Siporax release a lot of silicate in anaerobic conditions. So I had to stop it and havn't had the time or place to try it again.
The idea is a box inside the sump, with inlet at the bottom. Water is pumped out from the top water layer. This way it's easier to know how much water goes through the sand bed, and it's easy to put pH and redox probes to see the numbers after the sand bed. You could also feed the sand bed with carbon source and regulate the dosage and flow with the pH and redox(maybe). Anyway, not easy to explain in text so I draw this in power point
I call it David's reverse deep sand bed, or just DRDSB
Okey, I will explain the idea in this post a little bit more. I wanted somewere to grow bacteria with the help from added DOC. We use ethanol a lot at work, just adding right into the tanks, but I wanted to try to keep the carbon source and bacteria away from the tank, maybe even run the utcoming water directly to a skimmer. And also wanted to get an area which were anaerobic and possible to control by meassuring redox of the outcoming water.
So therefore the flow would be pretty slow(I know about Paul B's undergravel filter but I don't know the flow rate). But could be increased if redox decreased. So in a way runned like a sulphur filter, but using carbon source instead.
Another thing why I would put the dosing pump(or whatever pump that will make the flow through the filter/sand bed) after the sand bed is to be able to know the flow. Also put a pump on the inlet and do a overflow in the box, and you will have a pump thats struggling against the sandbed compared to if a pump takes the water from the top layer.
If a DSB and a plenum should have a certain depth, that I leave to the people who wants to follow a "recipe"
I like to try things out for myself 
Here's some pictures of the "demo" I did. Don't know why I did such a large on, next one will be smaller
Like I wrote in the first post about this "box", we saw on our Triton ICP tests the the Silica(Si) started to increase a lot after the filter was started. So putting Siporax in a anaerobic filter(we experienced it with other silica based filter as well) was not a good idea. The filter was taken out and the refugium where it stood was needed for corals. So I haven't tried it again. I'm thinking of doing a really small box, maybe a litre of so, just to try control it with redox and dosing pumps.
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Tajaba
Community Member
Yes, but not all at once. Some will overflow the aDSB and is sent back up to the main display as well since I didn't want to go through the process of controlling both the return pump and recirculating pump with the ORP sensor.
Dr. Dendrostein
Marine fish monthly
And yes you will control orp, thru dosing pump if: 1. pump can move enough h2o, 2. detritus doesn't clog flow. 3. Very little oxygen present . When threshold hold of orp reached, 0-150-(?), if some oxygen present at plenum area, when dosing pump activates, orp will go close to zero, from 150-. Hopefully low in the positive reading . If my brain recalls. Correct me someone, won't hurt my feelings, getting old.Okey, I will explain the idea in this post a little bit more. I wanted somewere to grow bacteria with the help from added DOC. We use ethanol a lot at work, just adding right into the tanks, but I wanted to try to keep the carbon source and bacteria away from the tank, maybe even run the utcoming water directly to a skimmer. And also wanted to get an area which were anaerobic and possible to control by meassuring redox of the outcoming water.
So therefore the flow would be pretty slow(I know about Paul B's undergravel filter but I don't know the flow rate). But could be increased if redox decreased. So in a way runned like a sulphur filter, but using carbon source instead.
Another thing why I would put the dosing pump(or whatever pump that will make the flow through the filter/sand bed) after the sand bed is to be able to know the flow. Also put a pump on the inlet and do a overflow in the box, and you will have a pump thats struggling against the sandbed compared to if a pump takes the water from the top layer.
If a DSB and a plenum should have a certain depth, that I leave to the people who wants to follow a "recipe"
Here's some pictures of the "demo" I did. Don't know why I did such a large on, next one will be smaller
Like I wrote in the first post about this "box", we saw on our Triton ICP tests the the Silica(Si) started to increase a lot after the filter was started. So putting Siporax in a anaerobic filter(we experienced it with other silica based filter as well) was not a good idea. The filter was taken out and the refugium where it stood was needed for corals. So I haven't tried it again. I'm thinking of doing a really small box, maybe a litre of so, just to try control it with redox and dosing pumps.
jjflounder1
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You would have to have some minimal amount of flow ... Even if it's only measured in gallons a month ... Or you don't get an exchange of the good and the bad ...
