Deep Sand Bed (DSB) - The unpopular opinion

jda

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To me, DSB is a term that relates to a sand bed that acts as filtration, nitrate reduction and houses all kinds of microfauna and sand cleaners. This is not cosmetic, but serves a purpose in the life cycle of the reef tank.

I consider my 3" sand beds a DSB since they provide this function. They do not have to be 6" inches, IMO.
 

HuduVudu

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To me, DSB is a term that relates to a sand bed that acts as filtration, nitrate reduction and houses all kinds of microfauna and sand cleaners. This is not cosmetic, but serves a purpose in the life cycle of the reef tank.

I consider my 3" sand beds a DSB since they provide this function. They do not have to be 6" inches, IMO.
To further I believe that DSBs are a derivative of plenums and the purpose of plenums was to provide anaerobic zones, for whatever benefits came from that. If you are getting anaerobic zones at 3 inches then in my mind it is a DSB.
 

robbyg

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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.
Mine was over 6 inches deep and it initially had a lot of critters in it. I did not put a huge amount of maintenance into it but overall it just became more and more problematic over time. And I was using white sand about 1-2mm sized particles with a thin 1" broken layer of mangrove mud about 3 inches below the sand and the another about 3" of white sand until it hit the bottom. Who knows maybe I did not set it up right, it seemed to thrive for a long period with tiny worms and all sorts of life in it before it just slowly stopped. Thank God it was in my sump, it made removal so much easier.
 

burgundy

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is there any sort of way to test if the water is oxygenated at the bottom of the 3in of sand? if it's sugar fine sand that would block the oxygenated water faster then bigger grain of sands
 

robbyg

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is there any sort of way to test if the water is oxygenated at the bottom of the 3in of sand? if it's sugar fine sand that would block the oxygenated water faster then bigger grain of sands
I am no expert on DSB but I would think you do want a certain amount of flow to be going through the sand bed. I have been to beaches that have powder like sand and when you scoop up a bucket of it the layers just below the top are black and anaerobic and smell real bad. I don't see anything alive in it.
 

burgundy

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I am no expert on DSB but I would think you do want a certain amount of flow to be going through the sand bed. I have been to beaches that have powder like sand and when you scoop up a bucket of it the layers just below the top are black and anaerobic and smell real bad. I don't see anything alive in it.
imma check that out next time i'm at a beach
 

Osidedude

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The beauty about this conversation is every tank is different and some people love dsb's and some dont. I keep a dsb because of the fish I love which thrive in sand beds (jawfish and many types of gobies) even though I have a jawfish & gobies that have been without sand for almost a year as I build my dream tank and set up.
 

HuduVudu

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I am no expert on DSB but I would think you do want a certain amount of flow to be going through the sand bed. I have been to beaches that have powder like sand and when you scoop up a bucket of it the layers just below the top are black and anaerobic and smell real bad. I don't see anything alive in it.
The only flow through the bed is through diffusion in these systems. You can and I do use pumps to set up flow through beds, but the DSBs and plenums rely solely on diffusion for water movement.

I think you are misunderstanding what is happening in the bed. There is no fauna in the anaerobic zone only bacteria. The bacteria are converting organic waste. There are several by products in the conversion one of them being hydrogen sulfide the bad smell you keep referring to. This is a normal part of the conversion process and does not impact the biome that it is in. Most hydrogen sulfide is either converted to sulfate or out gassed once it reaches aerobic zone. One other point is that some of the hydrogen sulfide will be catalyzed through another bacterial process with iron this is the black part of anaerobic decomposition.

The aerobic zone right after the anaerobic zone is what benefits from the the byproducts and the fauna will be heavy in this zone.
 

robbyg

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I do know what the bad smell is. I run a sulfur reactor which replaced my DSB.
It gives me a lot more control on my nitrate levels with almost no maintenance.
I am happy for those people that have had a very good experience with DSB. That’s the great part about this hobby, the fact that in certain areas there are multiple paths to success.
 

Paul B

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imma check that out next time i'm at a beach

Thats a good Idea as I am at the beach every day and am going there now. :p
It all depends on the size of the sand particles. This tide pool in NY has very find sand and 1/4" below the surface is jet black, nothing but hydrogen sulfide and nothing, not even a worm lives in it.



This beach behind my house is an ocean beach and the sand is a little courser. Here you can dig as deep as you like and the sand and water under is clean and smells fresh.



It's all about particle size, water movement, amount of organic matter and a few other things. We can't quantify these things in a tank because there are to many variables.

