Do you know what a DSB is and should you or does it even matter?

[Glenn Etchart]

The big difference between promoting denitrification or the assimilation of nitrogen ( vodka, nopox, algae scrubber), in a closed system using a skimmer, is the fact the nutrient balance ( N ratio) can be restored by denitrification, not by assimilation.
A SB of +- 2 cm may have about the same denitrification capacity as a DSB without the risks involved.
As a DSB is a passive method, nothing can be managed. The denitrification capacity is unknown and limited.
If I have the need for removing a lot of safely stored nitrogen considered not needed I prefer to use active denitrification, giving the possibility for managing the removal rate.

We have 20 year established reef tank with hang on skimmer and canister filter the balance with the DSB has never been a problem but more likely a benefit to natural sea bed creation for longevity of tank. I have never tested other than salinity at water changes and have never had a problem.

 

[Glenn Etchart]

I am very interested in running a dsb when i finally upgrade to 120g (currently have a 35 with crushed coral). But where my curiosity lies with those who have had success or not, did you have the proper critters needed for a dsb. To clarify that point, all reef tanks are a recreation of a tiny chunk of the ocean. And the closer you can replicate the ocean, the healthier, and more stable, your tank should be as its a close to the real deal as you can make it. So i feel running a dsb is different. If your going to have one any sand imo, your gonna need to ensure that you have the proper critters need to inhabit that niche you created or it will almost certainly not be balanced and crash.

So who here has had great success with a dsb and what critters and regural maintenance did you do to help consume and keep nutrient levels in check?

I have a 20 year established 125 gallon reef tank with DSB. We do no testing and tank is fine with semiregular additions of nutrients and many crabs, starfish, snails, a few reef safe wrasses, Blennies that move the substrate around + vacuuming with your monthly water change.

water

 

[stanleo]

I really like the animals that need a DSB so I have one that is 3 to 4 inches. I vacuum it every water change. Tank is only 9 months old so we shall see if I have issues, so far there are none. I was actually hoping to keep garden eels but I think it isn't deep enough for them. I like the way the tank looks with it but if I had to do it over, I probably would have only gone with an inch or so.

 

[ReefLabs]

My .02
I've been out of the loop to some degree for a while now, but this feels like an ancient topic. My understanding is that a DSB at the end of the day, is a nutrient sink for undesirables. I was under the impression that the contemporary consensus was: sand beds require periodic maintenance to remove built up detritus and organics that aren't removed via other methods. The deeper the bed, the more effort maintenance requires. I'm not sure I'm seeing the need for it to be more complicated.

My assumptions on what a sand bed offers, functionally:
• bio-film surface area
• microfauna habitat
• minor buffering, calc/alk

I'm not seeing the need for a deeper sand bed than can be easily maintained, or any benefit to having long-term nutrient sink for that matter.

 

[Dana Riddle]

I can only relate my experiences. I had two reef tanks, one with a DSB and one without. When Hurricane Opal blew through atlanta in the 90's, we lost power for several days. I lost every coral in the tank with the DSB and none in the one without. I suspect the DSB consumed all (or a lot) of oxygen in the tank. I'll never know, as I had to be at work throughout almost the entire period. If using the DSB for nitrate reduction, I'd do it in the sump so the DT won't suffer.

 

[Belgian Anthias]

For the books - In order to maintain a good denitrification - a source of DOC (dissolved organic carbon) is needed (often methanol or ethanol ) - not mainly for the assimilation growth but for the anaerobic respiration there they serve as electron donors (nitrate is a electron acceptor in that process).

And there is no dubt that both DSB and different types of variation of it works - the dutch DyMiCo system is one working variant of DSB but it is an active system. My system is also a variant - and active

Sincerely Lasse

This is only true for heterotrophic denitrification!

DyMiCo injects organic carbon in a DSB based on redox readout, anoxic zones are created. DyMiCo does not measure the presence of nitrate in the DSB (2018), which, in my opinion, should be the main parameter before injecting more carbohydrates. The nitrate-nitrogen removal rate and the nitrate level can not actively be controlled or managed as desired, for example, to keep the nitrate level steady at 2ppm.

Active and passive denitrification can also be autotrophic which does not need any organic carbon. Good natural denitrification is mixotrophic. Autotrophic denitrification is an essential part of the functioning of a nitrifying and denitrifying biofilm, this way removing all HS produced within the film. This means the presence of nitrate is essential for removing all HS produced anaerobically. In anoxic conditions, where no nitrate is produced, this may become problematic. Also in a DSB .

Good and safe denitrification does not need any supplementation of organic carbon or and sophisticated computer programs and dosers. Good and safe denitrification does not need an anoxic environment, everything is taking place in normal aquarium conditions in a nitrifying biofilm. It takes place in the top layers of the sand bed where the water echange rate is sufficient to make a difference. No need for a DSB with anoxic zones created by a to low water exchange rate, too low to weigh on the total removal rate of nitrate nitrogen.
One can inject organic carbon in a DSB to consume more oxygen faster, making the anoxic zones bigger, but not more nitrate can be removed as N2 as the water exchange rate makes possible.

In practice, by growing a nitrifying biofilm on a mix of elemental sulphur and chalk, a nitrifying biofilter may remove all nitrate-nitrogen produced by the filter. ref: http://www.baharini.eu/baharini/doku.php?id=en:badess:bades:bades-kolommen.

 

[robbyg]

It's very true that this is hot button topic.
I had a lot of success Without a DSB then at one point I thought running one in the Sump refugium would be the way to go. It worked ok for the first year and after that it was nothing but trouble. I had huge Nitrate swings and all sorts of other issues. I ended up dumping it in one go in the third year and crossed my fingers that disaster would not ensue. Luckily the tank started looking better after just a month and only got better with time. I just have about 1.5" of sand in my tank. I think bare bottom would be better but it just looks unnatural to me.

 

[Lasse]

In practice, by growing a nitrifying biofilm on a mix of elemental sulphur and chalk, a nitrifying biofilter may remove all nitrate-nitrogen produced by the filter

In a normal aquarium - you do not have elemental S in the sand. The denitrification need electron donors - in the case with the heterotrophic denitrification its DOC and in the case of autotrophic denitrification elemental S is the electron donor - and it also result in production of SO3 and SO4

Good and safe denitrification does not need an anoxic environment, everything is taking place in normal aquarium conditions in a nitrifying biofilm. It takes place in the top layers of the sand bed where the water echange rate is sufficient to make a difference.

If you with this part means the dissimilatory nitrate reduction to ammonia - it is normally not refereed to be a denitrification process (or nitrate assimilation) It is a process of its own called DNRA. Anaerobic ammonium oxidation (anammox) its also a bacterial production of N2 of its own type.

Sincerely Lasse

 

[Dr. Dendrostein]

All I know, I love my sulfur denitrator. I'm at a steady stream now. NO3 at 10ppm, was 25ppm, before starting Sulfur denitrator. I do know, must keep eye on Ph, Ca,Alk, now

 

[Lasse]

All I know, I love my sulfur denitrator. I'm at a steady stream now. NO3 at 10ppm, was 25ppm, before starting Sulfur denitrator. I do know, must keep eye on Ph, Ca,Alk, now

Keep an eye at NO2 too!

Sincerely Lasse

 

[Dr. Dendrostein]

Keep an eye at NO2 too!

Sincerely Lasse

I do run effluent through coral sand before going into DT. I hope that helps?

 

[maroun.c]

One key consideration is lack of need for it now as improvements in swimmers and other mechanical filtration devices, as well as fosing methods have solved the po4 and No3 issue most of us struggled with and used a DSB for it. Some recently started even dosing NO3 to keep nutrients visible. Another change we see now is much more frequent dino cycles due to cleaner tanks we run. So guess the hobby took a path away from DSB.
RDSB remote Deep sand bed was my preferred method as it allowed u to reset the DSB every few years when needed.
I took my RDSB couple months back as it ended up acting like a detritus sink.

 

[lbiminiblue]

I am very interested in running a dsb when i finally upgrade to 120g (currently have a 35 with crushed coral). But where my curiosity lies with those who have had success or not, did you have the proper critters needed for a dsb. To clarify that point, all reef tanks are a recreation of a tiny chunk of the ocean. And the closer you can replicate the ocean, the healthier, and more stable, your tank should be as its a close to the real deal as you can make it. So i feel running a dsb is different. If your going to have one any sand imo, your gonna need to ensure that you have the proper critters need to inhabit that niche you created or it will almost certainly not be balanced and crash.

So who here has had great success with a dsb and what critters and regural maintenance did you do to help consume and keep nutrient levels in check?

I've had one basically since the beginning of my tank. 8 years or so. Have had jawfish in passing, never for very long, and diamondback gobies never lasted long either. However, I do have some mystery denizen worms that have created enormous mounds on the SB surface over time. I've seen them spitting sand up in the water column, forming these big mounds. No idea what worms they are or how they even got there. I have a few small nerites, but my CUC is extremely lacking. Sand bed varies from maybe 2-5 inches over the footprint of the tank.

 

[PhreeByrd]

Interesting thread, and I agree, this really is a hot button topic. Everybody wants what they are doing to be the "right" thing.
I've run both DSB and BB tanks, and never saw a big advantage to either one. Both have survived 12-hour power failures without any life support and without any issues.
The DSB tank has now been running almost 25 years. I never bother the sand bed. Except where my clownfish decides to move it around, I leave the sand where and as it is. I have a bumblebee snail that's older than the tank, and several nassarius snails that are at least 15 years old.
At least in my experience, the notion that a DSB requires maintenance is completely incorrect. The idea that it is a ticking time bomb of nutrients and toxics is pure nonsense.

 

[Belgian Anthias]

In a normal aquarium - you do not have elemental S in the sand. The denitrification need electron donors - in the case with the heterotrophic denitrification its DOC and in the case of autotrophic denitrification elemental S is the electron donor - and it also result in production of SO3 and SO4

If you with this part means the dissimilatory nitrate reduction to ammonia - it is normally not refereed to be a denitrification process (or nitrate assimilation) It is a process of its own called DNRA. Anaerobic ammonium oxidation (anammox) its also a bacterial production of N2 of its own type.

Sincerely Lasse

S is everywhere, also in the sand.
S is produced constantly in anoxic zones due to the anaerobic oxidation of HS using nitrate ( autotrophic denitrification). Depending on the HS:Nitrate ratio, S or SO4 and N2 is produced. It is part of the normal processes taking place in a biofilm. When the HS:Nitrate ratio is low or negative, the S reserve is used to keep the processes going, high enough to be ready for an increasing HS production.
S and nitrate play a main role in a healthy environment.
Providing more S in the substrate increases the total denitrification capacity and prevents HS accumulation in the presence of nitrate.
When in anoxic conditions nitrate is used up , sulphate is used as an oxygen source for anaerobic remineralization, producing HS.
In a DSB it may accumulate, in anoxic zones where nitrate is used up


In a normal nitrifying biofilm, about 15% of the ammonia-nitrogen entered may leave as N2 due to mixotrophic denitrification. No need for an anoxic environment. +-40% of the population of a healthy nitrifying biofilm consists of bacteria following an anaerobic pathway!
Adding elemental sulphur as a substrate for the growing nitrifying biofilm may increase the N2 production considerably.

It is obvious I did not mean DNRA!
Starting from nitrate, DNRA is the same anaerobic remineralization process as is normal heterotrophic denitrification, exempt, due to conditions influenced by the C:N ratio, at the stage of nitrite, ammonia is produced instead of N2.
Where heterotrophic denitrification takes place, in anoxic zones, always also DNRA takes place. The normal natural ratio is +- 15% DNRA. In a nitrifying biofilm, this is no problem as all the produced ammonia is reused. In a denitrifying biofilm kept in anoxic conditions ammonia is produced constantly and removed only by assimilation. Increasing the C:N ratio, injecting carbohydrates, shifts the ratio towards DNRA, more ammonia is produced. The presence of ammonia and free carbon will stimulate fast heterotrophic growth. This may be considered beneficial but may also lead to a clogged filter bed or and nutrient starvation, the accumulation of dead biomass in anoxic zones.
ref: http://www.baharini.eu/baharini/doku.php?id=en:makazi:bio-chemie:dnra
Anammox I have explained in an other discussion.!

