Care to solve a mystery?

[Cosmic]

I thought that might get your attention.

I recently had to tear down my 5+ yr established 75 reef tank due to a popped seal in the front left bottom corner. In the process, I had to remove the entire sand bed, which was about 4" thick, and had a nice anaerobic and anoxic zone present. The lifeforms in said bed were about wiped out by a pair of peppermint shrimp added a few months back to handle an aptasia infestation. Goes to show why I prefer something other than a natural predator to handle the tasks :?

Other than tearing this bed up, I saved all the original water (what didn't leak out the bottom that is) and Live Rock, and even kept the sand I took out, draining off the muddy water that pooled at the top of the buckets.

I was also in the process of bringing online a brand spanking new refugium, that contained no seeded sand, and just about 10Lbs of rock that came from the existing sump that was ultimately removed. In went a handful of various Macros donated by a fellow local reefer (Frick-n-Frags from RAG), and a few more Lbs of fresh rock a few days later.


OK, you say, but what's the mystery? Well, I ran tests daily to track any ammonia and nitrite levels that should spike, and none were EVER present. In fact, I managed to get a 100% survival rate from the transfer, even though the back of the new tank got 2 coats of paint in 3 hours, and water in it the 4th hour

My question to you is....
Where did they go, and why didn't I experience a cycle?
So put on your thinking caps and let's see what you can come up with
Feel free to ask questions if you think it will help you come up with a solution. For example, I didn't mention refugium size (55 gal), lighting, livestock, etc.


Cos

 

[MnReefMan]

one question how much of the water was saved from the origional tank?


edit okay you saved it all.....

 

[Cosmic]

I was able to save 60 gallons and had to add roughly 25 gallons of freshly made saltwater to accomodate the addition of the refugium.

 

[mojoreef]

Hey Cos great to see ya over here. Mystery hmmm...ok I will take a stab at it.
Hmm you know I dont see why thier would be a cycle. A cycle is basically another way of saying establishing a bacterial population. Bacteria for converting ammonia to nitrite and nitrite to nitrate. Carrying over your LS and LR and some established water you basically brought your own. SO thier should be no real reason to have to establish any.
Now I wouold be putting to much pressure on the system as I am pretty sure you did wipe out a good amount of them, so give them some tie to build back up.
Now on another note your anoxic bacteria is toast, but really they dont serve to much of an important role in our tanks (which is what makes DSB's kinda useless). Your anerobic bacteria (which will process nitrate to nitrogen gas) is faculative, as in it perfers oxygen, but when oxygen is depleted it will fix nitrate ( thus denitrifing).

anyway thats my take


mike

 

[MnReefMan]

i got an idea mojo let get the spankster in here im sure he could solve it in ohhh 300 posts.....lol

 

[Cosmic]

i got an idea mojo let get the spankster in here im sure he could solve it in ohhh 300 posts.....lol

Isn't that part of the reason we're over here?

I can understand your thinking Mike, but don't you think that , SINCE a DSB acts as a nutrient sponge ultimately, that I would have "squeezed" the sponge out when I tore up the bed and redid everything? This would mean expelling ALL that junk that has bulding up down in my bed for the past, umm.... 4 years?

With the way that bed looked (and smelled) upon tearing it down, I fully expected to have at LEAST a minor spike of ammonia or nitrite. However, my corals didn't so much as flutter after the whole ordeal :shock:

Matter of fact, I haven't even noticed a nitrate spike yet. Granted, all the various macros in the refugium most likely handled those with the slow flow rate I have through there.

But what about a rise in phosphates? This is yet another category that rose very insignificantly. I am now wiping down my display glass once a week instead of every other On a side note, the algae has turned from brown diatom (before) to green micro (after). I don't run a DI unit on my RO, so silicates usually get through, explaining the diatoms. The sudden appearance of green micro therefore must have come out of the bed, and is being handled in a natural manner by the algaes.

Don't get me wrong...Overall, I'm ecstatic with how well the transition went over. I had fully expected to see at least some bleaching in my acros, but nada (**Knocks on wood**). I just thought that this would be a good starting discussion to get the board off on it's feet

Glad to be invited Mojo

Cos

 

[mojoreef]

I just thought that this would be a good starting discussion to get the board off on it's feet

It still is

SINCE a DSB acts as a nutrient sponge ultimately, that I would have "squeezed" the sponge out when I tore up the bed and redid everything? This would mean expelling ALL that junk that has bulding up down in my bed for the past, umm.... 4 years?

