DSB with MUD underneath- problematic for normal DSB methodology?

[Newreeflady]

Before I ask, I should tell you that I'm looking to keep the following animals:

Plants:
Seagrasses
Macroalgae

Inverts:
BTAs (green & red)
Clams (maxima)

Fish:
Ocellaris pair
Dwarf Angel
Yellow Coris Wrasse
Pajama Cardinals

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Tech specs: Flow 2 x Eheim 1262 (one sump pump, one CL), skimmer yes, lighting 250w halide, calcium via kalk

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On with it then

I have been told that it may be good to have an underlayering of mud below the dsb, for (,at least in areas where I intend to keep,) the seagrasses. This sort of conflicts with the advice of keeping the substrate in a non-too-spread size range for a functional dsb (ie, all sugar fine) although it is a bit in the opposite direction (I think this advice is most often offered to those wanting to mix in cc.)

So, does anyone see a problem with keeping mud underneath aragonite- an inch maybe of the 5 total inches of substrate planned for the tank.

This is NOT a DSB v SSB v BB arguing thread- if you don't have an answer about this particular question of mud underneat the DSB, then simply don't reply- that easy

Thanks!
Angela

 

[elegance coral]

The only problem I see is trying to keep phosphate low enough to not impede the clams growth while keeping it high enough to fuel the sea grass growth. It may be challenging to keep both healthy.

 

[100%hydrophylic]

i didnt think the mud contributed to high phosphates? some people swear by putting the mud products in their fuge in any tanks they have, including ones with clams.

i think if you get past the downsides (if you see anything as a downside) of the mud, it would be perfectly fine to have it as a layer of the DSB. if you were going to have the mud as a part of your system anyway, then i dont think it would hurt to have it in the tank rather than the fuge.

 

[elegance coral]

i didnt think the mud contributed to high phosphates? some people swear by putting the mud products in their fuge in any tanks they have, including ones with clams.

http://www.reefs.org/library/article/mm_analysis.html

4,621 ppm po4.

 

[Newreeflady]

Well, as I understand it phosphate isn't a real concern. I actually had two croceas develop pinched mantle within 24 hours of adding Phosban to the tank. I changed water and ran carbon like mad and it went away in a couple of weeks. This was my first hint that phosphates are not always a bad thing!

After your comment, though, I was inspired to take a look to see if I could find any info about phosphates and tridacnids. I did find a link to an article that found that increased phosphates (albeit for 2-3hr a day) did not adversely affect maxima:
http://www.springerlink.com/content/09gewj69kfj7wwk4/

I also found an RC thread where TMZ posted some info:
http://www.reefcentral.com/forums/showthread.php?t=1474839&page=4
basically, I'm not the only person who has seen this problem with phosphate reduction for clams. Of course, it's hard to know if it is a reduction rate problem, or if it is an actual deficiency problem. Either way, it sounds like they are more opposed to the removal of phosphates than the actual phosphates themselves.

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Now, not sure if phosphates will be a problem for the the BTAs...... :/ ?

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I had no idea the mud was so rich. That's good, because it's very expensive. Any thoughts on compaction issues?

Thanks!
Angela

 

[ruprecht]

I have no personal experience with seagrasses, but I am relatively confidant that your DSB will not function properly with seagrass in it. Generally, seagrass rhizomes (roots) produce oxygen, thus having elevated oxygens levels in the deepest part of your DSB would not be beneficial to its function.

 

[spamreefnew]

i did the mud thing about 6 months ago,it seemed to work ok but when you do ANYTHING to your sump/fuge you ALWAYS end up disturbing the mud somehow and it clouds your tank for days. but maybe with rooting plants it will work out for you?

 

[Newreeflady]

ruprecht, that certainly requires more research on my part! Thank you for bringing it up- I'm not terribly familiar with seagrasses myself, but thought they might be a neat addition.

spam, Well, considering it'd be covered in 4" of aragonite, and that one shouldn't disturb a dsb, I don't think we'd have the same issue.

