Deep Sand Bed (DSB) - The unpopular opinion

[Dolphins18]

Hello,

I realize this is my first post on this forum but I wanted to shed some light on my experience with DSB's. I've been a part of other forums for 10+ years but have recently been attracted to this site, and the amount of traffic it receives.

I am no scientist by any means, but I will let you guys know my thoughts on running a DSB in a fuge. I have had a a DSB in my fuge for about 15 years, feeding a 25 year old display that has crushed coral as its substrate.

My sand bed is about 4-5" deep in the fuge. It is full of black metal deposits. I accidentally dropped a rock that had previously been buried in the sand for the last 5 years and it made a huge brown mess in both the tank and the fuge. Attached is a picture showing the amount of black metal deposits in the sand. Typically, these are associated with a chemical known as Hydrogen Sulfide (H2S), this is an incredibly toxic gas that when released can cause major harm to all living creatures, including humans. Some people in the past have determined this has crashed their entire tank. (Note: I had not stirred the sand once since it was put in)

I was looking for something in the DSB that ripped a large clown to pieces. I did not find it, but I dropped a rock and made a huge mess. Naturally, I was pretty worried after seeing how much of a mess I made. The display is stocked full of fish, corals, and various inverts. They did not seem to mind much, and after a stressful night, I woke up to what appeared to be a perfectly normal tank.

With all of this being said, I realize it is possible that H2S may have been released into the tank, though I did not notice much of a smell. The process I used to eliminate it (if there was even any present), was virtually nothing. I made sure the tank was fed a steady supply of oxygen through water agitation, I continued to run the same 2 month old GFO in a reactor , and left the lights on a bit longer than usual to expedite the elimination of H2S (again, if it was even present). I skim all the time, and do water changes on this tank probably every 2 months or so. (I would not suggest waiting 2 months to change water on a young tank)

I see a lot of different theories on Deep Sand Beds, and IMO, I think they are an excellent breeding ground for pods, and seem to offer some denitrification properties. I don't think anyone should knock it until they try it. I have never tried a bare bottom tank, but I have run plenty of 2" sand beds, and while I did not have too many major problems, I did notice much more nuisance algae growth in the shallow sand bed tanks.

This is just my 2 cents, I am by no means saying that it can't be a tank killer, I am simply stating that in my experience it has been very beneficial.

For reference this is a 90g display with a 30g sump.

Id love to hear someone's thoughts who understands the science behind this a bit more.

 

[rusty hannon]

Hello,

I realize this is my first post on this forum but I wanted to shed some light on my experience with DSB's. I've been a part of other forums for 10+ years but have recently been attracted to this site, and the amount of traffic it receives.

I am no scientist by any means, but I will let you guys know my thoughts on running a DSB in a fuge. I have had a a DSB in my fuge for about 15 years, feeding a 25 year old display that has crushed coral as its substrate.

My sand bed is about 4-5" deep in the fuge. It is full of black metal deposits. I accidentally dropped a rock that had previously been buried in the sand for the last 5 years and it made a huge brown mess in both the tank and the fuge. Attached is a picture showing the amount of black metal deposits in the sand. Typically, these are associated with a chemical known as Hydrogen Sulfide (H2S), this is an incredibly toxic gas that when released can cause major harm to all living creatures, including humans. Some people in the past have determined this has crashed their entire tank. (Note: I had not stirred the sand once since it was put in)

I was looking for something in the DSB that ripped a large clown to pieces. I did not find it, but I dropped a rock and made a huge mess. Naturally, I was pretty worried after seeing how much of a mess I made. The display is stocked full of fish, corals, and various inverts. They did not seem to mind much, and after a stressful night, I woke up to what appeared to be a perfectly normal tank.

With all of this being said, I realize it is possible that H2S may have been released into the tank, though I did not notice much of a smell. The process I used to eliminate it (if there was even any present), was virtually nothing. I made sure the tank was fed a steady supply of oxygen through water agitation, I continued to run the same 2 month old GFO in a reactor , and left the lights on a bit longer than usual to expedite the elimination of H2S (again, if it was even present). I skim all the time, and do water changes on this tank probably every 2 months or so. (I would not suggest waiting 2 months to change water on a young tank)

I see a lot of different theories on Deep Sand Beds, and IMO, I think they are an excellent breeding ground for pods, and seem to offer some denitrification properties. I don't think anyone should knock it until they try it. I have never tried a bare bottom tank, but I have run plenty of 2" sand beds, and while I did not have too many major problems, I did notice much more nuisance algae growth in the shallow sand bed tanks.