In my opinion zero flow is how a dsb can crash ... Even if it is doing it's job .... It will run out of things aka new water to process ....
There in lies the KEY to a dsb ... Too little flow it dies too much flow it's just a sand filter ( like your swimming pool)
Dr. Dendrostein
Marine fish monthly
I smell hydrogen sulfide
OP
OP
Sallstrom
2500 Club Member
Yes, I my case I didn't have a dosing pump large enough to keep the right flow. So when I tested dosing carbon source the redox decreased really fast and pretty soon the top layer of water was all milky white and didn't take long until the bacteria clogged The dosing pump inlet. So it wasn't a success
That's why I want to try a smaller one and see if it's possible and if it feels like something worth implementing in a sump. Not sure it is yet
About redox @Lasse is the person to ask. I think we aimed for -180 but that might have been a sulphur reactor..
Tajaba
Community Member
Funny you mention it, I had a canister full of live rock that got clogged after about 4 years of reefing (I basically forgot it existed). I suspect it had absolutely no flow into and out of it in the end of its life because when I opened it up, boy the smell stank my kitchen for days.
So we actually might be on to something here.
A description of my system
When I planned the aquarium I add a special compartment in the back of the DT with overflow from the DT
In this apartment I start to build construction the leave a small amount of water below the sand bed. Plenum. I add some tubes too
I did a solution in order to be able to put down some pH and ORP probes
When I construct the sand bed - I started with siporax in the bottom. It was no good idea - because after a year and a half, my silicon levels was 20 ppm and I did want 0.1 ppm. Half a year ago - I dig up the whole bed (and it was as clean as I started it) - took away the Siporax and add some curse coral sand instead.
But it looks like this in the start
One of the tubes is my inlet from the pump
Reversed lighting and reversed flow
Today I run a slow reversed flow through the sand bed. I do add som DOC sometimes and when I do that - the flow rate is around 100 l/day - otherwise 29 - 60 litres a day. If I want to have aerob breakdown - I´m able to run around 400 l/h - if I want. Today I try to run around 0 mV (ORP) in the plenum - I have not yet found how I should configure my measurements in order to get as low variation as possible. I use a pump giving around 600 l/h as max an steady running. In my case it only run for 1 second in a 3 minutes period if ORP lower than 0.
I have to add both PO4 and NO3 on a daily schedule.
Sincerely Lasse
When I planned the aquarium I add a special compartment in the back of the DT with overflow from the DT
But it looks like this in the start
One of the tubes is my inlet from the pump
The top of the DSB is my bottom of my fuge
I have to add both PO4 and NO3 on a daily schedule.
Sincerely Lasse
Mortie31
Valuable Member
Do you think it would be possible to use something like the aqua medic denitrators and replace the bioballs with sand and coral rubble? A carbon source is added through a dosing pump and the probe could be linked to an external dosing pump would add a few litres of fresh tank water every hour, the redox can therefore be easily maintained at -200mv, the internal circulation pump would stop hydrogen sulphide pockets forming. So you end up with a semi fluidised sand bed with zero oxygen.
https://www.drsfostersmith.com/Media/PDF/19139-NitrateReductorManual.pdf
I’ve built something similar using an ALR2 reactor but have used siporax as the media, but now wondering if sand/ coral rubble might be better.
https://www.drsfostersmith.com/Media/PDF/19139-NitrateReductorManual.pdf
I’ve built something similar using an ALR2 reactor but have used siporax as the media, but now wondering if sand/ coral rubble might be better.