-A

 

[3D-Reef]

Angela,the only problem I see with Your stocking list is the Dwarf Angel.Depending on which one,it might eat the grass You want to keep.

elegance coral "The only problem I see is trying to keep phosphate low enough to not impede the clams growth while keeping it high enough to fuel the sea grass growth. It may be challenging to keep both healthy. 4,621 ppm po4."

How many ppm/grains of sand,of CaC03,does it take to bind 1ppm of phosphate?With 4:1 ratio of CaC03 too mud (DW),wouldn't the DIP bind to the CaC03 before it ever got to the water column?Not to mention microbial and seagrass up-take of P,the rate of demineralization of the substrate or the slow flux rates in pore water. Without knowing these variables that factor into the equation,then 4621ppm P04,is just a number.IMO Beside the grass the OP is wanting to keep,star grass and shoal grass,are early colonizers,thus they don't need the high nutrient demands that a climax sp. would need.ie Thassodendron,Posidonia,or Thalassia

I have no personal experience with seagrasses, but I am relatively confidant that your DSB will not function properly with seagrass in it. Generally, seagrass rhizomes (roots) produce oxygen, thus having elevated oxygens levels in the deepest part of your DSB would not be beneficial to its function.

Seagrass sediments are far more complex than that of common DSB's.While it's true that rhizomes and roots will leach photosynthetic derived 02,it is limited to an oxic zone of 80 µm in C.rotundata roots during daylight hours and 50µm at night .Pedersen et al (1998) So the effect would be limited to those areas which are quite small in scale compared too the overall DSB footprint.
From the book Seagrasses(2006);"Since denitrification requires a close coupling of aerobic and anaerobic processes,it would seem that the seagrass rhizosphere,where oxic microlayers caused by oxgen release from the roots intermix with hypoxic or anoxic zone (Kuo and den Hartog),constitutes an optimal environment where it can take place.(Hemminga and Daurte,2000).
Indeed,some evidence indicates that denitrinfication is higher in seagrass beds than in neighboring bare sediments (e.g. Caffrey and Kemp,1990;Miyajima et al.,2001)" But that depends on which grass is being studied.

 

[ruprecht]

Seagrass sediments are far more complex than that of common DSB's.While it's true that rhizomes and roots will leach photosynthetic derived 02,it is limited to an oxic zone of 80 µm in C.rotundata roots during daylight hours and 50µm at night .Pedersen et al (1998) So the effect would be limited to those areas which are quite small in scale compared too the overall DSB footprint.

From the book Seagrasses(2006);"Since denitrification requires a close coupling of aerobic and anaerobic processes,it would seem that the seagrass rhizosphere,where oxic microlayers caused by oxgen release from the roots intermix with hypoxic or anoxic zone (Kuo and den Hartog),constitutes an optimal environment where it can take place.(Hemminga and Daurte,2000).
Indeed,some evidence indicates that denitrinfication is higher in seagrass beds than in neighboring bare sediments (e.g. Caffrey and Kemp,1990;Miyajima et al.,2001)" But that depends on which grass is being studied.

Good reads. I'll buy it, but Seagrass Ecology also goes on to say that seagrass beds tend to reduce flow and increase detrital deposition.

These two things tend not be beneficial to a DSB.

 

[3D-Reef]

Good reads. I'll buy it, but Seagrass Ecology also goes on to say that seagrass beds tend to reduce flow and increase detrital deposition.

These two things tend not be beneficial to a DSB.

Oh great,now there's another $120.00-$150.00 I'm going to be out of.j/k No really,Thanks for the good link!:thumbsup:

FWIW,To answer Your question in full it will take more typing than what I can post tonight.It may take a couple of nights.So please be patient!

Your right,they do reduce flow and have effects on particle deposition,which, in a normal DSB you wouldn't want too happen.
Since we're in the advanced forum,let's look at what most would consider a DSB too be and how it works.Then compare that,too how seagrass sediments work.