This is just my 2 cents, I am by no means saying that it can't be a tank killer, I am simply stating that in my experience it has been very beneficial.

For reference this is a 90g display with a 30g sump.

Id love to hear someone's thoughts who understands the science behind this a bit more.

Very informative, thank you

 

[Crustaceon]

I ran a 29 gallon with a 6” dsb. It was freakishly stable as far as nitrates and phosphates goes and it drove me nuts because I couldn’t get the same results in my 100g when I tried to go bare bottom. That 29 grew coralline algae and pretty much everything else like crazy. The 100g simply didn’t at that time. Since then, I switched to 55g and added a 3L of seachem matrix which is far more than what they recommend. I’m getting those good results again. Biological filtration is easily-mode.

 

[burgundy]

is 6in the minimum for a good dsb depth?

 

[ReefBeta]

In my opinion, lots of the sentiments of DSB are because of the old time and methods. I don't remember seeing anyone to actually proofed DSB itself crashed tanks. People crash tanks. In the old time, people crash tanks a lot, and people use DSB a lot, and people are not good at separating causation and correlation. The fear of DSB sounds more like stuff people making up from theorycrafting than proven theory.

I think DSB falling out of popularity is really because of the space requirement, and cost of sand. Also it's proven to not essential. Reefkeeping nowadays are more and more trending towards targeting specific problem and specific solution.

 

[Paul B]

I personally have never liked DSBs and used them in small local creature tanks. I even remember when they were invented and espoused by Dr Schmeck.

I believe the science behind them is flawed and they have a definite, short lifespan where they actualy do anything beneficial.
The theory is of course that worms and other creatures will burry down through the sediments, stirring it up so some water can get there. That only happens for a little while as there is no oxygen down there and as was said, probably hydrogen sulfide which is the exact opposite of what we want. Those worms also don't live very long.
I feel after a short while, a DSB may not crash the tank but it will be benign.
Just my opinion of course.

 

[jda]

Most of the venom for sand beds come from a few very loud posters who have never really tried them and have no idea what they are talking about outside of their own minds. Thankfully, they have not posted yet.

I think that Dr. Ron nailed most everything except, 1). I stop at about 3 inches since I don't see the need for 6 since 3 inches will denitrify and keep the same fauna perfectly well, and 2). that the sand beds need cleaned over the years to get the benign detritus out so that the fauna can work the areas again. I vacuum out my sandbeds at about year four doing about 25% every three months over the year timeframe - this allows the oxic and anoxic areas to repopulate before you do more. It is amazing to watch the fauna rush to the freshly vacuumed areas and do their jobs well again.

Since 1992, I have never smelled nor see any h2s in any of my tanks.

Perhaps my most favorite things about sand beds (shallow or deep) is that they have so much life, microbes and microfauna that my fish are many times more healthy. I would not want to be an ich tomont that dropped off of a fish into my sandbed - it is probably dinner in less than an hour.

In short, they are as advertised, but they need work periodically and cannot do their thing indefinitely, like anything in a closed system.

 

[HuduVudu]

Typically, these are associated with a chemical known as Hydrogen Sulfide (H2S), this is an incredibly toxic gas that when released can cause major harm to all living creatures, including humans. Some people in the past have determined this has crashed their entire tank.

H2S is only toxic when you can't smell it. In oil fields they wear badges to ensure they know if they are being exposed.

I run a full on anaerobic digester and have dumped untreated effluent straight into my 20 gallon aquarium with no ill effect. People blame the H2S and what they fail to realize is what conditions are causing the H2S ... those conditions would be anaerobic conditions i.e. absence of oxygen. The absence of oxygen IMO is going to be far more deadly than the H2S.

I have used plenums for a large part of my reefing career. I find them to be an awesome stabilizer and very misunderstood. First you WILL get H2S in any form of anaerobic decomposition. A sufficiently oxygenated tank is more than enough to push the sulfur back to sulfate, and even if some of the H2S escapes it is not going to cause catastrophe as stated above, especially if there is some free iron in the tank.