 

[brandon429]

There is one thing I’m certain of

one group claims liability from sand

another group says that’s crazy they work fine with no liability

where these two groups never meet is in a thread where group B, success, fixes up mal performing sandbeds for group A live time using methods that made their tank work as measured

someone should change that trend and produce the first DSB diagnostics thread ever made. No theories, no biochem, or first person safety guarantees - just work in others tanks who state they have a problem and the tank is tracked until success



I truly believe group B has working sandbeds for decades, the catch is being there in person to veer off course/innovate action/know when to clean or add more sand etc

nobody writes a procedural manual that can be copied step by step, the first offer was add sand/ add plenum and get all the benefits. We know that doesn’t work well for everyone.

variability is linked with keeping sand in an aquarium, not consistency. If that’s an untrue statement then running a DSB diagnostics thread should be easy and there would be five we could already reference for patterns.

the number one reason nobody will make a sand performance tuneup thread is due to the stinging accountability when someone writes ‘it’s not working’ or by making the tank die/go through a cycle due to an access mistake.

Working with other people’s sandbeds isn’t a safe zone like listing biochem steps that make things great on paper. The greatest update to sandbed science will be from an action thread using others tanks, only that direction of work establishes proofs.

Somebody with sandbed control ability, start that thread. We don't want to see your sandbed, show us the ones you guide using tenets associated with successful long term sandbed use.

 

[Lota Reefer]

S is everywhere, also in the sand.
S is produced constantly in anoxic zones due to the anaerobic oxidation of HS using nitrate ( autotrophic denitrification). Depending on the HS:Nitrate ratio, S or SO4 and N2 is produced. It is part of the normal processes taking place in a biofilm. When the HS:Nitrate ratio is low or negative, the S reserve is used to keep the processes going, high enough to be ready for an increasing HS production.
S and nitrate play a main role in a healthy environment.
Providing more S in the substrate increases the total denitrification capacity and prevents HS accumulation in the presence of nitrate.
When in anoxic conditions nitrate is used up , sulphate is used as an oxygen source for anaerobic remineralization, producing HS.
In a DSB it may accumulate, in anoxic zones where nitrate is used up


In a normal nitrifying biofilm, about 15% of the ammonia-nitrogen entered may leave as N2 due to mixotrophic denitrification. No need for an anoxic environment. +-40% of the population of a healthy nitrifying biofilm consists of bacteria following an anaerobic pathway!
Adding elemental sulphur as a substrate for the growing nitrifying biofilm may increase the N2 production considerably.

It is obvious I did not mean DNRA!
Starting from nitrate, DNRA is the same anaerobic remineralization process as is normal heterotrophic denitrification, exempt, due to conditions influenced by the C:N ratio, at the stage of nitrite, ammonia is produced instead of N2.
Where heterotrophic denitrification takes place, in anoxic zones, always also DNRA takes place. The normal natural ratio is +- 15% DNRA. In a nitrifying biofilm, this is no problem as all the produced ammonia is reused. In a denitrifying biofilm kept in anoxic conditions ammonia is produced constantly and removed only by assimilation. Increasing the C:N ratio, injecting carbohydrates, shifts the ratio towards DNRA, more ammonia is produced. The presence of ammonia and free carbon will stimulate fast heterotrophic growth. This may be considered beneficial but may also lead to a clogged filter bed or and nutrient starvation, the accumulation of dead biomass in anoxic zones.
ref: http://www.baharini.eu/baharini/doku.php?id=en:makazi:bio-chemie:dnra
Anammox I have explained in an other discussion.!

Fascinating description thank you. I seem to be reading that there are reefers who want to reef via tech, others via chemicals and others still bacterial. The mixed success seems to come when one tries to blend different methods. I am totally intrigued by bacterial methods and am moving my personal journey in that direction. This explanation is not the first time I am seeing that bacteria take their oxygen based on their surroundings as in from 02, then n03 then p04 and when all that is depleted into sulphate etc. After all the 0 is those are oxygen. What amazing creatures. Thanks again for sharing...off to read your link.

 

[Paul B]

Also ole PaulB probably is witnessing friggin primordial evolution in that old sand of his, so who knows anything for certain....

What do you mean "ole" PaulB ?

 

[Lasse]

Starting from nitrate, DNRA is the same anaerobic remineralization process as is normal heterotrophic denitrification, exempt, due to conditions influenced by the C:N ratio, at the stage of nitrite, ammonia is produced instead of N2.

As I understand it DNRA is a reduction process and denitrification is an oxidation process - they are not similar - they are opposite each other.

Sincerely Lasse

 

[Doctorgori]

What do you mean "ole" PaulB ?

LoL btw anything “evolve” in that tank yet?