I think most of us can agree,for the most part,that a DSB is made up of ~4"-6" of aragonite sand (CaC03).Caracteristically it has vast amounts of surface area beneficial to N-cycling.Which,most people have a basic understanding of nitrification-denitrification,so I won't go into that.But,basically,the end product of which is N2 that degasses up through the water column.So N goes in,in one form and comes out in another form.No real build up too speak of if it's set up properly.
On the other hand,P is chemically bound too the CaC03 substrate,and there is only four ways,that I can think of,that can reduce the level of P in the system.The first way would be too physically remove the sand.The second way P could be released,from the sand,is by bacteria.The third way is by plant up take,but,at a cost to the plant.The forth way would be equalization.ie if the water column has less of P in it and an excess in the sediments,the P at some point will leach out and then aquarist can imploy some type of removal like GFO,algae,ect.
Stiring/syphoning,from the begining,is one way too prolong the DSB's life,but what does it actually remove if N doesn't build up and P is almost irreversibly bound to the sand? DOC is the only conclusion that I can come up with.So the "trick" to a DSB's well being,is,too limit the amount of DOC's.
In summary,the basic DSB has only three things going on,N-cycling,P-binding,and C build up.

 

[ruprecht]

In summary,the basic DSB has only three things going on,N-cycling,P-binding,and C build up.

It is not my intention to hijack this thread, so I'll just PM 3D.

But P and C cycle too.

 

[Newreeflady]

I think it's a little fuzzy so feel free to debate it here. We can discuss DSB theory as it is relevant in the context of adding mud to the system- how can we know if the later is OK unless we well understand the former?

cheers.

 

[3D-Reef]

But P and C cycle too.

Well...yes and no.Yes..But,it's more on a microbial scale,and is small in comparison too the over all (macro) scope of things,at least in the first few years,IMO.This is why you see post saying that for the first 3-4 years they have no problems with a DSB.That's because almost all of it (P) is binding to the substrate.
I didn't include this in the above post so as to not confuse anyone into thinking that P & C cycling on the macro scale is acceptable.Inevitably some nubie will read this and will get the wrong impression.I wasn't going to get into this until later,but since it's been brought up...

No.. because you don't want P & C cycling on a macro scale.If a DSB is left too build up so much POM/DOM as to start the cycling processes of C & P on a macro scale,then a R&R is in order.I'm a mechanic by trade:spin1::hammer:,so that should read;remove and/or replace,not rest and relaxation.:thumbsup:
The end result of P-cycling on the macro scale is ATP (adenosine triphosphate),a high energy compound used by both plants and bacteria.aka. HA,cyano,possibly dino's,and maybe diatoms.I'm not sure on the last two,so don't quote Me on that.
This link is a cartoon of ATP in action.http://vcell.ndsu.nodak.edu/animations/atpgradient/movie-flash.htm

Now with C-cycling on the macro scale,the reason you don't want this to start is;accumulated DOC's in the lower regions stimulates the reduction of sulfates.As DOC builds up,the bacteria use the carbon for energy,and use the sulfate (S04) as an oxygen supply.The end result is H2S,a highly toxic gas.Toxic for grass,inverts,fish,pretty much everything alive including you and Me.But not too worry,it would smell to High Heaven before it got to that level.
Which is why VSV dosing doesn't work very well with older DSB's,IMO,and people are sometimes told to remove the DSB before dosing.The reason being when glucose is added to an already organic inriched substrate the sulfide production is greatly increased (~ten fold) and causing the pH of the sustrate to drop from ~7.5 too below 6.5.This causes the toxic gas H2S to increase as well,~3 fold.The net results in a ten fold increase of sulfide,and a three fold increase of the gas,is an increase of thirty fold of the most toxic fraction of the sediment sulfide pool.*

* Influence of Sediment Sulfide on the Structure of Florida Seagrass Communities Carlson,Yabro,and others, ~2001(?)

 

[elegance coral]

elegance coral "The only problem I see is trying to keep phosphate low enough to not impede the clams growth while keeping it high enough to fuel the sea grass growth. It may be challenging to keep both healthy. 4,621 ppm po4."