There are some things that anaerobes won't break down (fats seem to be one) and the break down process produces it's own organic output, which will be used by the aerobic process. This means that yes you will get a nitrate reduction but it is limited. Also to note the bed will not remove phosphate from your system. In the anoxic stage the phosphate may go to elemental phosphorus but when it re-enters the aerobic areas it will quickly be converted back.

DSBs and Plenums rely on diffusion to work. This process creates a lag to their function. Also because of diffusion putting rock work on top of them impedes this from happening effeciently creating channels that slow down the work being done. I find it better to not put these in main display tanks to help avoid this pitfall.

DSBs and Plenums do break down aragonite based beds and will provide calcium and carbonate to the system, but the amount is small (though incredibly steady). My current porites and stylo were grown using a small plenum in my tank. They didn't grow fast but they grew well because of the constant steady input. Also because of this break down and channeling in beds on the bottoms of tanks you can get the blocks of cement effect from that calcium carbonate break down.

The trick to quickly starting these beds is to use full strength salt water to rinse the bed before you put it in and then using gravel vac'ed water from an established tank as the first water into the bed. This shortens the cycle time immensely (to four days in my experience).

My 2 cents.

 

[HuduVudu]

is 6in the minimum for a good dsb depth?

Yes but it must stay at six inches.

 

[HuduVudu]

I believe the science behind them is flawed and they have a definite, short lifespan where they actualy do anything beneficial.

I 100% disagree with this. Anaerobic decomposition has a well proven track record in waste water treatment. The short life span is just complete misinformation. My plenum was five years old when I pulled it and replaced it with it's big brother the anaerobic digester. All of my plenums have never had the dreaded nutrient dump, and I find this to be strange as to why people even think it. I believe the biggest problem with DSBs and Plenums is mechanical and not biological, that is they are put on the bottom of tanks. Please see my previous post for an explanation.

The theory is of course that worms and other creatures will burry down through the sediments, stirring it up so some water can get there.

No the theory is that the dead space will create a diffusion gradient. In fact it is encouraged for the top layer to have screening to keep the burrowing fish and inverts out, to maintain the depth to ensure anaerobic conditions.

That only happens for a little while as there is no oxygen down there and as was said, probably hydrogen sulfide which is the exact opposite of what we want.

This is exactly what is happening inside of your live rock. It is beneficial for denitrification and bio-diversity.

Luv ya Paul ... just wanted to set the record straight.

 

[HuduVudu]

I would not want to be an ich tomont that dropped off of a fish into my sandbed - it is probably dinner in less than an hour.

THIS ... This made me laugh.

 

[Paul B]

I remember when Dr Schmeck kind of invented the things and he said, numerous times creatures will burrow down there to allow passages for water. I know the man and he didn't ever mention a screen. I am old, but not yet senile. Maybe by Tuesday I will be, but not yet.

I also didn't say anything about a nutrient dump or anaerobic disaster. At least I don't think I said that.

It is also not what happens in live rock. Live rock has maybe a milimeter of detritus in there. Much less than a DSB and 5 years is not old unless we are talking about socks.

I kept mine going for longer than that.

I feel, and I did end with "That is just my opinion" that after "a while" (I don't know how long that while is) the thing will no longer function.

Dr Ron Shimek is a very smart guy with more degrees than a thermometer, much smarter than I am in this matter (But I bet I am a better electrician)
This is part of his thesis:
Quote:

If there was no life in the sediments, there would be no layering. The layers are caused by the action of bacteria, micro-organisms, and animals which live on the sediment particle surfaces, and between the sediment grains. As these organisms metabolize, they use up the available dissolved oxygen. All of the oxygen in the sediments is consumed relatively rapidly, resulting in anoxic layers, wherein the only life is bacterial. Oxygen diffuses into the sediments from the water above the sediments, but such diffusion is very slow. In the absence of animals in the sediments, the aerobic and anaerobic layers would each be a few hundredths of an inch in thickness, and the anoxic layers would effectively extend to the surface. Such layering is found in highly organically enriched areas or in areas with toxic materials in the sediments. In these areas, animal life is absent from the sediments. These areas generally are polluted areas, but they don't have to be; there are naturally occurring areas that mimic mankind's best (worst?) efforts at pollution.

