corals b 4 bills
New member
When theres a question of algae I start at the beginning. Could there be somthing in the sand you bought? or I've heard of things like concrete inside of the live rock. look into this.
Dsb's work, what makes them work best?
- Thread starter barryhc
- Start date
beachroadbum
Premium Member
Hey Now,
Thanks for the reply kbmdale. Yeah I won;t be adding a fish for a long while yet. I just had to get some corals in there. Water paramaters are great and there are a ton of worm tracks which is a good sign. I just love the life you get with a DSB. It's so natural.
take care,
jared
Thanks for the reply kbmdale. Yeah I won;t be adding a fish for a long while yet. I just had to get some corals in there. Water paramaters are great and there are a ton of worm tracks which is a good sign. I just love the life you get with a DSB. It's so natural.
take care,
jared
I like your definitions here joefish. Boy have you people been busy here!!
It seems that the definition of a sand bed is still highly variable, and will likely stay that way. My point here is that, that variability may very well have contributed to some of the difficulties that people have had.
4" to 6" seems to be the common "minimum" depth. I guess I'd call it 5".
The particular substrate grain sizes and composition are very likely to have a significant effect as well.
Most sand beds are using rather fine sand as has been "reccomended", and this is usually "southdown", which is generally considered to be a mix of "mud" ( .05 to .125mm ) up to 4mm "gravel", or a straight grade of "oolitic" sand ( usually .1 to 1.2mm ). There are of course other variations.
I think the "exclusive use" of these finer muds and sands, has likely contributed considerably to the "sand-storm-problem", and other problems, and it needn't be the case.
Surely, these finer grains contribute to a very large surface area which is beneficial to large bacterial populations, and they are also touted as improving the buffering capacity of the substrate, which is probably true as well, but may not be as significant or beneficial as we have been lead to believe.
The fine grains are also claimed to "reject" detritus better than larger grains, and "on the surface" this would appear to be true, but in the larger picture of our complete reef system, I'm not so sure of this.
Here is my take on the fine grains. Yes, they definitely increase the surface "area", but is this really the "AVAILABLE" surface area? Most if not all of the experts have stated that the aerobic activity is limited to a very shallow depth in these fine grains.
This is because "advection" flow is extremely low in fine grains, and nutrient processing remains "shallow" within the depth that nutrient migration and diffusion can occur.
So, fine grains may actually "limit" the depth, and therefore the Available surface area that aerobic bacterial populations can occupy.
Further, within our reef tanks, the reduced flow that is often times used to avoid sand storms, also reduces advection flow at the surface of the sand, and even worse, can in some cases, allow organic solids to remain in contact with the surface, where they are processed, and "sink".
Now comes the "composition" of the sand or substrate. Araganite has been highly "touted" over at least the last several years, as "the best" for "buffering substrates". True or not, I am not yet convinced that this buffering capacity is as high as we have been led to believe, and additives of some type are usually required.
The unfortunate thing is that substrates that "buffer", do so by dissolving, and the first consequence of this is that the already fine grains become "even finer". I think that there is plenty of evidence available to support the notion that finer grains that are dissolving are more prone to crystalizing and "clumping".
In some cases this crystalizing can be the result of pH fluctuations that are likely to occur as the result of mixing, siphoning, stirring, etc. Also, Araganite is purported to have a goodly bit of Phophate bound up in it to begin with, and this phosphate at whatever level it is present, is certainly released when the calcium and carbonate buffers are released.
So GEE, am I bashing sand beds here? ABSOLUTELY NOT !!!!
Still, whatever goes on in a sand bed is something, or should I say, many things, that we need to understand.
I am certainly not an expert on this by any stretch, but I have done a tremendous amount of research on the subject, and this thread is part of it.
Ok, what to do, if any of this is true? Well, again, my take on this is that the finest grains might be best avoided in the display tank, where we are looking for longevity and ease of maintanence. I'm only talking about the finer "mud" here ( up to .2mm ).
