Are Deep Sand Beds, DSBs, dangerous to use in a marine aquarium?

[JPMagyar]

It's all a bit OTT to me!

Does it biol down to people recommending to use/not use them with new hobbyists?

Ding! Ding! Ding!

Give that lassie a wee littl' prize.

No, seriously. I think you have analyzed the situation perfectly. Some folks feel that a DSB is the death knell of an aquarium whilst others say pish-posh.

Me, myself, I say pish-posh, but that's just because I wish I was English. You know . . . accent envy and all . . .

Hey has anybody seen my video? Did you know it has almost 30,000 views

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There must be a whole lotta bored people out there :rollface:

 

[crissie]

I thought that might be it!

Meh, I'm a Northerner - I also have accent envy for the Queens English, it's usually tish-tosh though

Your tank is gorgeous - how do the chromis get along in that size group?

 

[JPMagyar]

The chromis fight constantly, but I still have 15 of the original group. In my tank it took a group larger than 13 before the aggression evened out and they all survived. I tried initially with only 7 and that didn't work.

 

[flyingpolarbear]

This past weekend I finally changed the sand in my 14 year old 5" DSB because I had a major tank meltdown from equipment failure followed by cleaning vinegar filling the tank overnight. Anyway the DSB was fine, I would use a DSB again. The parts that had buried organic debris (from back when I was a beginner) had dark grey sulfur looking areas, but the areas sheltered by huge live rock pieces had nice white sand all the way through. I think a DSB works fine if you don't bury stuff in it. I had a clam that lived about 10 years and grew quite a bit, until I put a clam eating snail in the tank by mistake. Clams and certain corals did well, but not SPS.

 

[Sleepeatcorals]

Hey guys this is SleepEatCorals!!! I have read a lot of your comments on this post!!! And I see a lot of stuff you guys are missing out and not taking in into conclusion!!! What is the one thing we learn in this hobby? anyone? Patience!! This is one thing that people have problems the Most!! 2nd largest thing I've seen is so many mixed answers!!! Where am I getting at here... Here's the the thing DSB I can go on any forums and read pages about Bad comments on them!!! You know what's the best part ask them if they ever had a DSB! They would say NO, and that's what bugs me, people are gonna listen to what other people have to say about them!! Also how can you determine if it was DSB killed your tank, in this hobby we know it could have been a Thousand things that could have cause it....

Am I Right or Wrong Guy?

Here are some Mistakes I've seen people mistakes that caused crashes and blame the sandbed when it was their own mistakes!!!
1. Mixing your Sandbed!!! Yes why would you mix your sand bed?? Their are millions of microorganism living in your sand bed that is very beneficial to your tank and sandbed!! And another thing sandbed is your 2nd main biological filtration. When mixing your sand bed you are releasing gases in your system, the microorganism help break these gases down!!! You never hear don't mess with you sandbed??

2. Detritus!!! Why are you worried about this... If you have a good flow that hits your sand bed you are gonna be fine!!! I see so many people have no flow on the bottom of their tanks. That gonna cause build up of detritus and it's gonna cause problems in the long run!! Their are many inverts that feed off detritus and especially for sand the sandbed!!! You have Nassarius snails, sand sifting starfish, Gobies, and conch snail I might be missing a few but these are beneficial to your aquarium and your clean up crew! And many people don't have this... Try to replicate the ocean as much as you can!!

DSB in my eye are very beneficial for filtration, but also giving nutrients to your corals, Fish, and etc. ampipods, bristle worms and many other microorganism living in the sand bed eating the bad particles the sand bed creates to clean your system!!! Don't worry about what people say read some of these books out their, and read about the great barrier, and all these great reefs that are out there!! Stop reading what people say and learn from the books!!! These books have so much knowledge and facts about the reef!! Most of these 20 years plus Hobbiest that you see with these amazing tanks have read these books!!! And their not gonna go on forums and tell you everything!! Why because people will start to disagree and say that a bunch of BS!!! I know guys have seen it!! Why a lot of these experts don't say nothing!!

 

[skinsncanes]

Hi Guys,

I'm setting up my tank now and have a question about DSB. Im builing my tank around getting a pair of coral cat sharks. Ill have around a 300 gallon tank. I have a life reef wet dry filter for biological filtration. Ill probably get ~200 pounds of live rock and try and make an arch in the center of the tank while keeping a path for the sharks to do laps.

My question is since I am planning on have a fish only tank, can I still have a deep sand bed? I read in several of the posts that the breeding that occurred in the sand bed provided food for the corals. I wasnt planning on having things that would eat the various sand critters. I can get them as long as they arent also food for the sharks.

I like the idea of a DSB ismply because Id rather let nature do the work. Why would I want to vac out the sand when I can have worms do it for me right!?!

Thanks

 

[Reefin' Dude]

I like the idea of a DSB ismply because Id rather let nature do the work. Why would I want to vac out the sand when I can have worms do it for me right!?!

Thanks

it would be great if it was true, but it is not. what eats the worms poo? poo/detritus being there indicates that it is not a perfect system and waste is being created.

the biggest problem with waste material is the phosphates. the easiest way to see why DSB's are not complete is to look at any phosphate cycle chart. there is not a phosphate export mechanism from substrates in the marine environment. the only way P is exported from substrates is through the removal of the substrate itself from the environment. in nature this is through plate tectonics or through major disruptive events of the substrate, not through critter or bacterial activity.

G~

 

[sellmecorals]

macroalgae uses phosphate, thats natural

 

[jda]

Everything that grows uses phosphates. This includes microfauna in the substrate, as they multiply, algae, coral, coraline and everything else. Everything.

 

[tmz]

If you want deep bed it can be managed . However, it won't do very much more than a shallow bed for nutrient control. Not much bacterial activity occurs beyond the first half inch or so.

It takes a lot of effort to keep a deep bed vital including chores like: partial sand replacement from time to time and replacement of some of the fauna. Some folks like to do that ;many find they spend more effort keeping a deep bed than they originally thought ;some seem to enjoy the activity.
All living things use some phosphorus, even the bacteria in a sand bed but not many of them live deep since they don't get enough nutrients( organic carbon, nitrogen, phosphorous, an oxygen source moved down there for them to use.

A deep bed may or may not serve as a phosphate sink depending on a number of variables infuencing how much PO4and what species realtive to argonite binding strength actualy finds it's way deep into the bed. I have not seen any data useful on this.

Deep beds or pockets of deep sand are needed for certain animals like long tentacle anemones, jaw fish, burying wrasses etc. and there is nothing wrong with using them or pockets of sand in the tank. Aside from that I personally don't see much upside to a deep bed unless you like the aesthecs and sand critters.

When maintained well, they can last a long time. There are some who have kept them functioning for over ten years. FWIW my best run was 7yrs. I no longer use deep sand beds in my aquariums and haven't for years. I don't miss them,

 

[Wazzel]

I ran a 6" DSB in a 110 for 3 years. When I pulled it out to move it was nasty. I am not going to run the risk of that in my tank ever again.

 

[jda]

You don't have to let them get nasty. Vacuum them every once in a while... slowly.

I use about 3" sandbed anymore, but I would not have a tank without one. ...no detectable N or P without using any organic carbon, GFO or the like. Not bad for a 15 minute vacuuming every 6 months, or so.

 

[sellmecorals]

People build up bacteria during cycle by throwing in a dead shrimp right?

Does dead microfauna also get used by bacteria of a dsb or live rock, and does microfauna feed on that same bacteria while alive?

Or, do microcorpses lead to an unusable saturated substrate that absolutely requires changing? Wouldn't the anoxic layer, if left undisturbed "complete the loop" circle of life?

We know for a fact there are processes going on in the ocean floor but can it all be scaled down? What other factors would play into a self sustaining ecosystem with just flow and light, if I could be so ignorant to ask. What else does a reef have.. water, sand, sun, wind, life, death, anything impossible in a tank? ....thinking out loud

 

[flyingpolarbear]

I have a theory that to keep a dsb thriving, you need to feed enough, which is tricky to determine because too much leads to excess nutrients but too little causes die off and I guess another kind of excess nutrients, or would it be just a lack of benefit per chunk of sand?

I had a DSB for 14 years and tried numerous experiments. Things were smoothest with carbon (bacteria nutrient) supplementation (I used ZeoStart 3) plus ozone.

 

[tmz]

people build up bacteria during cycle by throwing in a dead shrimp right?

Ammonia is created by the decomposition .This brings nitrogen into the biological realm.

does dead microfauna also get used by bacteria of a dsb or live rock, and does microfauna feed on that same bacteria while alive?

dead organisms decompose and feed bacteria.
Depends on the organism and the type of bacteria.

or, do microcorpses lead to an unusable saturated substrate that absolutely requires changing?
They could contribute to a fouling sand bed but I'd put more weight on decaying food and other forms of detritus and bacterial mass along with potential anoxia in some areas.


wouldn't the anoxic layer, if left undisturbed "complete the loop" circle of life?

No, the nitrogen will turn to N2 gas in hypoxic conditions,ie with nitrate available when there is no free oxygen. No need for an anoxic area( no oxyugen and no nitrate) in a closed system as sulfate reduction will be common there if some organics are present and that leads to toxic hydrogen sulfide. Some other processes can also occur producing toxins.

we know for a fact there are processes going on in the ocean floor but can it all be scaled down? What other factors would play into a self sustaining ecosystem with just flow and light, if i could be so ignorant to ask. What else does a reef have.. Water, sand, sun, wind, life, death, anything impossible in a tank? ....thinking out loud

Dilution at the level in the ocean is impossible . An estiamte of the water change per cubic meter of water about 265 gallons) on the great barrrier reeef runs around a million gallons per day.
Further the concentration of life activity relative to water volume and surface area for gas exchange in even the most sparsely stocked aquariums is exponentially greater than in the sea.