How many ppm/grains of sand,of CaC03,does it take to bind 1ppm of phosphate?

I have no idea.:lmao:

With 4:1 ratio of CaC03 too mud (DW),wouldn't the DIP bind to the CaC03 before it ever got to the water column?

When phosphate binds to calcium carbonate of sand, its not the end of the story. There's a cycle of phosphate binding to, and being liberated from, calcium carbonate. Even if it does bind to calcium carbonate, that doesn't mean it won't reach the water column.

Not to mention microbial and seagrass up-take of P,the rate of demineralization of the substrate or the slow flux rates in pore water.

You are not going to create an impenetrable force field over the sand that keeps phosphate from escaping. When you add phosphate to the system, it is always in the system until it is removed. It doesn't matter if microbes barrow some for a short time, or if some is temporarily bound to calcium carbonate. It will just continue to cycle through the system.

Without knowing these variables that factor into the equation,then 4621ppm P04,is just a number.

Just knowing what "Miracle Mud" is, tells us that it's loaded with phosphate. We don't really need a number to tell us this. Although the number really does bring it home. All living tissue contains phosphate. When it dies and decomposes, it releases this phosphate into the environment. When the suppliers of MM go deep under the ocean and collect sediments, we know it's loaded with organic matter. Then they dry it out on land, which kills the living matter in the sand. When we place this organic matter into our warm, wet aquariums, it begins to decompose. You don't have to be a biologist or chemist to know that this is going to release vast quantities of phosphate. We utilize this process every time we put compost into a flower bed.

 

[elegance coral]

Well, as I understand it phosphate isn't a real concern. I actually had two croceas develop pinched mantle within 24 hours of adding Phosban to the tank. I changed water and ran carbon like mad and it went away in a couple of weeks. This was my first hint that phosphates are not always a bad thing!

Phosphate inhibits calcification. This is a fact we can't get away from. It's questionable as to how much phosphate a clam can withstand before an obvious decline in calcification occurs. All I know is that at some point, elevated phosphate levels can reduce the clams ability to lay down new calcium for its shell.

There is a very intament relationship between the clam and its zooxanthellae. Zooxanthellae growth and reproduction is drastically influenced by the availability of phosphate. The clam is constantly adjusting the population of zooxanthellae within its tissues to keep it within a healthy range. When there is a sudden and drastic change in phosphate concentrations, it can lead to a sudden and drastic change in the zooxanthellae population within the clam. This can throw the population out of the healthy range faster than the clam can react to it. If you have a given population of zooxanthellae within the clam, and you rapidly reduce the phosphate that's available to them, by installing a phosphate reactor, the population can experience a rapid die off. As you can imagine, having a large number of organisms die within the tissues of the clam, may not be very good for it. Given time (maybe two weeks in your case) the clam may be able to make the appropriate adjustments and the zooxanthellae population can return to a healthy level. Rapid changes in nutrient levels like phosphate can lead to rapid changes in zooxanthellae populations that cause problems for coral, anemones, clams, and other critters that share this symbiotic relationship. In these cases, it's not so much the concentration of phosphate that causes the problem. It's the rapid change in phosphate concentrations that causes the problem.


Just for the record. I never said you couldn't keep sea grass and clams in the same system. I just said it may be challenging to provide optimum conditions for both organisms. We do challenging things in this hobby all the time.

 

[ruprecht]

No.. because you don't want P & C cycling on a macro scale.

Then how are things supposed to grow? Without DOC/P there would be no growth.

Several studies have shown that growth on reefs is phosphorus limited, and that any phosphorus 'trapped' in sediments acts as a local benthic nutrient source .

A possible reason that DSB 'work' for a few years before people begin 'having problems' is that they over reach the carrying capacity of their biological system and excess nutrients begin to build up.

As for sulfate, it is not a problem in a healthy DSB because the bottom sediments are not devoid of oxygen.