Also, some "fine gravel" ( .5 to 2mm ) at the surface, will certainly reduce any sand storm potential to the point of "managability". Up to an 1 1/2" depth of this seems good, then your finer sand underneath. I bounced this idea off of Anthony Calfo a while back, and he stated that it would not cause a problem to bacteria or "fauna" either.
Now of course, the "fauna" and other sand critters as well as sand animals will have their effect here as well, and this is quite impotant in my opinion, both for the health of the bed, and the sand animals themselves.
Still, I think we might want to restrict access of the larger animals to the top layer, and not have them mess so much with the finer denitrifying sand below. A critter screen of 4 to 6mm openings might accomplish this very well.
I do have this arrangement in my own tank, but it has only been operating for 11 mos. and so, cannot be used as an example of success. I have run well over 60 X flow with this arrangement, and without any sand-storm or other difficulty.
This is what I have learned and observed thus far, but that does not make it right or correct. I am here to learn more, just like everyone else.
Lots of great posting here, Thank you all!! > barryhc
That's enough to kill a DSB right there.
4" is marginal, IMO. I went for 6". That does take up a lot of tank space, though. I'm not sure how many people want to buy (or have on hand) a tank that's an extra 6" to accomodate a sand bed.
The fact that removing the refugium seemed to help is also bizarre, and points to something strange happening, if the correlation is actually causal, which it might not be, either for the refugium or the DSB.
You might disable part of the bed for some period if your maintenance kills off animals or pumps oxygen into the lower layers. The visible effects, if any, depend on a lot of factors. If the tank have a large macro-algae refugium, you might never notice. I'd avoid disrupting the sandbed, in general, but moving around rock has never been a problem for me.
Yes, really, it was most likely very bad.
I think that's another pitfall of DSB systems. When I have an algae problem, I have to live with it longer than I would with a SSB or DSB system. The idea behind them is to use more biology to solve problems, but biological systems work on their timescale, not ours.
Another issue here might be more fundamental. A DSB system is targeted at keeping more organisms alive. I think it's quite possible that problem algae are more likely to be removable or more easily removed from a BB system, where you can do manual maintenance to starve them out pretty rapidly. Same possibly with Aiptasia. This is only a thought that I'm throwing out, though.
I think that's another pitfall of DSB systems. When I have an algae problem, I have to live with it longer than I would with a SSB or DSB system. The idea behind them is to use more biology to solve problems, but biological systems work on their timescale, not ours.
Another issue here might be more fundamental. A DSB system is targeted at keeping more organisms alive. I think it's quite possible that problem algae are more likely to be removable or more easily removed from a BB system, where you can do manual maintenance to starve them out pretty rapidly. Same possibly with Aiptasia. This is only a thought that I'm throwing out, though.
<a href=showthread.php?s=&postid=6461731#post6461731 target=_blank>Originally posted</a> by joefish
If I saw any grey (detritus I would siphon that little area out . And when I said stired I ment just the surface so any detritus would be free floating .
Was that also bad ?
Probably not that bad, although it is better handled with sand critters and higher flow. Don't do anything to the sand bed.
There are various methods of maintnence, and they are workable, but I prefer critters, flow, and do nothing to the sand bed.
Your tank was really beautiful, even with the algae, and still is as a BB. I don't know what the algae was or what, if any, critters would help to remove it, but I can't see how to call it a failure.
Good luck with the new one. > barryhc
kbmdale
In Memoriam
ok so lets look at what barry said above
the norm is to get a fine sand and add 4" to the bottom of the tank. Now barry said that with the fine sand there is a shallower aerobic area. lets say the first 1", then there is a 3" anaerobic area underneith. Is it possable that 1" is not enough surface area to effectively filter, and will only supply a small amount of the anaerobic area. So back to what I said 2 pages ago.
What if you make a 5"->2"->5" dsb...the 5" area's at each end and the 2" in the middle. Then you are effectively adding surface area to the aerobic area which should equal out the same amount of anaerobic. Does this make sense. Like I said the DSB tanks I have seen longevity out of all seem to have high and low spots in the tank. Maybe there is a relationship to it whether it be by accident of by design.
the norm is to get a fine sand and add 4" to the bottom of the tank. Now barry said that with the fine sand there is a shallower aerobic area. lets say the first 1", then there is a 3" anaerobic area underneith. Is it possable that 1" is not enough surface area to effectively filter, and will only supply a small amount of the anaerobic area. So back to what I said 2 pages ago.
