TheFishMan65
New member
Bioload, what is the flow? I thoight he had high flow over the top. The trickle was just so he could "see" what was happening in the bed.
Flow Through DSB
- Thread starter bioload
- Start date
bioload
Having moments of clarity
Thanks for all the feedback everyone. Just to clarify, I did modify the design of the DSB from the original flow through design I had originally planned on doing. Water was fed using a maxijet 400 OVER the top of the bed. The drip was only used to obtain a sample from within the bed for testing. Could this drip have been enough to introduce oxygen into the lower portion of the bed.....quite possibly, but I'm skeptical.
I removed the DSB yesterday and I'm planning on replacing the substrate with a sugar fine silica. If I'm able to locate my sieves I'll post the exact size, but it is very fine. Keep the suggestions coming for the rebuild.
On a side note I emptied the fish bowl of algae and sand I had on my desk. The sand in that bowl had already started turning gray and had a very strong odour. This bowl was filled roughly the same time as the DSB.
Not to get off topic...but
In the meantime I had some scrap pieces of acrylic lying around and put this little tank together over the weekend. I though I might have a look at how macroalgae would do while I rebuild DSB. There are a couple species of caulerpa and some chaeto. I filled the tank with water from my display and monitored the nitrate level over the past day. Lets see how long it will take to scrub the nitrate out of the water.
Setup
Day 1 - There is already a noticeable change in the nitrate level
I may need to start a new thread to track this one.
I removed the DSB yesterday and I'm planning on replacing the substrate with a sugar fine silica. If I'm able to locate my sieves I'll post the exact size, but it is very fine. Keep the suggestions coming for the rebuild.
On a side note I emptied the fish bowl of algae and sand I had on my desk. The sand in that bowl had already started turning gray and had a very strong odour. This bowl was filled roughly the same time as the DSB.
Not to get off topic...but
In the meantime I had some scrap pieces of acrylic lying around and put this little tank together over the weekend. I though I might have a look at how macroalgae would do while I rebuild DSB. There are a couple species of caulerpa and some chaeto. I filled the tank with water from my display and monitored the nitrate level over the past day. Lets see how long it will take to scrub the nitrate out of the water.
Setup
Day 1 - There is already a noticeable change in the nitrate level
I may need to start a new thread to track this one.
Amphiprion
Premium Member
Well, yes and no, with bio-advection possibly being specific vector-wise in an outward horizontal direction, from what I understand at least. What is the primary source/force of the advective movement you are referring to? Flow in the water column? I guess what I'm misunderstanding is how the advection is being driven in these circumstances where it accounts for such a large percentage of porewater flux. I mean, if it is wave and/or flow driven, we already know that most DSBs do best with as much flow as possible without disturbing the substrate too much. Just trying to figure out where it's coming from.
Amphiprion
Premium Member
Curious to see your results. I've had great luck with turf algae species.
I agree with what you are saying, this thread's experiment, in my opinion, has next to zero advection going on and thus only a few centimeters near the top are possibly actively removing nitrate. High flow would be a huge improvement and having critters would only help this particular situation. I believe it is possible through proper design to have a DSB effectively remove nitrate indefinitely without the aid of bioturbation.
Amphiprion
Premium Member
You're probably right, but I haven't seen a design that takes full advantage of that yet, though. It just doesn't seem as fun without the critters to me, though 
.
.blasterman789
New member
My point in adding deitrus is that it would force seed the substrate with required bacteria. In a typical tank your fish, snails and other critters crawling around stir things up and add bacteria. In an artificial DSB you typically don't have this. Just water flowing over the top.
This also might explain why in controlled experiments artifical DSBs didn't do too much - duh? I noted that in all these tests the tank envirnments were initially sterile. So, somebody is assuming that de-nitrifying bacteria are supposed to spontaneously evolve from substrate I guess.