 

[3D-Reef]

When phosphate binds to calcium carbonate of sand, its not the end of the story. There's a cycle of phosphate binding to, and being liberated from, calcium carbonate. Even if it does bind to calcium carbonate, that doesn't mean it won't reach the water column.
You are not going to create an impenetrable force field over the sand that keeps phosphate from escaping. When you add phosphate to the system, it is always in the system until it is removed. It doesn't matter if microbes barrow some for a short time, or if some is temporarily bound to calcium carbonate. It will just continue to cycle through the system.
Just knowing what "Miracle Mud" is, tells us that it's loaded with phosphate. We don't really need a number to tell us this. Although the number really does bring it home. All living tissue contains phosphate. When it dies and decomposes, it releases this phosphate into the environment. When the suppliers of MM go deep under the ocean and collect sediments, we know it's loaded with organic matter. Then they dry it out on land, which kills the living matter in the sand. When we place this organic matter into our warm, wet aquariums, it begins to decompose. You don't have to be a biologist or chemist to know that this is going to release vast quantities of phosphate. We utilize this process every time we put compost into a flower bed.

I agree whole heartedly,and the amount of mud that I recomended in this thread,http://reefcentral.com/forums/showthread.php?t=1846001 is just a small amount in the area of the grass to be planted,in order to help establish not only those microbes that cycle P,but also to establish a grass bed in a realitive short amount of time.(Also do too time constrainsts of the OP.)
So any P making to the water column,IMO,would be at a minimum,and could be filtered out out if necessary (GFO,lanthanum Cl).With such a small amount of P being releasted,compared to the amount of sand,I don't see it as a problem to a clam that probably came from a lagoonal setting to begin with.
I pointed out in the other thread that seagrasses can servive on less nutrients than what you might think.Do to the cycling-recycling of C,N,& P.Although DSB's support a large amount of these infauna,seagrasses support a higher bio-load of those microbes in the substrate do too the photosynthetic derived 02 and the DOC given off by the rihzomes & roots.

Let me give you My take on DSB's,where too Me they fall into different categories;
1) DSB that is syphoned on a regular basis.IMO it will last the longest over time,causing the least amount of problems.
2) DSB that is left too only the fauna/infauna for for all cycling.ie no sturring/syphoning IMO,this has more diversity than #1,but will only last for 4-6 years do to the eventual build up DOM.
3)A SeaGrass DSB (SGDSB) IMO it is just as #2,no better and no worse,even though it supports an even higher diversity of infauna.

 

[3D-Reef]

Then how are things supposed to grow? Without DOC/P there would be no growth.

Several studies have shown that growth on reefs is phosphorus limited, and that any phosphorus 'trapped' in sediments acts as a local benthic nutrient source .

In most tanks there is usually more DOC/P than what is on a nutrient rich reef,let alone one that's limited.I don't think that limitation of DOC/P is the case with DSB's.

A possible reason that DSB 'work' for a few years before people begin 'having problems' is that they over reach the carrying capacity of their biological system and excess nutrients begin to build up.

IMO that's exactly what happens over time and usually it takes 4-6 years.IMO

As for sulfate, it is not a problem in a healthy DSB because the bottom sediments are not devoid of oxygen.

That's what you want in a healthy DSB,and that is the way it is for most tanks under 3 years,but over time,if DOC's/P are not somehow removed,it will eventually cause the anoxic conditions in the lower levels thus starting sulfate reduction cycle.It's the excess,on a macro scale,of DOC that starts the S-cycle.
On the micro scale,this is what you want with plants,so they have the nutrients they need.The H2S producing bacteria use 02 from the S04 and use C,N,or P from the organic matter,releasing the unused portion of C,N,or P to the plants.But the S-cycle is limited because they (the rihzomes) leach off 02 reoxidizing the toxic sulfide too non-toxic sulfate.This 02 also allows for more microbial activity,thus a higher nitrification-denitrification level.

 

[3D-Reef]

Just for the record. I never said you couldn't keep sea grass and clams in the same system. I just said it may be challenging to provide optimum conditions for both organisms. We do challenging things in this hobby all the time.

Point well taken!:thumbsup: