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DSBs Frustration

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MINIATUS

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Joined
Sep 21, 2003
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337
Mojo, or anyone
Redoing my tank over after a major salt problem, anyway I have 4 inchs of SD sitting in buckets waiting to decide weather to go with 1-1.5 inches or 4-6 inch full blown sand bed. I've done nothing but read, read read on this topic,and the answers are never the same. Now I'm hearing that DSBs are crashing after a few years. Any truth to this. Mojo I think suggest to take it out at one point. Mike if your here bring me up todate, on some ideas or facts that will help me decide.Your honest opinions in this matter would be of great help to someone thats a little dense at times.LOL

MINIATUS :?:
 

OnTheReef

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Oct 1, 2003
Messages
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Location
Santa Cruz, CA
Re: DSBs frustration

Well, I'll bite. :eek: Fact: unless given some kind of regular stimulation, your sand bed will clog with detritus, compact and start to rot -- it may take awhile, but it's just a matter of time. What's worse, it will almost certainly do so anaerobically. There are several readily available options for keeping the sand bed fluffed up and alive, any or all of which you may choose to use:
1) reverse flow undergravel filter
2) plenum
3) siphon vacuum (1x week)
4) sand processing critters (sand-sifting starfish, lawnmower blenny, goby, sand-sifting sea cucumber etc.)

I have a 1.5" sandbed which contains two sand-sifting starfish and a sand-sifting sea cucmuber. I siphon vacuum the substrate once a week, making sure to pull the sand up into the tube so it's thoroughly agitated. So far, so good. No gas pockets, no black elemental sulfer deposits, etc.

My second and smaller reef tank has a 2.5-3.0" sand bed, which only gets vaciuumed. It's a stretch calling this a reef, since it only has fish, live rock, a flame scallop and an anemone, but this sand bed is also very healthy.

I realize this doesn't speak directly to the 4-6" DSB, but so many people, the folks at my favorite shop included, swear by the above parameters, that I decided to follow their advice. It's working well for me, so no DSB for me at this time.
 

MtnDewMan

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Jun 27, 2003
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Mukilteo, WA
I recently removed my DSB due to a crash of the bed. It stopped working and ended up being a detritus sink instead of processing the detritus. The sulfide zone was only 1/2" from the surface when it should have been 3" from the surface. Basically rendering the bed useless after time.

I personally would lean to a tank without a DSB if you are starting it up from scratch.
 

jesshimom

I have no fish.
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Oct 9, 2003
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Lovely Lynnwood
Another question

I'm with Miniatus it's very confusing. If you are vacuuming your substrate; what about under the rocks? Do you move them? Ok I can't imagine you'd move them every time, but every so often? and looking at the pictures, the tank floors are usually filled up with stuff, you just vac around or move stuff?
 

OnTheReef

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Joined
Oct 1, 2003
Messages
72
Location
Santa Cruz, CA
Re: vacuuming (was DSBs frustrations)

No, I don't disassemble my reef when vacuuming. :) I do have a few pieces which are not part of the structure that I move when I vacuum. Other than that, I just reach everywhere I can. I have this really cool 3/4" extendable vacuum that I can get almost everywhere in the tank. They carry them at The Fish Store, but I haven't seen them anywhere else. The sand-sifting stars and sand-sifting sea cucumber are really efficient -- there's not much to do in the areas they filter.
 