We should also determine what is a successful DSB, tank, coral or anything else.

To me this is a lifelong hobby so if I say something has great success I mean it is self sustaining "forever" with no degradation over time. The thing is eternal and never ending unless there is some catastrophy that has nothing to do with the natural process of the thing.

6 months or even 10 years means nothing when we are talking about something that is supposed to be an ongoing, self adjusting ecosystem :cool:
 

Buffalou

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I have had very good success with DSB in fuge and bare bottom in Display tank, I used it to help season build I did 1 1/2 years ago. Going to be moving to new tank so now that rocks and tank is seasoned I'm planning to slowly eliminate it , I believe. I can use the room in fuge for additional equip for larger tank. Was wondering if anyone has done this?
 

jda

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6 months or even 10 years means nothing when we are talking about something that is supposed to be an ongoing, self adjusting ecosystem :cool:

My sand bed has been every part of that ongoing ecosystem. This current one since about 1998 and that was only interrupted because I graduated and had to live with my parents for a few weeks (had I know I would have been there so short of a time before finding a career, I would have set the old one back up again). However, like I have said, it does get maintained.

Are you all keeping beaches and tide pools in your home? I thought that you all had reefs? Might be a good idea to check out a reef that is actually under water, tropical and has some coral living/around in it. :) Some tide pools are a mess in the Coral Sea too and the reefs 20-40 yards away are beautiful and teeming with life.
 

tvan

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@Paul B I think beach sand has a higher turn over rate then sand in tidal pools. And most DSB's are always under water. Or am I missing something. And I too have socks older then five years... :)
 

ChrisNH

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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

That’s really interesting. While I am a relative newcomer to owning a marine tank, I have been researching for a long time and watched the evolution of this. Recent conversation and my understanding was that you either had 1-2" of "decorative" sand bed or you went full Monty 5-6" DSB and "here there be dragons" as far as most retail reefing tutorials are concerned. 3-4" was the no-man's land of "no benefit" from dsb and "too hard to clean" vs shallow.

Much more recently I have found that some experienced and successful reefers I follow are actually right in that 3-4" and having a lot of success. My thinking on this is evolving. My current tank is a 40B, so a DSB would have turned my tank into an ant farm, but for my next I still love the idea.

I would love to see some controlled experiments done with 2", 4", and 6" of sand bed and periodic core samples taken and analyzed. I think this would be huge for the hobby as this one question still resonates with following "The Gourd" or "The Sandal".

Anyway, thanks jda, you put up front what has been rolling in my mind the last few months.
 

jda

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Go to wet web media if you want to see anything "like" an experiment. Hobbyists are not good for this since they will blame anything at any time and always make changes to ruin their control - a little bit of algae and all of a sudden the sand bed is the devil and has to come out. WWM has a lot of experienced actual pHd that used to answer questions - the forum is a mess and it takes a while to get used to, but there is lots of good info. However, biology and chemistry has not changed since people started to reef, so the information is still good.

I have posted a few places where my opinions differ from theirs with the 1). depth with three inches being totally fine and 2). not ever cleaning the sand bed where I like to vacuum the benign detritus out of the sand bed over the years. Otherwise, I think that they get this pretty well.

I assure you that you can get very good denitrification with an average of three inches of sand. Mine has been undetectable for decades and with the new emergency of ICP, I can say that it is at .1 ppm, which is about ocean level where they use DSB too (I kid, but only kind of kid).
 

ChrisNH

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I assure you that you can get very good denitrification with an average of three inches of sand.
Melev's Reef also runs around 4" I think. Thats what first raised my eyebrows and started me questioning the "1 or 6" thing.
 

scchase

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I have live rock I got for Christmas in 1992 (yep I go rocks for Christmas and was happy, this was the real Florida stuff you used to be able to get for around a dollar a pound). Much of my sand was bought in 2004 when we used to truck in pallets of Southdown sand the rest is stuff that I have picked up from hobbyists getting rid of it over the years. I can't say that I really have ever had a problem with any of it, every few years I do like to siphon it lightly to get the detritus out but that is about it, my depths range from 3-6" depending on where dunes have formed. After a while it adjusts to the current in even the highest flow tanks and stops moving around as much. In all I probably have around a ton of sand between my various systems and better than 1500 pounds of rock. I have toyed with the idea of setting up shallow flats in stacks plumbed into each other over the years filled to 4-5 inches of sand and only a couple inches of water on top, just never got around to doing it, that and finding enough sand in Colorado to do it may take a while.
 
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