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

[BriMc]

Dsb

Dsb

My experience with DSB tanks,

1987 to 94 - 75 gal tank 5" dSB , no issues, no losses. Broke down tank to move. 80 watts of light, DLS wet dry filter, limewood airstone square protein filter, Medium coarse crushed coral used as a substrate, Couple of pieces of live rock and tons of dead coral skeletons.

1994 to 01 - 75 gallon 5" DSB, no issues, no losses, Broke down tank to move.
384 watts from Power compacts, chunks of corall media in the wet dry filter in place of DLS materials, Protein skimmer changed to Red sea berlin skimmer, and chiller. Live sand from Tampa bay saltwater, and Live rock from the same.

2003 to present - 29 gal tank with 3.5" DSB, 26 gallon sump packed with live rock no sand, and a Med hob Refugium with 3" of sand and chaeto, 156 watts of t-5 lighting, Nac6a Skimmer, Chiller. Sand is Bio-Activ Live Aragonite fine and live rock is Marco rock seeded with Florida gulf live rock.

Everybody sitting down??? Water changes, yeah once every two or three months, I guess you could say are done by replenishing make up water lost from evaporation and protein skimmer waste. When I do water changes I do vacuum part of the sand bed or the entire refugium but I do not replace the sand. Tests, yeah Aquatronica monitors my PH, salinity, and temp. Once every few months I check Ammonia, nitrites, and nitrates. Additives I add are BRS three part system a few ML's every other day, and once every two weeks I add two caps of reef plus.

I have never had an issue with any of the DSB's an any of my tanks most issues I have had have been my own mistakes with over feeding or poor light maintenance resulting in hair algae issues which are usually quickly resolved.
All corals and fish that were in the tank since the beginning are still here with no losses and a few more have been added. Anemones split regularly, Frilly mushrooms have multiplied, Acans, Hammers, frogspawn, and candy cane corals have been and are growing new heads constantly.

Anything scientific? nope, I just know what has worked for me in the past and what is working for me now.

 

[tmz]

I kept a display tank with a 4.5 inch inch sand bed for abut 7 years with no issues;(many report success for years when using them) but I eventually removed it as NO3 and PO4 began to climb.

This is a recent post of mine from another related thread which may be of interest:


Good luck and thanks for the report.
FWIW,(vodka and vinegar) organic carbon dosing do culture naturally occurring bacteria in my tanks . I can see them in areas like the canister filter I use for running gac. If I dose too much they show up in other areas too. With heavy feeding ,NO3 holds around 0.2ppm or less per Salifert and has done so for over 5 years. I think based on what I've read the bacteria encouraged by the acetate take the N from ammonia directly ,assimilate some from NO3; perhaps, aiding anaerobic NO3 reduction as well.

I have a remote deep bed similar to yours. It didn't reduce NO3 in any measurable way ;after months the NO3 stuck around 50ppm . I think some facultative activity is occurring in the top inch or so,as nutrients are available at that depth, though but most of the sand is just inert. The problem with it isn't the biology ,per se, but more the physics. Not enough nutrients( C,N and P) move into the deeper areas. There is no force to move them there in significant quantity;diffusion is very weak and the advection from changes in water pressure under the live rock isn't adding enough upwelling and consequent downward flow to make a big enough difference. Sprung and Delbeek,Reef Aqaurium Vol 3, provide a a nice discussion of the fluid mechanics involved ;pgs 261 to 267. Infauna could help move things around and down but I don't know how to keep enough going in a deep sand bed to make it work well.

Here is the thread link:


http://www.reefcentral.com/forums/showthread.php?t=2358448

 

[BriMc]

Hi Tom

What are you running for a sand bed now?

Brian

 

[S2minute]

In the 150 where i keep my DSB, the LR is suspended above the DSB. I have not added any new LR in a long time nor have i added any "pod" packs. Yet, i can witness that the infauna are thriving. When i remove some of the black plactic shielding the DSB from light or if i go to the back side of the cryptic zone tank i can see all the tubes extending 3+" inches below. What i cannot see is accumulated detritus on the surface. I've never had an N03 reading even remotely close to 50 ppm except after the 3 weeks it took for the system to cycle. In fact, the highest reading I've ever had was 5 ppm. Dr. Ron Shimek, Sand Bed Secrets, The Common-Sense Way to Biological Filtration, is a small booklet focusing on the mechanics of DSB construction.
I've stopped using ROX .08 on a regular basis. Instead i tried using Bio-pellets again. However, for my system,(400+ gals),i use very,very little in a phosban reactor. Just a small fistful of it. Within 3 days i witnessed everything reacting better and that's with just a tiny amount. I still have readings for NO3 and PO4 but they are WELL within acceptable limits and stay at or near that level. The only idea i was considering on doing again was what TMZ mentioned about the use of a filter sock. He uses it only during maint. which i think is a good idea because it permits a more natural flow BUT, i use a 36" 200 micron filter sock and it gets dirty to the point of overflowing after just approx 48 hours of use and i change it. I'm nervous about just letting all the stuff settle in the sump and sit till water change time. I'm thoroughly convinced my DSB is adding to the diversity and overall health of my system and that if you begin with the right materials and apply proper husbandry a properly constructed DSB can last.....

 

[S2minute]

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

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

Hi Tom

What are you running for a sand bed now?

Brian

I use South Down Play sand that used to be carried by Home Depot. They may still sell it but under a different name. I bought 1200 lb of it.

 

[tmz]

Hi Tom

What are you running for a sand bed now?

Brian

From post my post #257.


I put it in years ago(7 inches deep by 36 in x 24 inches to reduce NO3 ;it didn't make any perceptible difference.
After months of waiting , ultimately, I used a sulfur denitrator to reduce them from the 50ppm to 80ppm range to near zero in two weeks .I took the denitrator off line when nitrate was dropped about 5 years ago and maintain low levels(0.2ppm or so) with organic carbon dosing.
I never removed the remote deep sand bed.
If nothing else it gives pods somewhere to hang out and provides extra surface area for bacteria to colonize at least in the top half inch or so . Extra live rock sits on top of it to aid advective flow into the sand a little It serves as an ambient light section of a cryptic refugium arrangement ,now; it's fed by a drain from a darkened section. If I were to redesign it, I'd put in a shallow bed with a longer footprint for water to flow over.

I also keep puddles of deeper sand( 3 to 4 inches ) in some of my display tanks for animals that need it mostly some of my wrasses.
As for maintenance I just puff up any detitus that builds on the surface every couple of months using a filter sock on the drain when doing so.

 

[tmz]

I've never had an N03 reading even remotely close to 50 ppm except after the 3 weeks it took for the system to cycle.

Good for you. If you are happy with it don't change it.
I'm very skeptical the 5ppm nitrate level is attributable to the deep remote sand bed with suspended live rock. Inany case 5ppm is significantly more than nsw which is around 0.2ppm . The nitrate level in any tank is likely due to the age of the tank feeding levels ,other variables in the tank and husbandry efforts as well as the organic carbon dosing in your case.

The sand bed with brisk flow will do some denitrification in the upper 1/2 inch or so. Obstructions on the bed create a drop in pressure with upwelling and consequent downward flow (advective flow) under the footprint of the obstuction. This helps get some nutrients to the bacteria. Suspending it obviates this effect.
Running rox 8 or another quality gac won't add nitrate. Can't understand the reference to stopping it in this context..

Dr. Ron Shimek, Sand Bed Secrets, The Common-Sense Way to Biological Filtration, is a small booklet focusing on the mechanics of DSB construction.

There is no accounting for the nature of the bacteria involved in denitrification in those early efforts as I have read many of Dr Shimek's fine works on sand beds and other topics.

 

[S2minute]

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

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

"I'm very skeptical the 5ppm nitrate level is attributable to the deep remote sand bed with suspended live rock. Inany case 5ppm is significantly more than nsw which is around 0.2ppm . The nitrate level in any tank is likely due to the age of the tank feeding levels ,other variables in the tank and husbandry efforts as well as the organic carbon dosing in your case."

The sand bed with brisk flow will do some denitrification in the upper 1/2 inch or so. Obstructions on the bed create a drop in pressure with upwelling and consequent downward flow (advective flow) under the footprint of the obstuction. This helps get some nutrients to the bacteria. Suspending it obviates this effect.
Running rox 8 or another quality gac won't add nitrate. Can't understand the reference to stopping it in this context.. "

I never said 5ppm nitrate is attributable to the DSB. I only mentioned that other than initial cycle, my No3 has never been even remotely close to 50 ppm. That the highest it's ever been was 5ppm since. I have to consistently use the low scale to get No3 readings....which avg. 0.2 ppm.

Your right, there is no reference to me stopping rox .08 and because of adding nitrate. I only wanted to add that i stopped it and started using a tiny amount of bio pellets. Which was a tad off topic but so what .

I've read many of Dr. Shimeks works as well. In the book i mention, his work is sound and makes sense. I applied it correctly and have had great success as a result. I have also incorporated ideas from Steve Tyrees CMAT and Captive Ocean Series with the knowledge i gained from Dr Shimeks works on DSBs and have gotten great results. There is no one author or hobbyist who is the ultimate authority concerning this hobby and everyones system is different. I try something and see if my system benefits from it. In this case with DSBs i'm confident that it did...in my system.

 

[tmz]

There is no one author or hobbyist who is the ultimate authority concerning this hobby and everyones system is different.

That is true. As I said if you are happy with your system don't change it.

My interest in not in whether deep beds are good or bad in any given system ;they are inherently neither ,imo. Although , I personally see little benefit in a deep remote bed beyond the first inch or so.
Understanding more about what sand beds can and can't be expected to do in terms of nutrient control as well as what they might do in terms of anoxia and the release of harmful materials as they age is a more informative line of inquiry to enable readers to make informed decisions about their choices for their aquariums.
To be clear; it is my opinion that a shallow bed with more footprint exposed to flow or alternative surface area solutions for bacterial colonization are more efficient in denitrification than deep sand given the nature of the facultative heterotrophic nature of denitrifying bacteria and the fluid dynamics in play.

