Is DSB crash just a myth?

[SteveG_inDC]

I can't tell you how many times I've read warnings on discussion boards about deep sand beds (DSBs) risking a tank crash if the anaerobic layer is disturbed and toxic gases are released. I am beginning to think this is a myth. There is no good evidence for it and very few first-person testimonials. On the other hand, DSB enthusiasts note that they've had them for years or decades with no problem (and lots of benefits, including stabilizing alkalinity).

Are there credible first person accounts of DSBs poisoning their tanks?

 

[ScottR]

I can't tell you how many times I've read warnings on discussion boards about deep sand beds (DSBs) risking a tank crash if the anaerobic layer is disturbed and toxic gases are released. I am beginning to think this is a myth. There is no good evidence for it and very few first-person testimonials. On the other hand, DSB enthusiasts note that they've had them for years or decades with no problem (and lots of benefits, including stabilizing alkalinity).

Are there credible first person accounts of DSBs poisoning their tanks?

@Mastiffsrule

 

[ndrwater]

@Paul B

 

[Butuz]

I have a diamond goby that has tripled in size constantly shifting through the top layer of sand. He also moves tons of rock when creating new layers under rocks. Haven’t had any issues so far. Constant turning and agitation by the goby may be the ticket.

 

[ahiggins]

TLDR: this is definitely a thing. Unknown in reef tank of what degree/how much bacteria build up would cause a crash.

I’ve never experience it in a reef but I’ve experienced anaerobic bacterial growth MANY times in my career. I work mainly with environmental sector and I’ve overseen the “restoration” of waste treatment facilities. Not necessarily human waste though lol hazardous waste mostly.
The distinction between aerobic and anaerobic comes from the ability to get oxygen to the sub layer-a fact that’s pretty much accepted. When you get >4”, there is very little to no exchange of gases. When that layer gets disturbed, it releases gases (depending on the type of bacteria growing). I’ve always had it release a form of sulfur gas-easily identified by the initial smell. I say initial because sulfur compounds are unique in that after a few minutes the smell goes away because it damages your receptors so you aren’t able to smell it. That’s when it starts to become toxic for humans depending on the environment it’s in.
I’ve had to evacuate whole buildings because of this in the past. It’s not a good situation and it usually transpires around the 5-10 minute mark depending on how big the system.
the concept of this 100% occurs, there’s no doubt about it. Depending on the chemical reaction taking place, the oxygen sometimes reacts with the gas and a new gas “replaces” it. In essence starting as oxygen and reacting turning into not oxygen lol (I’m not a scientist so I can give you a formula). That being said, it’s plausible that the reacted gases can replace oxygen and suffocate anything that needs that oxygen to stay alive. What I don’t know in the hobby is-at what point does it become deadly to fish.
personally I will never run a dsb because of that unknown.
for reference, this buildup of bacteria usually takes about 2-3 weeks of anaerobic growth to become an issue when it’s released. The longer it goes (and the more sub layer surface) the worse it is.

 

[Mastiffsrule]

Hi all,

Can’t give first hand experience on this one. Never ran one.

Your thoughts on it being a myth are more reality in my readings over the years. I have yet to come across someone who has properly run one come on and say they lost an entire tank one day when they accidentally stirred up their 3 years old Dsb .

I am not an expert but I am not sure the hydrogen sulfide could reach that toxic a level to take out a tank. Now a local effect yes.

 

[Salps]

Mine was fine for a couple years then I had a hard time keeping nutrient levels down. Did my tank crash? No. Did it grow algae really well... Yes. I sucked it all out with a shop vac and never looked back.

 

[User1]

I don't believe you are going to find what you are looking for if truth be told. The simple answer is does Mother Nature run a bare bottom ocean? No, she doesn't. However, what she has over us besides good old smarts is surface area and a cycle of life like nothing else. So while my reply is a bit snarky, I admit it, the realistic answer when we all remove our personal bias is that no, it isn't a myth that it will crash, or will not crash.

There are successful reefs running bare bottom, dsb, rdsb, substrate of this color, that color, and a combination of them. There are also failures. Have a plan. Prepare. And above all have some patience. Nothing in this hobby is done overnight be it good or bad.

Edit: forgot to add that there are also failures running similar combinations of beds and substrate. To include bare. I guess my point is if you know what you are after going into it I think you will be ok.

 

[ca1ore]

An improperly managed DSB certainly could crash a tank, so in that sense it’s not a myth. I do think the risks associated with a DSB are heavily exaggerated though. I’ve run one for most of my 30 years in the hobby and never had it crash my tank.

 

[OrionN]

It is just a myth. I keep DSB of fine sand. In my 420 my sand bed were 3-4 inches in front and 7-8 inches in the back. Plenty of time this bed was disturbed. No problem.
Right now my sand bed in my 320 is 5-6 inches in the back, bare to 3 inches in the front. I stirred it up all the time. Zero problem. My QT system have 4 inches bed in a 40 gal breeder. This was disturbed plenty with no problem.
My Nitrate always run near 0. I have problem with keeping phosphate under control due to my heavy feeding, but never nitrate problem.

 

[OrionN]

DSB is full of life, and use a lot of Oxygen. When power go out, DSB tank crash much quicker and more severe than bare bottom tank due to the density of life in the DSB. That much is true. There are a lot of worm live in the anaerobic layer of the sand. These worms have methods of pump fresh water down their tunnels and thus get O2 even if the tunnels itself in in the anaerobic dept in the sand bed.

 

[outerbank]

Its one of the most detrimental myths in the hobby. As OrionN says, and IMO, use very fine sand. After that, everything is a piece of cake and sand loving corals and animals will all have a nice home. A thriving live DSB consumes and breaks everything down to basic elements. It does not accumulate toxic substances, it consumes them and converts them to essentially living organisms, CO2, H2O, and simple gases which slowly bubble off.

 

[Cory]

Yes of course they work just look how clean swamps are.

 

[brandon429]

Search the web for threads that show how to move tanks between homes as a reference, don’t accept just personal testimony. See what can be done with the truth, as claimed, to see if it’s truth.


if you can find one thread above ten pages that moves tanks keeping the sand intact, full waste and sand life transfer, then you can make a case sandbed waste is harmless. But if you cant


*my above calibration does two things:
- validates long running sandbeds. Undisturbed, they can work years on a bell curve. Seek out what happens when it is time to disturb and check for unplanned disturbance- rock slides and powerhead dislodging included


-work example threads remove personal testimony as the basis for truth and instead exposes patterns, if they can be found. If sandbeds are harmless, then hands off advocates will be doing work to prove it vs just posting first person opinions. These patterns are easily logged in web threads. People have to move homes, there’s a need for this science and they’d prefer not to lose bacteria, of that I’m sure.


Work threads are other people’s tanks, not our own as examples.




if indeed the only thread you can find about moving tanks home to home involves total sandbed cleaning, then a case can be made that sandbed crashes are real, and patterned events, and it takes surgical precision to work with aged sandbeds in work threads outside our home examples.

we should speak in the currency of work links to answer this claim.

someone that has a pile of detritus on the bottom of a sump, oxidized, isnt in the same risk bucket as a reefer who locked it away from oxygen up under a pile of live rocks. A works thread exposes the claimant to variation, truths are evident by page twenty.

 

[blstravler]

I don't have what I would consider a DSB - it's about 2in's maybe a hair more. After seeing a recent BRS video about taking care of sand and vacuuming it I decided to give it a vacuum. In my tank I have a pretty decent size clean up crew including plenty of snails to help keep my sand "clean" so I thought it would be pretty 'clean' - I'll be honest what came out of my sand was troubling to say the least. The water was black - and the smell was repulsive. Doesn't mean it would have caused my tank to crash but I thought I would just chime in on this post as it might be somewhat good to know.

 

[brandon429]

We should start a new work thread. Personal testimonies never progress things, only traceable application

-sandbed maintenance: how to design, move and handle sandbeds in a safe manner and take care of sandbed invasions


it will be a preservation work thread, no rinsing allowed. Full cloud stays in every tank, handled naturally of course.


someone post that or something similar you will get constant work requests. You want to do this so that the ideal arrangement start to finish can be reflected in patterns, reinstating traditional sandbed use in the hobby. Step out of personal testimony into the coliseum

Take back ground from rinsers and bare bottom advocates, those do have work threads to pattern scope. prediction for this thread: all personal testimony not one works link even by page five. Scholarly links, university studies and personal testimony but not one single application for another aquarist undergoing challenge logged.

And hands off sandbedding will still win new adherents anyway heh

 

[jda]

You won't find many true accounts of this, and most that you will find are exaggerated and usually from badly maintained tanks where something else is to blame.

Sand mostly gets blamed for rising phosphates after a while, but the sand is not to blame for this, it is the hobbyist. Aragonite binds phosphate, so the sand covered up the bad husbandry of the hobbyist until it could not anymore and then the levels start to rise. If you still do your maintenance, this does not happen.

IMO, sand crashing tanks is right up there with "had lotion on my hands," "the neighbor sprayed for bugs" or "roommate poured something in my tank" type of myth status.

While people are basing sand beds and the biodiversity in them, let me offer a positive that most do not consider: I have never had any issues with ich or other parasites in tanks with mature sand beds. The microfauna in the sandbed are always looking for food and ich cysts that drop into the sandbed appear to be plenty tasty.

IMO, the misinformation about sand beds is nearly as prevalent as people who think that dry/dead rock is the same as live rock after it gets wet and you add a bottle of bacteria.

 

[Super Fly]

An improperly managed DSB certainly could crash a tank, so in that sense it’s not a myth. I do think the risks associated with a DSB are heavily exaggerated though. I’ve run one for most of my 30 years in the hobby and never had it crash my tank.

@ca1ore does DSB require periodic maintenance, if so what is involved please?

 

[jda]

Simon can answer for himself, but here is what I do with mine... in about year 4, I vacuum small sections of it every few months to where I get it all in about a year. This removes the gunk (benign detritus) that can "clog up the works." I also replace some if it since it melts with the lower pH down where the bacteria are working in the anoxic areas.

I have some cucumbers and a few conchs that keep the top layers in good shape.

 

[Neoalchemist]

Ive run a deep sand bed 6" plus but with a plenum and the top 3" or so was separated from the rest with a screen to keep it un- disturbed.
In this case the sand was conscidered a part of the filter. The tank was a success for about 6 years until an address change. When I broke it down the sand was plenty grungy but never had problems and did not smell like rotten eggs( hydrogen sulfide).