Se now here is where it gets tricky. I dont think you can call it a Nutrient sponge, You have to break it down a little more.
When the areobic zone of the bed was removed, your going to get a bit of waste and general detritus, but if you had a good amount of critters this crude was probibly broken down to micro particles (thus the brown Juice).
The anerobic zone, which is really not a zone (its just the area where the sediments goes from oxygenated to non oxygenated). Your main thing here is Nitrate, you will only really have one type of worm that can transverse into the lower depths of this area and the balance of the life here is bacteria, as mentioned above the bacteria can survive fine with or with out oxygenated water, so no real death from this.
The anoxic zone below (water devoid of oxygen) is habitated by only bacteria and its biproducts. This is where you will get the most polution from. The bacteria here will die once they are subjected to oxygen( so a bit of death but not a ton. The balance of products in this zone are non nitrogen based (since all the upper zones will only process nitrogenious waste). So from here you will get stuff like inorganics, bacterial shells, microscopic particle dust, sulphides (at various stages), methanes (at various stages) enzynes, microbes (and all other methods used by bacteria to eat). Draining off the muddy water probibly helped remove most of what was in this zone. Couple this with a healthy LR (denitrifier) and a micro algae refumium (probibly bound alot of free nutrients and P.) you didnt get an impact.
On the other hand if you didnt wask out the lower section of the bed prior to putting it back in you arent really starting from scratch. Bacteria in all depth will bind to the sediment and create bio films that dont just fall off, so they are still thier or at least the enznes and suck are. What you did was to get rid of the material that resides between the sand grains (which is really good and does free up alot of the clogged bed).

Keep an eye on it bud, you may not be out of it yet. P is the one that might come back over the next week or to.

Sounds like a good transition though, glad nothing was lost.


Mike

 

[tdwyatt]

originally from Mojo's post:
What you did was to get rid of the material that resides between the sand grains (which is really good and does free up alot of the clogged bed)... ...Keep an eye on it bud, you may not be out of it yet. P is the one that might come back over the next week or to...

Most of the "trash" that is end detritis will be in the "brown stuff" that was suspended in the removal process. This is the stuff that ends up in the substrate of DSB's when it has been processed through 10 to 12 gut cycles of creatures in the food chain. Supposedly there is nothing left to "squeeze" out of it in terms of carbon or nitrogen, only mineral ash and metals in insoluble form. At this point, bacterial biomass usually locks the metals into cell wall and other deposition sites within the cytoplasm of the bacteria, resulting in the final resting place for these substances (unless they are consumed by some other creature grazing the sandbed for bacteria, unlikely in the regions where this occurs). This is where long-term buildup of metals and trace elements come from in the DSB, prolly the ultimate limiting factor in DSB longivity in closed systems. By limiting the inputs of substances that lead to this end detritus and /or exporting these substances by locking them up in biomass (especially macroalgal biomass or intermediate "top down" grazers line Holothurian spp sea cukes and tangs, etc.), the DSB can be made and managed for an indefinite term. If DSB stands for "dirty sand bed" in a system, it will have a limited lifespan and may require refurbishment or replacement once it's ability to act as a sink has been exceeded.

As far as the phosphate goes, if you used a good portion of the old water to reestablish the system, that water would have been saturated in respect to the phosphate levels, and the poorly soluble phosphate in most sand beds (usually Ca Phosphate) would most likely stay in the sandbed. Unless there was a DRAMATIC drop in pH (like say, oh 4.0 or lower), little of the phosphate will go into solutioin, if at all. It is possible for some deep regions of deep sand beds to produce low pH, but not low enough to be of significance unless it can change the entire water column's pH. The sulubility increase in DSB's would be limited to the region where the pH is lowered by the anaerobic bacterial activity, and by that token, would be self limiting. Once the phosphate ions begin to diffuse out of that area and the surrounding free interstitial water (between the grains of sand) becomes of higher pH, the phosphate will precipitate back out of solution, and by doing this, increases the pH of THAT area ( the phosphate becomese a proton acceptor and takes the proton out of solution); once again, limiting the low pH zone to the area of the deep part of the sand bed.