mojoreef

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MIN!!!!!! ok buddy I will give you the short and skinny on sand substriaghts. I havent read he above comments so if I am repeating some one, sorry.
Ok The DSB. A dsb is set up as a denitrifier, it is based on bacteria not bugs, the bugs stir the bed but the bacteria does the work. From nitrification (ammonia to nitrite to nitrate) in the areboic zone (about 1 inch level. Then denitrification (nitrate to nitrogen gas) in the anoxic zone (transistion zone between areobic and anerobic) . the anoxic zone is about a 1/2 deep and is just below the areobic zone. OK from here on down is the anerobic zone (no oxygen) and contains only bacteria that reduce sufide, methagenes and so on. Thier biproducts (waste) is toxic and does nothing for the system, could actually kill the tank. so that is how it is made up. So if you have a 6 inch bed 1 1/2 to 2 inches do you SOME good the rest is dangerious. So bottom line here is if it isnt nitrogenious waste it sinks, if it sinks and you tank has a botton the bed will fill over time and become all anerobic.
Ok another problem with sand substarights (biggest problem for us) is Phosphates. We can only test for inorganic phosphate which is tiny in percentage to the organic phosphate in our tank. Now argonite sand is a super sponge of phosphate. With critter activity the phosphate laidened sand is dropped down to the lower ph waters of the dsb, this releases the phosphates and it is taken up by algaes (blooms of cyano and hair and so on). the algae grow and uses up the phosphate, then it begins to die off as the nutrient is used up, this decaying vegitaion creates a bloom of bacteria that begins to reduce it. As it reduces the algae in binds the phosphate to itself. Then the food runs out for the bacteria, and it begins to die off, and thus releases the phosphate back into the water, and thalgae bloom begins all over again. A continious cycle. Now by feeding our tanks and adding additives we continue to add phosphate to the system. so the blooms (bacterial and algae) become larger and more often. with the large bacteriaal blooms the respiration of o2 is huge and will in itself will create anerobic zones and thus greatly age the bed.
So the good about a DSb is that it process nitrogenious waste.The bad is that is all that it does so everything that is not nitrogen based sinks and fills the bed. the phosphate problem is huge and thats why you always here about folks with the algae blooms.
Min we are always trying to export waste from our tank but with the sand bed we store it...doesnt make sence to me. If you setup a simple maintence schedule of vacuuming out a thin substraight or Bare bottom the waste is gone and does not have to be processed...nada...zippo...gone.
Min if you want my opinion, get rid of the sand and replace it with a bit of maintenance and you dont have to deal with it later. Remember you have LR in the tank and it does the exact same thing but it doesnt sink. it actually sheds it. If you dont like the look of bare bottom the put a little bit of CC down to cover the exposed areas. 2 inches is going to do the same thing with phosphates and will sink what it doesnt process, remote beds will starve and die out infuana wise, thus making it useless. Unless you feed it , which kinda defeates the porpose.

take care bro.

Mike
 

Doug1

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Aug 1, 2003
Messages
249
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Southern Oregon
Theres a lotta truth to whats been said, but I think that one problem with DSB is that alot of people just through in the southdown or whatever and throw raw rock in on top of it expecting it to perform a miracle. They can be successful for quite a while if you have enough scavengers to process the waste, tho its not complete nor infinite. They are more suited to a lagoonal type tank than a high energy SPS tank, and other export systems in place will help to. Having said that minimal substrate and water flows that keep most detritous in suspension, as well as a huge skimmer and other export methods will avoid the toxic buildup, tho I am still not convinced that every DSB is a time bomb waiting to go off.
I like my fish poop , but I could be talked into giving it up ;)
 

mojoreef

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They can be successful for quite a while if you have enough scavengers to process the waste
See the scavengers dont process anything Doug. through bacterial reduction you can process nitrogenious waste to nitrogen gas, then the gas is offed into the atmostphere. but thats it, nothing more ever gets exported. it all stays. see you cant maintain a dsb, you cant clean it, if you do you risk releasing toxins, you cant recreate the flow in the wild that would airate and pull the detritus out of the sand (as happens in the wild) for fear of looking at a milkshake. you will never be able to keep the ammount of infuana in the bed because of recruitment. the strongest most resilient critters will survive all others will perish over time ( the worm lives). so you must replenish the infuana constantly to just keep up to ineffective.Then what do you do with the phosphate???? you cant have the flow needed to keep the corals healthy, you are controled in the inhabitants you can keep (basically nothing that will eats your precious bugs).And you do all this for a filtration system that only processes one type of base (nitrogen). is finite and will have to be replaced. and is a phosphate sponge.
Give me my syphon vac and I will be a happy guy.

Mike
 

Playa

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Joined
Aug 11, 2003
Messages
71
Hey Fellows,

I had a thread going on RC on the DSB issue. This is a wonderful thread and relates to my concerns as well. I am setting a new 180 and after a conversation with Mike on the phone the other day he left a seed planted and now I am on the move.