Dr. Dendrostein
Marine fish monthly
Ok, my head stop hurting,
@Lasse, this is going to hurt my brain. Do I understand you, are you trying to get lower orp readings, than 0 orp? Sorry if I'm a little slow. Getting old. Talk to me like a 4 year old. Many thanks
A description of my system
When I planned the aquarium I add a special compartment in the back of the DT with overflow from the DT
In this apartment I start to build construction the leave a small amount of water below the sand bed. Plenum. I add some tubes too
I did a solution in order to be able to put down some pH and ORP probes
When I construct the sand bed - I started with siporax in the bottom. It was no good idea - because after a year and a half, my silicon levels was 20 ppm and I did want 0.1 ppm. Half a year ago - I dig up the whole bed (and it was as clean as I started it) - took away the Siporax and add some curse coral sand instead.
But it looks like this in the start
One of the tubes is my inlet from the pump
The top of the DSB is my bottom of my fuge
Reversed lighting and reversed flow
Today I run a slow reversed flow through the sand bed. I do add som DOC sometimes and when I do that - the flow rate is around 100 l/day - otherwise 29 - 60 litres a day. If I want to have aerob breakdown - I´m able to run around 400 l/h - if I want. Today I try to run around 0 mV (ORP) in the plenum - I have not yet found how I should configure my measurements in order to get as low variation as possible. I use a pump giving around 600 l/h as max an steady running. In my case it only run for 1 second in a 3 minutes period if ORP lower than 0.
I have to add both PO4 and NO3 on a daily schedule.
Sincerely Lasse
@Lasse, this is going to hurt my brain. Do I understand you, are you trying to get lower orp readings, than 0 orp? Sorry if I'm a little slow. Getting old. Talk to me like a 4 year old. Many thanks
Yes below the plenum I want low ORP readings. Normally you have a good denitrification between -70 and -200 mV but there is no direct denitrification value - it will differ.
By the way - as long as you have NO3 in the water or the bed - there is a low risk to get hydrogen sulphide.
Sincerely Lasse
By the way - as long as you have NO3 in the water or the bed - there is a low risk to get hydrogen sulphide.
Sincerely Lasse
Dr. Dendrostein
Marine fish monthly
@Lasse, I think you need deeper sand bed. Trail and error. Hard for me to measure orp in different layers. Maybe you figure that
Scrubber_steve
2500 Club Member
Bob Goemans correctly uses the term 'anoxic' to describe a zone that contains an oxygen level of approximately 0.5 to 2.0 mg/litre and >>> directly due to this<<< destructive denitrification occurs ( NO3 to nitrogen gas).
The often & incorrectly term used 'anaerobic' represents a zone that contains less oxygen than the anoxic condition, and >>> directly due to this <<< the ammonification form of denitrification occurs (NO3 is converted back to ammonia). Hydrogen sulphide will also form in an anaerobic zone, so creating such an environment must be avoided.
Substrate grain size & depth, along with flow rate through, are key considerations for success in this type of nutrient processing method especially if a thick substrate is being utilised. Removal of organic particulate matter from the water entering the substrate would be necessary. But over time channelling can occur leaving dead spots - anaerobic zones. If fine sediments eventually have high organic matter loading they tend to go anoxic/anaerobic at very shallow depths - between a few centimetres to a few millimetres.
This method is not set & forget. Organic matter build up in the substrate, compaction of the substrate & channelling of flow through the substrate can cause subtle changes that can lead to disaster over time.
Some interesting reading onthe subject I found a while back
The Plenum Method…… by Bob Goemans
http://www.saltcorner.com/Articles/Showarticle.php?articleID=117
Sandbeds - Part I by Bob Goemans and Sam Gamble
http://www.saltcorner.com/Articles/Showarticle.php?articleID=22
Sandbeds - Part II by Bob Goemans and Sam Gamble
http://www.saltcorner.com/Articles/Showarticle.php?articleID=23
Jaubert's Method, The 'Monaco System,' Defined And Refined
By Julian Sprung
http://www.advancedaquarist.com/2002/9/aafeature
ORP meter reading in deep sand bed
As mentioned above, this order of electron acceptors used to oxidize organic material is oxygen (O2), then nitrate (NO3-), then manganese (Mn++++), then iron (Fe++), then sulfate (SO4--). Researchers can plot the concentrations of these chemicals as a function of depth, and can also associate an ORP with each transition, although some overlap of the chemistries takes place in each zone. The oxygen zone has an ORP of 0 to 600 mV, the nitrate zone is -150 to 550 mV, the manganese zone is -50 to 400 mV, the iron zone is -700 to -150 mV and the sulfate reduction zone is -850 to 0 mV. Consequently, if hydrogen sulfide is being formed from sulfate, the ORP is likely below 0 mv in that region.