What if you make a 5"->2"->5" dsb...the 5" area's at each end and the 2" in the middle. Then you are effectively adding surface area to the aerobic area which should equal out the same amount of anaerobic. Does this make sense. Like I said the DSB tanks I have seen longevity out of all seem to have high and low spots in the tank. Maybe there is a relationship to it whether it be by accident of by design.
kbmdale
In Memoriam
<a href=showthread.php?s=&postid=6452701#post6452701 target=_blank>Originally posted</a> by npaden
I guess my 4 1/2 year old high flow SPS dominated DSB tank is inappropriate then?
look at the levels of the sand in this tank. I have seen several others like it that have been successful in the long term of 3+ years. Your right could be nothing, but could be a clue easily overlooked.
I think we need to look again at the "nitrification" and "denitrification cycles". Nitrification is performed predominantly in the upper level of a sand bed. The depth of this upper level is not well described in most literature regarding Marine Environments ( especially "captive reefs" ), and rightly so.
The effect of infauna ( the little guys ), and even more so of burrowing and sifting animals, has a huge effect on the depth of oxygenation, and without specific "animal-type-and-population" data, no depth of oxygenation can be predicted, or obviously specified.
Certain "recipes" have been given to the hobby, and touted as "the correct way" to set-up a sand bed. When strictly adhered to, these recipes can work quite well. Elsewise, who knows, and I doubt that these reccomendations have been followed all that closely by many aquarists.
Also, some of these "recipes" may work for a community tank, and might not be the best scenario for SPS dominated tanks, and as of recently, possibly "Dendros" as well.
Several of these recipes, specificly require that "sifting animals" are not allowed, much to my great dissatisfaction, and further, that burrowing animals will "destroy the functionality" of a deep sand bed, and again, I just can't swallow this restriction. I just don't think that it "has to be" the case.
So for nitrification, this occurs mostly in aerobic areas of the bed where nutrients are available for our familiar bacteria to process. Sifting and burrowing animals have the effect of keeping this area aerobic as well as avoiding "clumping" and keeping the surface "turned" so that algal mats of various kinds do not take over. Some of these also deplete the "infauna" population and this can be a detriment to the system depending on . . . .
Well, then the infauna help to bring dissolved nutrients into the sand bed for processing, and then help to export them when they are eaten, and then "up the chain" until poop is avilable in the water column for skimming or mechanical removal.
Denitrfication is far less well understood by a large portion of the reef keeping community. Very many aquarists still believe that denitrification occurs in the Anaerobic "zone" ( or areas ) of the sand bed, and this is really quite inaccurate. Many aquarists are well versed in this I realize, but many are not, and more so as we look not so far back in time.
The first and most recognized function of denitrification is the reduction of Nitrite into Nitrate and various other results. This process is carried out primarily in a very thin layer or space in the substrate depth.
It need not be vertical either, but it is described in most studies, as occuring in a "layer" as thin as .5mm between the aerobic and anaerobic zones, and "usually occuring at a depth of approx. 5 to 10 mm's deep in fine sediments that are not disturbed by sifting or burrowing animals".
This "zone" has been described with various terms by both hobbyists and experts alike, often times in contradictory fashion, in all directions, and has been the source of an unbelieveable amount of confusion. I know this for sure, from all the research I've done trying to understand it myself, and the only terms that are not confused in this regard, are "low oxygen", and "Hypoxic".
I like the "low oxygen" term myself, because you just can't confuse that term.
In the "low oxygen" environment, NON-OBLIGATE ( faculative ) Anaerobic bacteria are responsible for reducing Nitrite to Nitrate and other compounds, and this occurs in a ( usually ) very thin layer as stated before.
How thin is this layer actually, especially when "disturbed" or modified by sifting and burrowing animals? I don't know, after 14 mos. of investigation, I'm still trying to find out.
It is now below this "low oxygen" zone, that other processes are carried out by OBLIGATE Anaerobic bacteria, and it is here where Nitrates and other nutrients and compounds are processed into nitrogen gas supposedly, which is somewhat controversial for some reason, and hydrogen sulfide ( again contrversial ), Phosphates "bind and leach", heavy metals "sink", and again, guess what, all controversial.
I believe that all these processes occur in a deep sand bed, to one degree or another, and likely, different in every tank. It is the DIFFERENT in every tank part that has gotten us into this discussion, I'm sure, along with many other things.
I've gotten "long winded" again, not really intending to do so, sorry about that. And I'm no expert, but these again are my observations from very much research.
By the way, algal mats, "binding and leaching", clumping, "sinking", and sifting and burrowing critters, can all be dealt with using a bit of consideration IMO.
Any similar ( or not ) observations?
Happy Reef Keeping ! > barryhc
The effect of infauna ( the little guys ), and even more so of burrowing and sifting animals, has a huge effect on the depth of oxygenation, and without specific "animal-type-and-population" data, no depth of oxygenation can be predicted, or obviously specified.
Certain "recipes" have been given to the hobby, and touted as "the correct way" to set-up a sand bed. When strictly adhered to, these recipes can work quite well. Elsewise, who knows, and I doubt that these reccomendations have been followed all that closely by many aquarists.
Also, some of these "recipes" may work for a community tank, and might not be the best scenario for SPS dominated tanks, and as of recently, possibly "Dendros" as well.
Several of these recipes, specificly require that "sifting animals" are not allowed, much to my great dissatisfaction, and further, that burrowing animals will "destroy the functionality" of a deep sand bed, and again, I just can't swallow this restriction. I just don't think that it "has to be" the case.
So for nitrification, this occurs mostly in aerobic areas of the bed where nutrients are available for our familiar bacteria to process. Sifting and burrowing animals have the effect of keeping this area aerobic as well as avoiding "clumping" and keeping the surface "turned" so that algal mats of various kinds do not take over. Some of these also deplete the "infauna" population and this can be a detriment to the system depending on . . . .
Well, then the infauna help to bring dissolved nutrients into the sand bed for processing, and then help to export them when they are eaten, and then "up the chain" until poop is avilable in the water column for skimming or mechanical removal.
Denitrfication is far less well understood by a large portion of the reef keeping community. Very many aquarists still believe that denitrification occurs in the Anaerobic "zone" ( or areas ) of the sand bed, and this is really quite inaccurate. Many aquarists are well versed in this I realize, but many are not, and more so as we look not so far back in time.
The first and most recognized function of denitrification is the reduction of Nitrite into Nitrate and various other results. This process is carried out primarily in a very thin layer or space in the substrate depth.
It need not be vertical either, but it is described in most studies, as occuring in a "layer" as thin as .5mm between the aerobic and anaerobic zones, and "usually occuring at a depth of approx. 5 to 10 mm's deep in fine sediments that are not disturbed by sifting or burrowing animals".
This "zone" has been described with various terms by both hobbyists and experts alike, often times in contradictory fashion, in all directions, and has been the source of an unbelieveable amount of confusion. I know this for sure, from all the research I've done trying to understand it myself, and the only terms that are not confused in this regard, are "low oxygen", and "Hypoxic".
I like the "low oxygen" term myself, because you just can't confuse that term.
In the "low oxygen" environment, NON-OBLIGATE ( faculative ) Anaerobic bacteria are responsible for reducing Nitrite to Nitrate and other compounds, and this occurs in a ( usually ) very thin layer as stated before.
How thin is this layer actually, especially when "disturbed" or modified by sifting and burrowing animals? I don't know, after 14 mos. of investigation, I'm still trying to find out.
It is now below this "low oxygen" zone, that other processes are carried out by OBLIGATE Anaerobic bacteria, and it is here where Nitrates and other nutrients and compounds are processed into nitrogen gas supposedly, which is somewhat controversial for some reason, and hydrogen sulfide ( again contrversial ), Phosphates "bind and leach", heavy metals "sink", and again, guess what, all controversial.
I believe that all these processes occur in a deep sand bed, to one degree or another, and likely, different in every tank. It is the DIFFERENT in every tank part that has gotten us into this discussion, I'm sure, along with many other things.
I've gotten "long winded" again, not really intending to do so, sorry about that. And I'm no expert, but these again are my observations from very much research.
By the way, algal mats, "binding and leaching", clumping, "sinking", and sifting and burrowing critters, can all be dealt with using a bit of consideration IMO.
Any similar ( or not ) observations?
Happy Reef Keeping ! > barryhc
Sindjin
New member
I think more research and emphasis needs to be focused on Phosphates in the DSB. Phosphates really dont get broken down...just pushed further into substrate... hence, like Bomber always said, that is why we have phosphate mines in Florida.
Yes, the DSB is a great addition to aid in denitrification but the storage of phosphates needs to be examined as I believe PO4 could be released slowly...causing algae blooms, etc.
I run a BB in my 120. And no.... I do NOT intend to change this thread to a DSB vs BB thread. A few weeks ago I used a turkey baster and sucked up a dime sized pile of detritus from the bottom. It accumulated ONE DAY after I siphoned the tank and changed some water. I placed that sample in a cup and immediately tested that sample for PO4. It read 3.0ppm. I then ran a general test of the water column which read .06ppm. This showed me that a brand new pile of debris emmitted a ton of PO4. Now...what would happen to it if I was running a DSB? It would have sunk into the bed where it would remain and build up.
Right? Im asking because this aspect of DSB reef keeping really hasn't been answered...at least from what I have read, and I would love to learn more about it.
Yes, the DSB is a great addition to aid in denitrification but the storage of phosphates needs to be examined as I believe PO4 could be released slowly...causing algae blooms, etc.
I run a BB in my 120. And no.... I do NOT intend to change this thread to a DSB vs BB thread. A few weeks ago I used a turkey baster and sucked up a dime sized pile of detritus from the bottom. It accumulated ONE DAY after I siphoned the tank and changed some water. I placed that sample in a cup and immediately tested that sample for PO4. It read 3.0ppm. I then ran a general test of the water column which read .06ppm. This showed me that a brand new pile of debris emmitted a ton of PO4. Now...what would happen to it if I was running a DSB? It would have sunk into the bed where it would remain and build up.
Right? Im asking because this aspect of DSB reef keeping really hasn't been answered...at least from what I have read, and I would love to learn more about it.
I'm not sure about that. Isn't the idea to have enough flow to keep the presumably lighter-than-sand detritus up off the sandbed? I know I have my flow set to shoot down then over the sand..set just right to not make an empty hole in the back of the bed, but still flowing out over the bed, then back up. (Granted, this is much easier to do in a hex tank I think, due to it's shape).
Also, wouldn't well cured live rock (some might say cooked) help with this aspect...much less detritus shedding from rocks = less buildup, if any in the DSB = less or no chance of "leeching" phosphates.
What do you think?
Amphiprionocellaris
New member
First, a thought about algae...
The presence of algae can't really be used (IMO) as a sign of DSB (or any system) failure. Algae is a natural part of the reef (as the zooxanthellae in your corals would tell you), and shouldn't really be considered a problem until it affects coral health (leaching, direct overgrowth, etc.). If it detracts from the appearance of the tank, it should be considered a nuisance, not a problem (very fine difference). There are, IMO, two primary reasons that algae does not totally dominate the natural reefs.
First, almost all the space is taken up by more efficient competitors (coral and coralline algae). That is why more northerly coral collections (not true reefs anymore) are [naturally] dominated by algae rather than coral: conditions are not as favorable for the coral, so the algae moves in.
Second, the reef has a much higher concentration of herbivores than our tanks. Granted, it can be very difficult to provide proper housing for a school of tangs (actually, "impossible" might be more appropriate). On the reef, algae is grazed before it can even grow to any great extent (hence the evolution of coralline algae, which is grazed only by a very small part of the herbivore population). The plethora of herbivores found on the reef is, to me, evidence that there is an intense amount of algal growth that is not apparent because the algae is so quickly consumed.