I posted on RC a link to this thread.

Nice going!
 

Doug1

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Aug 1, 2003
Messages
249
Location
Southern Oregon
" See the scavengers dont process anything Doug. through bacterial reduction you can process nitrogenious waste to nitrogen gas, then the gas is offed into the atmostphere. but thats it, nothing more ever gets exported. it all stays" Oh contrare mon frere, you somewhat contradicted your own self there :) The Nitrogenous waste(ammonia, etc) are reduced by bacterial action or removed by skimming, etc. Scavengers , be they hermits, snails, brittle stars, bristleworms etc, eat left overs and absorb what they can, expelling the waste, which is in turn eaten by something farther down the food chain. Examples cited use the figures 8 layers of consumption, from primary grazers all the way down to bacteria. The bacteria that process N arent the only ones, there are others that consume sulphides, etc, freeing organic carbon that may be fixed by corals in that dam complicated calcium./carbonate equasion that still baffles me. Phosphates can be uptaken in macro algae, tho I won't pretend to know whether its organic or inorganic forms.
My point is that scavengers and bacteria are not the end all, be all that they have been hyped, but to say that they don't process nothing is a Ronism :D Notice I have maintained that they can work for a finite length of time, if certain params are established and that the aquariust understands the dynamics of a DSB, the pros as well as the cons and uses it along with other export methods,as well as watching the input of nutrients.
6" of new SD in a DSB, heavily fed and no back up is a disaster in the making but...............................
 

aquariumdebacle

electrolyte addict
Joined
Jul 4, 2003
Messages
613
Location
Seattle
dsb ecosystem

I must agree with the previous. You must look at the systems as ecosytems; any one aspect must be taken with the whole group. These are mostly closed systems. To borrow a phrase from the computer industry gigo. The energy that you put in to a system (food and electricity primarily) must be compensated for. The bacteria being the lowest common denominator will utimately compensate, do want cultivate just bacteria? The more acurate way to view these diverse situations is to take an overall ecological perspective.

The way I perceive a stony coral tank is like a barren desert with virtually no nutrients and consequently, no life (or very little especially vertabrates.)

The way I perceive a deep sand bed is much more like a tropical rain forest. The nutrients are bound up in living tissue. Remove the canopy and you are left with a desert (clear-stripping.) The diversity of a rain forest is the key to it's ability to keep nutrients bound up and the export is in the form of heat through the respiration of animals.

This may not be the "ideal enviroment" for stony corals, but I believe that it allows for the most diverse group of organisms. None of this means that regular maintence and effort should be eliminated. It just comes back to what you want to accomplish.

I will keep you posted on my trickle filter and deep sand bed combination!
 

mojoreef

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Hey DOugie great to have ya join the conversation.
Oh contrare mon frere, you somewhat contradicted your own self there The Nitrogenous waste(ammonia, etc) are reduced by bacterial action or removed by skimming, etc. Scavengers , be they hermits, snails, brittle stars, bristleworms etc, eat left overs and absorb what they can, expelling the waste, which is in turn eaten by something farther down the food chain. Examples cited use the figures 8 layers of consumption, from primary grazers all the way down to bacteria.
I am not sure I understand you bro, I did say that it will process nitrogen based waste. As per the critters such as crab/snails/worms/ and things like that they dont export anything. They eat through the detritus absorbing 10% of thier intake, pooping out the balance, unless u toss them they hold what they ingest until they die or are eaten themselves. Bacteria on the other hand in the areobic and anerobic zone process nitrogenious waste to gas (nitrogen). U can have 800 layers of consumption, but if its not exported its still thier.
The bacteria that process N arent the only ones, there are others that consume sulphides, etc, freeing organic carbon that may be fixed by corals in that dam complicated calcium./carbonate equasion that still baffles me.
your are correct again Doug thier are many differing type of bacteria in the bed. The sulfur reducing bacteria you refer to have a biproduct of sulfide, which is not what we want for our tanks.Sulfide reduction is limited by carbon as most sulfate isdissimilative and thus requires a source of electrons.
When u are taking about carbon cycle you are talking about bacteria that are called methagenes and that are a little further down in the bacterial ecosystem. Sufur reducing bacteria are actually a competitor of the methagen reducing bacteria. The SRB' compete for hydrogen much better. Now even thier was anything in the way of carbon produced in the bed it would be below the sulfide zone and would not be available to the tank.
Yes phosphate is taken up by algae, and thus bacteria as I have mentioned in my above post. But the phosphate will cycle in your sand bed, and personally i dont like the look of cyano or hair algae coming out of my bed, but that is a personal opinion.
So my friend I still say that scavengers dont do anything but sink nutrients (unless they are exported) and that they only desirable bacterial action is that of the nitrogen cycle.