 

[mojoreef]

Solid Post Tommy, lots of good info. In the P remember you can have anoxic micro zones happen a 1/4 inch down in a bed, depending on the situation. ANd in most closed system we run, that is more the norm then the other.

 

[Cosmic]

Sorry I haven't been back in a few days, RL has kept me busy lately.

I had pretty much neglected testing the past few days, but I managed to run a set again this morning, and levels have still remained constant, with the exception of that slight rise in P<.05.

However, I have noticed other, more problematic (possibly?) things, such as a blue-tip stag bleach out quickly over the past week. I first thought RTN, but the tissue wasn't sloughing off like it does with RTN. It was more just a (slow) bleach over a weeks time. Closer inspection has discovered the dreaded(?) acro mites, or herpactitoid amphipods, that everyone has been ranting about. I'm still undecided as to whether they are actually pests or not, hence my indecision in calling them "dreaded pests"

tdwyatt...
So in layman's terms, you are saying I have "rinsed out" my DSB sponge, and now it has a much renewed life ahead of it? What sort of drawbacks would you see from from doing this on a continual as-needed basis, so that people would not have to replace them with new sand? With a regular water maintenance schedule, thereby diluting concentrations of said metals, inorganics, etc, I could see where a DSB would be capable of a very long lifetime. Again, it all comes down to good husbandry, but this applies to any sort of filtration we use. If you input the nutrients, you better have a good means of exporting it.

As for PO4, I can understand your reasoning behind why it's being rebound in the bed instead of being released, but what I don't understand is where this extra PO4 is coming from. I'm going to run some tests on my source water and see if that's where it is coming from. Other than tearing down the tank and setting it back up, I have not changed any routines that would lead me to suspect higher levels.

Cos

 

[tdwyatt]

tdwyatt...
With a regular water maintenance schedule, thereby diluting concentrations of said metals, inorganics, etc, I could see where a DSB would be capable of a very long lifetime. Again, it all comes down to good husbandry, but this applies to any sort of filtration we use. If you input the nutrients, you better have a good means of exporting it.

As for PO4, I can understand your reasoning behind why it's being rebound in the bed instead of being released, but what I don't understand is where this extra PO4 is coming from.Cos

On the longivity of the DSB, these are exactly my thoughts on the process. It does require good husbandry and it does require careful export as well and controlling imports to avoid the sinking of end-detritus. The problem arises when we depend on the bacteria solely (and sometimes unavoidably) to process organics in the sandbed. If you can both export macroaogae and use top down control of nutrients (grazers) to incorporate these substances in biomass of fishes, sea cucumbers, snails, etc, then the DSB is spared its repository sink role to some extent. I imagine that over time, given enough time, there is no way to avoid the eventual saturation of the dsb as a sink. The system I just took down was about 6 years 3 months old, and was still functioning well, with clean sand down as deep as 6cm, but the last 6 cm containing some sediments and dark mineral ash. I don't know exactly how long a closed system can be maintained without changing the dsb, I am not even sure that I can tell you when the point is reached that the sandbed is no longer viable as a filter, but I am sure that I do want DSB, if for no other reason, I like the creatures that utilize it as a home.

Still maintains long-term stability, and I like the natural look.

The phosphate can come from feeding of proteins alone, although flake is especially bad, it can come from the blender mush most of us like to use occasionally. The use of Calcium additives, especially kalkawasser at high doses will precipitate the phosphate as Ca phosphate, VERY insoluble in seawater, to the point that it becomes a permanent part of the substrate unless the pH drops below 4.0 I don't think that it will drive your water column to saturation, but many sources of
phosphate can, as I am sure you're aware of. Most likely it is an accumulation over time of organic phosphates that are slowly being released as the organic portion is either metabolized by the substrate or the organic part has decomposed in some other site (a particulate filter, LR, God forbid that you have bioballs, etc.).

hth

 

[Cosmic]

The problem arises when we depend on the bacteria solely (and sometimes unavoidably) to process organics in the sandbed

I can tell you ALL about this one, as a pair of peppermint shrimp/aptasia controllers decimated the life in my bed in short order (2 weeks time). Currently, there isn't much in the way of life in my display's DSB. Fortunately, because of the wave motion in the main tank, most of it settles out in the sump or refugium, which DOES have the critters still.

