Deep Sand Bed -- Anatomy & Terminology

[tmz]

A shallow bed does just fine for life and denitrification and a beachy look ,ime. the sand is only surface area .The bacteria that perform denitrification do fine in very shallow beds or rock surfaces. Bare bottom tanks work well too.

Deeper sections are useful for animals that need them, like certain wrasses , anemones, shrimp , jawfish ,gobies, etc)

Cyano doesn't consume N2 gas. Many types of cyano can tie hydrogen to it thus putting it back in the food chain. There is plenty of it around as the athmosphere is over 70% nitrogen.

 

[Paul B]

Why would someone opt for a DSB with its risks if macro algae can give you the same pros without the cons?

Most people don't keep a tank long enough to have problems.

DSBs can work. People have done them, and some over decades.

Does anyone here have a DSB for more than one decade? How about 2 decades?
How many here had DSBs fail before 10 years?

 

[jerkyjunky]

Most people don't keep a tank long enough to have problems.



Does anyone here have a DSB for more than one decade? How about 2 decades?
How many here had DSBs fail before 10 years?

Didn't EC have one for 20? He likes to break the mold it seems. I guess the point is that I'm not doubting they can work, but are there actually any advantages to say a huge pile of macro algae in a fuge? Also, can one of you more experienced chaps tell me how much life will be visible in a SSB in comparison to a DSB?

 

[tmz]

Macro alge refguia need a large foot print to allow for growth; good lighting and pruning. IME they work best over a bare bottom. Otherwise exudate and other detritus builds up on or in the sand or rubble under them. The macrolgae takes up phosphate, nitrate and CO2 and produces O2 and organiic carbon.They work fine but need to be of sustantial size relative t othe tank to make a big dent in NO3 and /or PO4. Many people use both a sand bed and a macroalgae fuge. Note teh dsb won't do anything for PO4.

I ran a dsb on a display tank for over 7yrs. , I run a 7 inch remote deep sand bed now; it down't do much in terms of denitrification but does host some pods. . 5 of my tanks have shallow beds. Just about the same amount of life is visible ,ie mostly worms feather dusters and pods.

 

[Paul B]

Also, can one of you more experienced chaps tell me how much life will be visible in a SSB in comparison to a DSB

I don't have a DSB or a SSB but I do have about 2" of gravel. It is full of amphipods all the way to the bottom of the tank and if I disturb it a little, it is also full of brittle stars.
A DSB would only have life at the very top where there is some oxygen

 

[10reefman]

should I place rocks first then dsb around the rock or rocks on top of sand? thanks

 

[tmz]

Don't bury live rock. the organics in it will fuel bacteria to a point where they use all the oxygen in the area setting the stage for sufate reducing bacteria and the sulfides and toxic hydrogen gas they produce.

 

[reefingnoob]

Tagging along

 

[DOGGIE750]

Wow...
To play it safe.....do a Remote DSB?

 

[coralsnaked]

Deep sandbeds IMHO and IME should be limited to the ocean! HA:eek1:

That is to say they had their place and have become dinosaurs. Really their value in the Aquaria forumn is very limited compared to other NO3 reducing techniques. Definitny not asteically appealing in the 21st century. Therefore w/ their potential to create problems they should be limited to refugiums and buckets that can be taken off line and completely eliminated when needed.

 

[tmz]

Remote beds don't do much at all for denitrification beyond the first inch or less of depth. There isn't sufficent force via difusion alone to move nutrients down to sustain the bacteria ( they need nitrogen, phosphate ,organic carbon, and others. Deep sand areas are useful for certain animals that need them to bury or buurow in, such as leopoard and other burying wrasses , jawfish, certain anemones , etc.

 

[EdKruzel]

NO3 reduction is only the tip of the iceberg when referencing a DSB. Most hobbyists don't have the experience or knowledge to properly maintain a tank with a DSB and even fewer have the discipline or patience.

While a DSB greatly increases the amount of a bioload that can be supported, ironically it also great reduces the variety of species that can be kept.

Very common creatures in this hobby such as hermits, bumblebee snails, many shrimp and any fish that digs or burrows can easily decimate a healthy DSB. Improperly maintained a DSB is a nightmare, quickly becoming a nutrient dump and an eyesore. Properly maintained, you'll have as close to an authentic slice of the ocean possible in a glass cage.

 

[DOGGIE750]

Remote beds don't do much at all for denitrification beyond the first inch or less of depth. There isn't sufficent force via difusion alone to move nutrients down to sustain the bacteria ( they need nitrogen, phosphate ,organic carbon, and others. Deep sand areas are useful for certain animals that need them to bury or buurow in, such as leopoard and other burying wrasses , jawfish, certain anemones , etc.

As noted by others, there's a possibility of failure so I would like to check in with the SME if my design, planning stage, is sufficient.

Option1: 400 reef with 2-3" SSB and 120 Fish with 5-6"DSB, both tanks integrated sump

Option2: vice versa so if push come to shove, 120 gal is manageable.

Pls advise SMEs which option should I proceed. Thank you!