Here are some images of bacterial mats on natural anoxic sediment surfaces: http://www.geomar.de/projekte/komex/gallery3.html

Organisms and Sediments

Because organisms live on and between sediment particles, the interactions between those various organisms are what makes sand beds so important in reef aquaria. Bacteria, some microalgae, protozoans, and a few animals are small enough to live upon sand grains. To these organisms, the sediment bed, as such, does not exist; rather their whole world is quite literally a grain of sand. On this super small scale, the food web starts with the bacteria and microalgae, and on this scale, the microalgae are predominantly cyanobacteria and diatoms. These organisms live by absorbing dissolved materials in the water around them and by metabolizing those nutrients, creating more bacteria, cyanobacteria, and diatoms. Both the bacteria and cyanobacteria will also actively secrete enzymes into the surrounding environment, and these enzymes will breakdown organic particulate material so that it may be absorbed. There is sufficient light in all aquarium sediments for some photosynthesis to occur; light sufficient for photosynthesis generally can penetrate several inches or more into these sediments. The relative proportions and types of bacteria and algae in the sediments will depend upon the depth in the sediments, and the relative amount of dissolved oxygen available. In the upper layers of the sediments, diatoms and aerobic bacteria predominate on the sediment particles. In the anoxic lower regions of a deep sand bed, anaerobic bacteria predominate. In between, there is a transitional mix of several types of organisms, depending on the amount of nutrient, sediment disturbance and water movement.

I can give you the link for his entire article but I don't think I am allowed to put it here.

I think a DSB works great in nature. But I also think no one can get it to work well in a captive tank for many years as I feel they all have a lifespan and most other substrait systems don't. But if it works for you, keep doing it.

HuduVudu. I love you too and you may be much more right than I am which is why it is Just my opinion which may well be wrong.

 

[HuduVudu]

I remember when Dr Schmeck kind of invented the things and he said, numerous times creatures will burrow down there to allow passages for water. I know the man and he didn't ever mention a screen. I am old, but not yet senile. Maybe by Tuesday I will be, but not yet.

LOL ... yay being old

It wasn't Shimeck that invented this it was Jaubert at the Monaco aquarium. He did an unfortunate thing by patenting it. I think this really stunted it's introduction into the hobby.

I also didn't say anything about a nutrient dump or anaerobic disaster. At least I don't think I said that.

You didn't. It is another common fallacy that I wanted to address up front. Nope you're still not senile

It is also not what happens in live rock. Live rock has maybe a milimeter of detritus in there. Much less than a DSB and 5 years is not old unless we are talking about socks.

Anaerobic decomposition most definitely occurs in live rock, deep inside the rock. This is why porosity is highly valued in the rock. Don't tell my you put your old socks in your tank. At this point with everything else you put in there I wouldn't be surprised

Unfortunately I am one of those constantly moving guys and it is only been recently that I have settled down for long enough to get real longevity out of my tanks. I don't think I will live long enough to get the kind of longevity that you enjoy.

But I also think no one can get it to work well in a captive tank for many years as I feel they all have a lifespan and most other substrait systems don't.

Like I said I think that the problem in tanks isn't the bed or the theory it is the implementation. These systems are so poorly understood and maligned I don't think anyone cares about or wants one in their system. To me this is the same as "The Great Live Rock" debate. If only people understood they might be shocked at what they find.

I really like that Shimeck was advocating for this system. I am but a freak weirdo nobody, so for me to advocate for it is beyond eccentric.

FYI I am using this system to grow my coral.

I am NEVER wrong ... until I am ... which is quite often, but until then.

 

[BackToTheReef]

I don't know enough about the science to debate whether it is a good option, bad option, or neutral but here is what I do know. I like they way they look, I love all the critters they can have in them, and for me they just look more natural.

I had a dsb with a plenum made out of pvc, egg crate, and screen in my last tank which was a 75g. Paired with the live rock I had added it came alive. That's why I am looking at doing one in my next tank, now I might change my mind when I go to buy that much sand. I'll probably end up with it blowing all over and nuking something but I am going to give it a whirl.

 

[Paul B]

It wasn't Shimeck that invented this it was Jaubert at the Monaco aquarium. He did an unfortunate thing by patenting it. I think this really stunted it's introduction into the hobby.