I don't know exactly how long a closed system can be maintained without changing the dsb, I am not even sure that I can tell you when the point is reached that the sandbed is no longer viable as a filter, but I am sure that I do want DSB, if for no other reason, I like the creatures that utilize it as a home.

I think the longevity of a bed is wholly inherent to that particular setup, and caretaker. There are simply too many variables to put an age limit on a DSB. Like you, I'm still a DSB advocate, unlike a few others we know
I have a hard time believing that all this natural life that sprouts from the use of a DSB can't be beneficial for the few drawbacks inherent to DSBS.

The phosphate can come from feeding of proteins alone, although flake is especially bad, it can come from the blender mush most of us like to use occasionally. The use of Calcium additives, especially kalkawasser at high doses will precipitate the phosphate as Ca phosphate, VERY insoluble in seawater, to the point that it becomes a permanent part of the substrate unless the pH drops below 4.0

I understand and am aware of all of these sources, but I had to rule them all out because they are static both before and after the tank tear down, IE they haven't changed practices. I feed the same amount as before, and I still dose Kalk daily as all evap water. I HAVE added a Ca reactor and gotten away from 2-parters though. Using the A.R.M. media, and haven't been able to find any statistical breakdown of it's contents yet. So there's a possibility I hadn't thought of.

God forbid that you have bioballs, etc.).

Yeah, God Forbid
I got rid of those about 5 yrs ago myself.

Cos

 

[mojoreef]

I'm still a DSB advocate, unlike a few others we know

OK now I have been a good boy and havent pooped on your DSB, even though everything else has
I am not against DSB's I just feel it is important that folks know both sides of the story, good and bad. This way if they choose to use one then they will know how to take care of it and what its limitations are. Now dont get me going I gave up antfarms when I was a kid, (sorry I have been dieing to get that one out )
In a well running DSB once you get passed the thin anerobic zone, thier are no real critters beyond bacteria and its associates. This anoxic zone serves no purpose for what we are keeping?? or am I wrong. YOur denitrification (that you are looking for ) happens i the anerobic layer and in truth can be anywhere in the bed beyond the anoxic zone. The areobic zone if where those precious bugs you love live. the anoxic zone is a stew of end product detritus, bacteria, enzynes, bacterial flock and so on reside. NOTHING down here does anything for your tank, what ever is done does not make it to the surface.
If you want denitrification and your beloved critters why not just have a Shallow sand bed, say 2 inches??? It will do everything you want. and when if gets dirty you can simply clean it (syphon or stir) the anerobic bacteria is Fuculative, so it wont die, it will simply fix oxygen unitl it runs out in that zone, then right back to nitrate. Life is good, easy and no long term worries????

Cos when you dug up that DSB you stired up a bunch of different stuff. Form sulphides to end products to inorganics and everything in between. rinsing out the dirty water probibly got rid of most, but who knows. I would keep the water changes going until you get passed the hump.


Mike

 

[tdwyatt]

originally posted by da mojo...
In a well running DSB once you get passed the thin anerobic zone, thier are no real critters beyond bacteria and its associates. This anoxic zone serves no purpose for what we are keeping??

I am not so sure on this any more, although I am swayed by the dark side (BBG...) I have decided not to completely leave the DSB concept for several reasons, one of which is the sulfate in proteins. Nitrates are converted by anaerobes, both facultative and obligatory types, but Sulfate may depend more on obligatory anaerobes (this is TOTALLY an opinion based of the location of the "black spots" we often see in DSBs.) The black spots we see in DSB's are the sites of sulfate cycles, and I am not even sure that they contribute in any way to the total health of the system. I know what stirring up the DSBs does to these locals, they end up reeasing toxic dissolved H2S, but when not disturbed this is limited to the areas where the cycle is occuurring and is not a contribution of toxuic substances to the water column, so what DOES it do??? Where does the sulfur molecule go?? Is this a beneficial thing? IS IT NECESSARY TO METABOLIZE THESE SULFATES? and would that be a contribution or a potential problem? I am researching it, as I cannot find much FACTUAL info or documentation on the topic in the literature on closed systesm (but there is a lot of speculative material out there ).

I don't want to pass on urban reef legends that promote non-factual info, but this is an area that may be of signignificance, I just do not know at this point, although the things that do occur do make the DSB VERY attractive to me as a reefer. It still will come down to what do you want to do with your system, and what do you want to keep, and how do you want to manage it? In my mind it is a lot easier to vaccuum out the DSB once every 4 years than it is to vaccuum the sand bed every month.

BTW Mike, I have fire ants here in the yard, Ambdro may take care of some of them, but I will dig you out a queen if you'd like to start yer own little captive system

 

[mojoreef]

LOL no thanks Tom I got an ant mound the size of a VW bug in the driveway.
I here ya TOm and going with a DSB is ok. It limits you on some stuf (flow, detritus removal, and of coarse the opther things we discussed) and it does have its benefits for sure.
On the sulphur cycle. Sulfur is oxidized by bacteria in the areobic zone by bacteria (Beggiatoa, Sulfolobus, Thiobacillus, Thiothrix) and also in the anerobic zone by bacteria (Thiospirillum, Thiocapsa, Chromatium, Chlorobium, Prosthecocloris).
Sulfur reduction goes on a little deeper by again bacteria. The end product of this reduction is Sulfide, not a real likable thing for a reef tank. The sulfur reducig bacteria fall in line right behind the nitrate reducers and just ahead of the methanogens. So thier presence could be anywhere in the bed depending on the situation. Another little scary thing with this cycle in a closed system is that after all the electron tranfers in this cycle (at the expence of ATP) one of 2 things is going to happen to that sufide. It will either be released into the enviroment or it will be absorbed by ammino acids. Neither of these 2 options seems very viable to me.



Mike

 

[tdwyatt]

Sulfur is oxidized by bacteria in the areobic zone by bacteria (Beggiatoa, Sulfolobus, Thiobacillus, Thiothrix) and also in the anerobic zone by bacteria (Thiospirillum, Thiocapsa, Chromatium, Chlorobium, Prosthecocloris)....

Man, SOMEBODY has been doing their homework!

Actually this is not unknown, especially in the natural environment, my concern is what is doing it in the closed systems, and why has it not turned toxic in DSBs??? We don't see these anaerobic sulfide reduction areas near the surface in reef tanks, it must be occuring in either totally anoxic microenvironments or in deep areas where obligatory anaerobes functioin. Still looking for the most likely culprit in a closed system...

HHHmmmmm....

 

[mojoreef]

Well maybe I can go a little deeper. Heres an idea for ya, found it etched on a honey bucket at work .
Sulfide oxidize immediatly in the presence of oxygen, now thier are a bunch of microbes that will use it as energy. now these same microbes use nitrate as electron acceptors, but your bi product of all of this is sulfate. Now sulfate can not be reduced until it reacts with ATP, once it has done that you get ...damm ...cant remember...but a real long chemical name some type of phosphate ( I will break open the books). From here it gets reduced. Now in the reduction (if its assimilative) it can be incorporated into organic compounds (mostly ammino acids).
See I see the closed system as kind of a hyper zone when compared to the wild in regards to this. More pollution, less flow, less dillution so on and so on.


Mike

 

[Cosmic]

We don't see these anaerobic sulfide reduction areas near the surface in reef tanks, it must be occuring in either totally anoxic microenvironments or in deep areas where obligatory anaerobes functioin

I don't know if you can go that far Tom...
If you mean the black areas in the sand when you mention "anaerobic sulfide reduction areas", I have seen several of these pockets occur less than 1/2" from the surface in the 2" bed of my nano, leading me to believe they can't be ALL anaerobic in nature. I will admit that most of those dark areas occured when the tank was young, but the fact that they occured so shallow, and in a shallow bed no less should have some merit.

More pollution, less flow, less dillution so on and so on.

Hence the need for regular water changes, which I have Always followed religiously. If it goes in, you're gonna HAVE to take it back out sooner or later. I'm really starting to be of the opinion that any system can be succesful as long as we keep this in mind. Absolutely nothing beats a fresh water change.
(Not to try changing the subject or anything...lol)

Cos

 

[mojoreef]

(Not to try changing the subject or anything...lol)

Ya ya nice try
Water changes are great for dilluting pollution in the water column but I dont see how thier going to touch anything in the Sandbed.


Mike

 

[Bomber]

Not unless you beat the hell out of that sand bed first.

and what's up with all these little blue letters on a gray background, how does someone your age see this crap anyway? Make the damn print larger so someone can see something and they just might post!

and I will not tell Alice to kiss you again.