mike
 

mojoreef

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This may not be the "ideal enviroment" for stony corals, but I believe that it allows for the most diverse group of organisms. None of this means that regular maintence and effort should be eliminated. It just comes back to what you want to accomplish.
aquariumdebacle its not the enviroment for almost all reefs. If you wish to keep a lagoonal tank with corals that are nutrient resistant or use nutrients then maybe this system will work for you. But it will not change the one main aspect. A DSB has a bottom unlike nature and does not get sweeped clen like happens in nature with storms/wave action/ tidal flows, it just stays in our tank collecting.
I am not saying to not use a DSB, everyone can do what they will. But to many folks dont understand thier limitations and thier pitfalls. Alot of folks think its dump and go. Not even close my friends, u basically need to do everything a person with out a DSB does, or it will die.


Mike
 

ReefShack

sps junkie
Joined
Sep 2, 2003
Messages
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Snohomish, WA
I realize that we are talking about a DSB in the display but, what if it was moved outside of the display tank and into a remote vessle? Without the critters depositing solid waste into the DSB, it seems to me you would be able to keep it going longer. What would be the pros and cons of doing it this way?
 

mojoreef

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Reefshack the whole concept of a DSB is to take care of that solid waste. If your protecting the sand from it, it kinda doesnt make sence to have it in the first place???
Maybe I am not understanding you??

Mike
 

Scooterman

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Oct 30, 2003
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Louisiana
I don't think anyone will ever convince Mike to use a DSB, LOL!

In about 12 months of reading about DSB's, a few months ago I removed mine.

Results!

Way less algae problems!
:eek: :eek: :shock:
Tank looks way better, without all that sand.
I can now crank up the current and blow water like crazy with no problems, which in itself makes a huge difference!

You want clean water, replace it while vacuuming!
 

aquariumdebacle

electrolyte addict
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vacuuming

What I think needs to be understood is that a DSB is a specific ecosystem. There are many different types and it is best to look at it as one of the many varied types. Lagoonal (or neglected) tanks are a type, so are high energy reefs, as well as fish only and species specific. If you want creatures that live in the sand, a DSB is an absolute must. If you're looking to keep other types many options remain open. Figure out what you want to keep, and only then design a system to fit their specific needs.
 

Katchupoy

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Jul 9, 2003
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Kent 98031
I've been using barebottom for several years. Then I tried to add sand hoping for a DSB system for about 6 months. Didn't like it because of so many reasons. Then I went back to barebottom.

In my experience, I prefer barebottom because you can design your flow in such away that it will blow all detritus in one corner/area wherein you can vacuum it later on for collection. You can do this when you're doing water changes and in this way you dont cloud the water.

With already so many factors out there to make your tank/corals not perform, I dont want to add more by adding DSB (the reason for this is because I dont know anything about it).

Am not saying its bad but I believe this is for the people with more experience in this field.
 

mojoreef

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I think the biggist problems with DSB's is that they are misunderstood. Most people think of them as a sourse of filtration. A DSB is a recycling system t p using complex bacterial cycles. Nitrogen based products will however will get exported, as a part of the nitrogen the nitrogen cycle is to turn nitrates in to nitrogen gass (which is off gassed). But all other cycles are do not have an export system. So if it isnt nitrogen based it joins and endless cycle in the DSB. The biggest problem to that is that a DSB cannot be cleaned out so through accumulation it is finite.


Mike
 
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