I also remember him. I remember all the Geezers.

. Nope you're still not senile

I bet I am.

Don't tell my you put your old socks in your tank. At this point with everything else you put in there I wouldn't be surprised

Everybody here talks about changing socks, isn't what they mean.

I am NEVER wrong ... until I am ... which is quite often, but until then.

I thought I was wrong once, but I was mistaken.
I hope your DSB runs forever. Have a great day.

 

[robbyg]

I personally have never liked DSBs and used them in small local creature tanks. I even remember when they were invented and espoused by Dr Schmeck.

I believe the science behind them is flawed and they have a definite, short lifespan where they actualy do anything beneficial.
The theory is of course that worms and other creatures will burry down through the sediments, stirring it up so some water can get there. That only happens for a little while as there is no oxygen down there and as was said, probably hydrogen sulfide which is the exact opposite of what we want. Those worms also don't live very long.
I feel after a short while, a DSB may not crash the tank but it will be benign.
Just my opinion of course.

Yep same experience here. I ran one for about 5 years and it was such a relief when I finally got rid of it.

One of the things that you pointed out that was true for me is that at first it works well. I think that is what fooled me. At first mine did work well, I would say for the first 6 months and then things slowly got bad and the fact that it had worked well kept me fooled and looking for problems in all the wrong places. It was not until I removed the DSB 4.5 years later that within 3 months most of the issues cleared up. The main one being high Phosphate and something in the water like maybe H2S that was just giving all my corals a hard time. GHA was also giving me a hard time and I had not had that before the DSB started to run amok.

BTW when I pulled it out I found a lot of the sand just under the top layer had formed solid boulders of calcification. So that was where a lot of my Calc reactors output was going. Nothing was alive in the deeper dark layers and of course it smelled really bad.

Nope no DSB for me ever again, not unless it's a Mangrove based one.

 

[ichthyoid]

Fwiw,
I grew up in Florida, spent much of my youth exploring many miles of bays, tidal marshes, estuary’s & mangroves. Much of it was on foot & the smell of hydrogen sulfide was common when stirring up sediments. It is a gas, but also readily soluble & so I was always amazed to see lots of fish swimming in those same waters without any sign of being affected.

Also, I had a 125 gal reef with a plenum about 20 years ago. It had about 30 corals & maybe 12 or so fish. The reef was stable for over 3 years.

 

[burgundy]

Yep same experience here. I ran one for about 5 years and it was such a relief when I finally got rid of it.

One of the things that you pointed out that was true for me is that at first it works well. I think that is what fooled me. At first mine did work well, I would say for the first 6 months and then things slowly got bad and the fact that it had worked well kept me fooled and looking for problems in all the wrong places. It was not until I removed the DSB 4.5 years later that within 3 months most of the issues cleared up. The main one being high Phosphate and something in the water like maybe H2S that was just giving all my corals a hard time. GHA was also giving me a hard time and I had not had that before the DSB started to run amok.

BTW when I pulled it out I found a lot of the sand just under the top layer had formed solid boulders of calcification. So that was where a lot of my Calc reactors output was going. Nothing was alive in the deeper dark layers and of course it smelled really bad.

Nope no DSB for me ever again, not unless it's a Mangrove based one.

there's a huge difference between 6in of sand and a sand bed that's alive with a bunch of microfauna. there's where a lot of the dsb "hate" comes from, not adding life to the sand.

 

[jda]

I know that I only am near 3", but the thing acts like every one that I had that was deeper. They do not have a life span that I have ever seen. The thing is just as good today as it was six months after I set it up, but I do maintain it.

The high phosphate issues are with the reefer and the aragonite (sand and rock) not being able to mask poor husbandry any longer. Most do not even know that aragonite binds phosphate and sometimes in large amounts, but it cannot it forever and eventually fills up. The hobbyist either does not know their craft or has missed a lot of maintenance and then all of a sudden the P rises rapidly and they blame the sand - all that the sand ever did was to help the reefer with the P hoping that they figured it out. These "time bomb" posts and high phosphate opinons are because the reefer did not understand what they were doing.

 

[ReefBeta]

I thought DSB refer to sand bed like 5" or deeper. Couple inches deep sand bed in display is just a normal sand bed. Give it some proper maintenance and it can run as long as you want.