Also, there has never been any confirmation that DSBs or plenums actually work, other than theory. However, de-nitrate coils have been tested and confirmed to reduce nitrate levels. You would logically conclude that a slow current through the DSB would replicate the environment inside a nitrate coil, but to a much larger scale. All were trying to do is entice bacteria to steal and oxygen atom from a nitrate molecule rather than use liberated oxygen in the water.
This also might explain why in controlled experiments artifical DSBs didn't do too much - duh? I noted that in all these tests the tank envirnments were initially sterile. So, somebody is assuming that de-nitrifying bacteria are supposed to spontaneously evolve from substrate I guess.
Also, there has never been any confirmation that DSBs or plenums actually work, other than theory. However, de-nitrate coils have been tested and confirmed to reduce nitrate levels. You would logically conclude that a slow current through the DSB would replicate the environment inside a nitrate coil, but to a much larger scale. All were trying to do is entice bacteria to steal and oxygen atom from a nitrate molecule rather than use liberated oxygen in the water.
wayne in norway
New member
', but I haven't seen a design that takes full advantage of that yet, though' - DSB in a dark bucket does it.
Also, there has never been any confirmation that DSBs or plenums actually work, other than theory. - Pardon? I tinhk there is plenty of work both experimental and anecdotal. You can try it yourself with the afore stated dsb in a bucket design that relies almost purely on advective flow to feed bacteria,or you can ask the nice people I linked to on page 1., one of whom is doing her pHd on nutrient and oxygen flux in sediments. You could also ask Jaubert or look at his research.
A fast current over a sandbed will produce a slow current inside it. Pushing water quickly over the top will move water slowly thro' it. The top few cms will receive more oxygen as there is more flwo and fresher water, plus some help from diffusion. As you go down into the sandbed there will be a useful zone of reduced oxygen, and finally a layer with no oxygen at all where nitrate is reduced to ammonium. The trick is to maximise the gap between bottom of the oxygen rich zone and the top of the oxygen free zone. Reduced flow will make these shallower, but the useful volume in between will be reduced in volume. Increase the flow, they all move down in proportion and the actual thickness of the useful low oxygen zone will be increased.
http://ocean.fsu.edu/faculty/huettel/Huettel_page/Projects/NSF_FilterSands.html should be the start of some interesting reading for you..
Also, there has never been any confirmation that DSBs or plenums actually work, other than theory. - Pardon? I tinhk there is plenty of work both experimental and anecdotal. You can try it yourself with the afore stated dsb in a bucket design that relies almost purely on advective flow to feed bacteria,or you can ask the nice people I linked to on page 1., one of whom is doing her pHd on nutrient and oxygen flux in sediments. You could also ask Jaubert or look at his research.
A fast current over a sandbed will produce a slow current inside it. Pushing water quickly over the top will move water slowly thro' it. The top few cms will receive more oxygen as there is more flwo and fresher water, plus some help from diffusion. As you go down into the sandbed there will be a useful zone of reduced oxygen, and finally a layer with no oxygen at all where nitrate is reduced to ammonium. The trick is to maximise the gap between bottom of the oxygen rich zone and the top of the oxygen free zone. Reduced flow will make these shallower, but the useful volume in between will be reduced in volume. Increase the flow, they all move down in proportion and the actual thickness of the useful low oxygen zone will be increased.
http://ocean.fsu.edu/faculty/huettel/Huettel_page/Projects/NSF_FilterSands.html should be the start of some interesting reading for you..
^How funny is that article. I've been to St. George Island and on that beach, and I've been to Apalachicola, too of course, FSU is my alma mater.....
Why create a sand bed so deep that the bottom layer reproduces the ammonia which was broken down by the upper layers? Why not make a sand bed shallow enough that there is no anaerobic layer for ammonia production? along the lines of 3-4" with good flow?
of course, FSU is my alma mater.....Why create a sand bed so deep that the bottom layer reproduces the ammonia which was broken down by the upper layers? Why not make a sand bed shallow enough that there is no anaerobic layer for ammonia production? along the lines of 3-4" with good flow?
Similar threads