The often & incorrectly term used 'anaerobic' represents a zone that contains less oxygen than the anoxic condition, and >>> directly due to this <<< the ammonification form of denitrification occurs (NO3 is converted back to ammonia). Hydrogen sulphide will also form in an anaerobic zone, so creating such an environment must be avoided.
Substrate grain size & depth, along with flow rate through, are key considerations for success in this type of nutrient processing method especially if a thick substrate is being utilised. Removal of organic particulate matter from the water entering the substrate would be necessary. But over time channelling can occur leaving dead spots - anaerobic zones. If fine sediments eventually have high organic matter loading they tend to go anoxic/anaerobic at very shallow depths - between a few centimetres to a few millimetres.
This method is not set & forget. Organic matter build up in the substrate, compaction of the substrate & channelling of flow through the substrate can cause subtle changes that can lead to disaster over time.
Some interesting reading onthe subject I found a while back
The Plenum Method…… by Bob Goemans
http://www.saltcorner.com/Articles/Showarticle.php?articleID=117
Sandbeds - Part I by Bob Goemans and Sam Gamble
http://www.saltcorner.com/Articles/Showarticle.php?articleID=22
Sandbeds - Part II by Bob Goemans and Sam Gamble
http://www.saltcorner.com/Articles/Showarticle.php?articleID=23
Jaubert's Method, The 'Monaco System,' Defined And Refined
By Julian Sprung
http://www.advancedaquarist.com/2002/9/aafeature
ORP meter reading in deep sand bed
As mentioned above, this order of electron acceptors used to oxidize organic material is oxygen (O2), then nitrate (NO3-), then manganese (Mn++++), then iron (Fe++), then sulfate (SO4--). Researchers can plot the concentrations of these chemicals as a function of depth, and can also associate an ORP with each transition, although some overlap of the chemistries takes place in each zone. The oxygen zone has an ORP of 0 to 600 mV, the nitrate zone is -150 to 550 mV, the manganese zone is -50 to 400 mV, the iron zone is -700 to -150 mV and the sulfate reduction zone is -850 to 0 mV. Consequently, if hydrogen sulfide is being formed from sulfate, the ORP is likely below 0 mv in that region.
Dr. Dendrostein
Marine fish monthly
You need to somehow circulate water very close from exit of dsb back to plenum. To get a good mix of water in dsb. So orp more accurate reading. I think?
Dr. Dendrostein
Marine fish monthly
Those names bring back memories, when just getting into reef keeping. Im old.
Dr. Dendrostein
Marine fish monthly
Mortie31
Valuable Member
Would an internal circulation pump, like in the system I posted above achieve this? The internal water is circulated at 400L/hr in the pressurised cylinder, tank water is fed into the system very slowly. Would sand/ coral pieces work in this situation? I know it works with siporax, the water exiting the system is NO3 = 0. The ORP readings I currently run it at are about -150mv.
Dr. Dendrostein
Marine fish monthly
I think so, @Lasse, need to avoid drawing water outside of dsb, when circulating back to plenum. I think if I was designing your tank, maybe you have this already done to it. I would have isolated dsb add recirculation, and one more orp at the exit (which is possible still, for the sensor) of dsb. Isolated so when orp is -150-180. Move some of that water to main tank thru sump?
Dr. Dendrostein
Marine fish monthly
Not too shabby for a dumb, Latino/Jew. What I tell you @Lasse,,Apple doesn't fall to far from the tree. Heehee
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