Regarding the gac;consider that when using an organic carbon source like bio pellets organic buildup can be a concern ;gac exports organics. You can certainly bring it into the discussion but I didn't understand any implication for the dsb you might have been making. Apparently , there was none.

I don't enjoy questioning other's posts but when it appears a particular method is being put forth as a model ;critique of the assumptions therein should be expected and is sometimes necessary for a rigorous informative discussion. Asking: how do you know?why do you think so? or how does that work ? are always good and fair questions ,imo.

 

[Dog boy Dave]

I have used remote DSB as components of my nutrient export routine in this system for 7 years now and the sand in one of the remote sand beds was 6 or 7 years old when I moved it to this system. So some of my sand is well over ten years old. I actively manage my sandbeds and react when I see nutrients begin to build up. I keep them predator free. I feed this portion of my system very heavy and my fish are big.

 

[swcc]

I have used remote DSB as components of my nutrient export routine in this system for 7 years now and the sand in one of the remote sand beds was 6 or 7 years old when I moved it to this system. So some of my sand is well over ten years old. I actively manage my sandbeds and react when I see nutrients begin to build up. I keep them predator free. I feed this portion of my system very heavy and my fish are big.

your experience and methodology would be greatly appreciated... best way to learn is from the success of others...please.... elaborate

 

[Buran]

Interesting discussion :reading:

My experience: I have a 4-year old DSB, measuring 0.00 mg/l PO4 with photometer equipment and some month ago I tried to measure PO4 within the layers of sand up to bottom and found always zero.
The same procedure for NO3 gave me a peak of 3-4 mg/l in the first centimeters of sand.
Of course, that does not give infos about organic waste but in general I don't think that DSB is so dangerous due to phosphate

 

[sellmecorals]

Only dangerous if you don't know what you're doing.

 

[Dog boy Dave]

your experience and methodology would be greatly appreciated... best way to learn is from the success of others...please.... elaborate

Pretty much what TZ said although i run lights on top of my sand and my lagoon has anemones, mangroves, lots of caulerpa and quite a few LPS and other lagoon type animals in it. I do maintain several hundred pounds of live rock in darker zones, both high and low current. I observe different animals including lots of sponges growing in the dark areas even though all of the remote sumps are maintained predator free. I do not run filter socks but have considered them occasionally as I have lots of debris build up in my settling areas. Total system volume is approximately 800 gallons with 325 in the main SPS display. I never measured phosphates in the past but the other night they were in excess of 6 ppm. I recently cycled some rocks for a friend and they were much dirtier than i knew when he asked me to keep them for him. I haven't measured since that reading but my observations of coral appearance and caulerpa activity would suggest that it is dropping. I do not consider sandbeds the end all for extreme filtration systems. I also use settling areas, darks zones with rock, aggressive algae and mangrove cultivation and harvest as well as heavy skimming. I have large fish and I feed heavy. Sand beds properly constructed and maintained are just one more tool in our arsenal of tools to export nutrients, phosphates mostly. As far the question of them being dangerous, a properly designed and maintained remote sand bed is not dangerous. However, half hearted attempts to put sand or gravel in your main display can and often do contribute to serious long term sometimes catastrophic issues as the system ages.

 

[Fredfish]

Pretty much what TZ said although i run lights on top of my sand and my lagoon has anemones, mangroves, lots of caulerpa and quite a few LPS and other lagoon type animals in it. I do maintain several hundred pounds of live rock in darker zones, both high and low current. I observe different animals including lots of sponges growing in the dark areas even though all of the remote sumps are maintained predator free. I do not run filter socks but have considered them occasionally as I have lots of debris build up in my settling areas. Total system volume is approximately 800 gallons with 325 in the main SPS display...

This is the type of system setup I've always wanted to try, but never had the space, time and money to do well.

You wrote that you actively manage your sandbed systems. What do you do to maintain them?

 

[crissie]

Okay, so thus far I have only read the first 5 pages (will read the rest shortly) but I have a question, why is a DSB such a controversial issue? Surely it's little more than a case of "each to their own", so to speak?!

 

[power boat jim]

Okay, so thus far I have only read the first 5 pages (will read the rest shortly) but I have a question, why is a DSB such a controversial issue? Surely it's little more than a case of "each to their own", so to speak?!

Because some attribute the reason at least in part for their aquaruim being successful to the presence of a DSB. Others have traced the demise of their aquarum directly to the DSB.

 

[tmz]

For a long time they were viewed as necessary for nitrate control by many and advocated strongly by noted authors in the hobby. A backlash to that position evolved over time as some with older beds had difficulty and some studies argued against their efficiency in nutrient reduction. Its pretty clear now that the bacteria performing nitrate reduction don't need deep sand or hypoxic areas to thrive .The earlier underlying assumption was that that they were obligate anaerobes, requiring oxygen free areas that a deep sand bed afforded. Nonetheless,the backlash as is usually the case sometimes overstates the case against using them for other reasons as one may choose to do.

 

[crissie]

It's all a bit OTT to me!

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

 

[tmz]

It's a choice depends on the animals you wish to keep(some need deep sand) and the aesthetics you want.