The supply of nuttrients and other elements is much more consistent and comprehinsive than we can prelcisely mimic.

The pressures at depths on the sea floor are also much different. We know for example the anammox bacterria remove nitrogen there but they also produce hydrazine( jet fuel) toxic stuff but not an issue in the large water volume. Methane is also an end product of degradation but i don't think we will see it or want it in a reef tank.

In short ,the little droplets we keep are not comparable to the oceans

 

[Reefin' Dude]

Variable rates of phosphate uptake by shallow marine . carbonate sediments:
Mechanisms and ecological significance

Phosphorus accumulation in marine sediments and the oceanic phosphorus cycle

The Marine Phosphorus Cycle

The phosphorus cycle in coastal marine sediments.

macroalgae uses phosphate, thats natural

as stated earlier all living organisms use phosphates, but not in the way most people think. it is how living organisms create energy to live. very little of the phosphates stay in an organism. P is constantly on the move. macroalgae and the like are great P converters. converting inorganic P to organic P, but they are retaining very little of the P that goes through them.

the thing to remember about P is that we are only able to test for inorganic P. that is a very tiny part of the entire P puzzle. think of it as only having the edge pieces of a puzzle and thinking that the puzzle is solved because your P levels say 0.

when discussing algae as a P binder one must also know how algae uptakes P, and where the P that algae is able to uptake originally comes from.

following P is a long and involved rabbit hole of research. cycles and processes that one thinks have nothing to do with P all of a sudden are very reliant or hindered by the presence of P.

a good way to start getting ones feet wet in the deep end about P is to read up on the Calvin cycle, ADP, and ATP.

G~

 

[Fredfish]

Here's an interesting read on nitrogen in the sand bed.

 

[tmz]

Thanks Fredfish.
The article provides a nice summary on denitrification and the "redox cascade".It's a good read. One point though, I don't think we can assume tanks have enough iron available in deep sand beds to offset concerns about sulfide and I am unaware of any data to support that idea. On the other hand excessive iron can spur nuisance algae growth. Iron is savenged pretty quickly by organisms ;I doubt much would hang around or survive in biologicaly reactive forms to make much differnce in an an oxic area of a deep sand bed.

Anecdotally:

I do think from my experience that moderate organic carbon dosing enhances microfauna and enhances the food web from the bottom up via the additional bacteria.

While the sand provides large amounts of surface area for bacteria to colonize and burrowing organisms to live in;how to get and keep enough of the bio turbulators and bio irrigators deep in a sand bed is ,however, enigmatic particularly over a long period of time; perhaps extra organics would help to sustain a useful population with lots of attention to managing a deep bed including replenishing some of the sand with a good source of live sand. and critters . The other side of that is the potential for anoxia and sulfide production.

I also think you can more easily get enough turbation and irrigation to deliver the necessary nutrients in a relatively shallow substrate without the worry of maintaining bioirrating and bioturbulating organisms, since the facultative heterotrophic bacteria will form hypoxic areas suitable for anaerobic activity and nitrate reduction to N2 in the first inch or less and even in their own mulm if there is enough oxygen and organic carbon,nitrogen and some phosphate flowing to them in the shallow sand or rock surfaces. .

Difussion as a movement force is weak and slow all by itself ;detritus may not settle deep as older beds tend to clog probably from bacterial biomass ;so many deep beds are relatively void of nutrients in the deeper areas unless they are successful in maintaining enough sifters and burrowers which is not very easy.

I keep a remote deep unlit sand bed with live rock on top and brisk flow with the idea of enhancing advective flow into the sand . It's been there a long time as an early inadequate effort to control nitrate in my heavily fed system. It is a good habitat for pods, sponges.filter feeders and some ploychaetes. If I were putting in a new one I'd use the same amount of sand but spread it out to provide a larger shallower surface area with a larger footprint and brisk flow over it.

 

[Khemul]

macroalgae uses phosphate, thats natural

The other thing about macroalgae in this subject is that it is sort of irrelevant to DSB's, since macro doesn't absorb through roots. Sea grasses and mangroves will absorb P out of the sandbed, but algae absorbs from the water column. Meaning that macroalgae is just as effective in a bare system as in a DSB system.

And it doesn't impact any of the clogging concerns, since the 'roots' of even the sand-dwelling macroalgaes don't go any further then the surface of the sandbed. They don't dig in at all like real roots. They stop once they grab onto something, since that is their purpose.

 

[tmz]

Many don't dig in ;some like bryopsis do even into rock, though.

Macro algae are relevant in a different aspect when kept over a sand bed, in as much as they put out exudate which is mostly refractory( doesn't degrade ) which can clog a sand bed . Personally, I prefer to grow macroalge ina bare bottom set up.
While they take up phosphate ,it's still there unless they are harvested.