I think it is those two factors (lack of near-natural coral coverage and lack of herbivores) that lead primarily to algae problems in otherwise healthy tanks. Fixing these two factors can sometimes be difficult (it's hard to get 80% coral coverage in an algae dominated aquarium), but I think that's enough off-topic for now. My point is simply that algal growth shouldn't automatically be associated with DSB failure.
Now, onto DSBs. One thing that I think really makes or breaks a system is the ability of the natural infauna to survive. Because most home aquaria have very small sand areas (ie bottoms), they simply can't have large-enough sand beds to support the ecosystem. This leads to gradual die-off. This is easily circumvented by getting a "booster" for the infauna (unfortunately, I don't know off the top of my head where to get the starter packs). This also might be why larger systems seem to do better (more surface=more survivability of infauna). This [macroscopic] infauna is necessary for dealing with wastes other than nitrogen compounds. Thankfully, though, the nitrogen-processing bacteria tend to reach equilibrium fairly quickly, so that aspect of the DSB is never really compromised by faunal extinction.
That's certainly not the only factor, though. Increased water flow certainly helps (helps not just the DSB: it is more conducive to coral growth, see above about "algae"). Stirring shouldn't be necessary with healthy infauna, but it might become necessary. If you absolutely must stir, I think it's best to just stir small (very small) portions at a time, so as not to disrupt things to much. Healthy DSBs, though, need no stirring.
The presence of algae can't really be used (IMO) as a sign of DSB (or any system) failure. Algae is a natural part of the reef (as the zooxanthellae in your corals would tell you), and shouldn't really be considered a problem until it affects coral health (leaching, direct overgrowth, etc.). If it detracts from the appearance of the tank, it should be considered a nuisance, not a problem (very fine difference). There are, IMO, two primary reasons that algae does not totally dominate the natural reefs.
First, almost all the space is taken up by more efficient competitors (coral and coralline algae). That is why more northerly coral collections (not true reefs anymore) are [naturally] dominated by algae rather than coral: conditions are not as favorable for the coral, so the algae moves in.
Second, the reef has a much higher concentration of herbivores than our tanks. Granted, it can be very difficult to provide proper housing for a school of tangs (actually, "impossible" might be more appropriate). On the reef, algae is grazed before it can even grow to any great extent (hence the evolution of coralline algae, which is grazed only by a very small part of the herbivore population). The plethora of herbivores found on the reef is, to me, evidence that there is an intense amount of algal growth that is not apparent because the algae is so quickly consumed.
I think it is those two factors (lack of near-natural coral coverage and lack of herbivores) that lead primarily to algae problems in otherwise healthy tanks. Fixing these two factors can sometimes be difficult (it's hard to get 80% coral coverage in an algae dominated aquarium), but I think that's enough off-topic for now. My point is simply that algal growth shouldn't automatically be associated with DSB failure.
Now, onto DSBs. One thing that I think really makes or breaks a system is the ability of the natural infauna to survive. Because most home aquaria have very small sand areas (ie bottoms), they simply can't have large-enough sand beds to support the ecosystem. This leads to gradual die-off. This is easily circumvented by getting a "booster" for the infauna (unfortunately, I don't know off the top of my head where to get the starter packs). This also might be why larger systems seem to do better (more surface=more survivability of infauna). This [macroscopic] infauna is necessary for dealing with wastes other than nitrogen compounds. Thankfully, though, the nitrogen-processing bacteria tend to reach equilibrium fairly quickly, so that aspect of the DSB is never really compromised by faunal extinction.
That's certainly not the only factor, though. Increased water flow certainly helps (helps not just the DSB: it is more conducive to coral growth, see above about "algae"). Stirring shouldn't be necessary with healthy infauna, but it might become necessary. If you absolutely must stir, I think it's best to just stir small (very small) portions at a time, so as not to disrupt things to much. Healthy DSBs, though, need no stirring.