 

[Reefer54]

I have read no less than 20 lengthy threads about DSB and RDSB, a book, and currently have some 8 inches in the majority of my sump (75g sump, no sand in the return chamber)). I did have the same 8 inches in my DT, but a goby my kids lured my wife into has turned that into a 11 inch side and 2 inch side. funny, but what a pain, and just about impossible to properly maintain. However, Nitrate is not a real problem....minimal readings

I am moving all LR and livestock to a new 143g cube, might put 40 or 60 lbs of arag in the DT. very bare sump this time too (have 200+ lbs LR in the current sump, and i am tired of a dirty looking sump, i want it clean). But i intend on implementing a Remote Deep Sand Bed. I want to use a 27 gallon brute tub, with lid, filled with both sand and LR. a RDSBWLR if you will.

My question pertaining to the RDSB is twofold. Calfo says to use a minimum 10 inches of sand when using a bucket. the OP of this thread says not to go beyond 6 in. Calfo's method includes just a few inches of water above the sand. My method would include rock and more like a foot of water above the top of the sand.

Q1. What is the importance of how much depth of water is over the sandbed; i feel like it would be regarding the advection\convection efficiency, but cant wrap my head around how it would really matter if enough flow through the container is implemented (27 gallon brute with 1500gph is my plan).

Q2. and this relies on Q1. I intend on filling this Brute with LR ( i have about 350 lbs) and i can not find very much info on Cryptic RDSB. With the rock, my water must be higher than the Calfo suggestion. Has anyone read or seen this in action.Ideally, i could remove and continue to use the rock as i need to replace the RDSB in a couple years. please comment, critique....etc.

and FWIW, clearly i am a total believer in the DSB.

 

[tmz]

I've had a similar remote sand bed with live rock running for about 6 years.
The depth of the sand is about 7 inches ;the water flowing above it is about 10 inches deep to cover the live rock. The advection depth into the sand relates to the the height of the obstruction to current,ie ,the rock as well as the speed of the current. IIRC, the notion of shallower water did not include live rock or other obstructions and assumed shallower water would allow for less detritus to settle on the sand


That set up is fed from a "cryptic refugium" ,a lidded brute garbage packed with extra live rock. It is fed with drain water at the bottom which exits the top and moves on to the sand bed with live rock which is kept in ambient light before going on to the sump. Sort of a two stage dark and ambient light cryptic refugium with a remote deep sand bed built in.

 

[Sisterlimonpot]

Good to see this thread still going strong,

Tom, I'm glad to see you still maintaining the thread. Your vast knowledge in the biology of this hobby is greatly appreciated.

 

[Aquarist007]

I used to run a similar setup to Toms but the deep sand bed screwed up around the seven year mark. Now I just run a 60 gal with about 250 lbs of live rock. With carbon dosing so easy to do now I just don't see the value of running a deep sand bed in the tank or remotely
You need to keep close track of your nitrates and phosphates for a while and learn what is best for your system

 

[Sisterlimonpot]

That is exactly what I do... I still pump vodka into my tank and seem to have great results...

 

[tzylak]

Reefer54,
I'm only 6 months into DSB but fascinated by it and here is my understanding:
You need the medium to be 2-6 inches deep to get the anoxic going. -The finer the media the shallower the requirement. I have 2" of arrago and 4" of play sand.
If I get 100% of action out of my 6" depth then I might get 150% out of 8" and maybe 160% out of 10". -The increase is not linear and the effective increase drops down to near 0 with anything over 14".
So, for the BRUTE container I'd go no deeper than that.
#1 Regarding the water height, 1" of depth would suffice to maintain the action. However, I'd fill the BRUTE just about full to maximize the water volume which = to maximizing the tank stability.
#2 Yes, fill it with rock. So what that the flow rate slows down to near zero? Yes, the detritus will settle, the bacteria will convert it to NO3 and the DSB will take care of that NO3. IMO the fast flow rate requirement for this application is erroneous.
With respect of the prognosis of the 2-7 year tank crash, I installed a plenum with tubes going down to the bottom. After a year or two I'm planning to take a quarterly (monthly?) sample of the anoxic water and do a sniff test. If anything smells, I'll siphon out the water from the bottom (flush out the DSB) without affecting the DT.
Here is my setup: www.dropbox.com/s/4rzehzt3k3e8tds/150208 Aquarium.wmv?dl=0
Consider installing the probe tubes in your Brute for your peace of mind.
Have fun!!!

 

[Reefer54]

Thanks all for the responses, you have confirmed what i believed to be true from the 2 tanks which i have run DSB in and the info i have gathered. The remote bed is so much more appealing as i will not have to monitor it (so to speak)

T-lak;
"With respect of the prognosis of the 2-7 year tank crash, I installed a plenum with tubes going down to the bottom. After a year or two I'm planning to take a quarterly (monthly?) sample of the anoxic water and do a sniff test. If anything smells, I'll siphon out the water from the bottom (flush out the DSB) without affecting the DT."
Tubes into the plenum would not occur to me as anything but a risk. i looked into plenums with great length in the past, and the idea is awesome, but without proper care, they carry as much risk as a mistreated DSB. Wouldnt you be concerned of the advection possibilities by a tube which is directly connected to the anoxic layer.....i mean, the idea of a plenum is not to mess with that layer. If the plenum was remote and quickly removable, i get it, but if it is integral to your sump or DT....i would feel like i was dancing with flares at a gas station. But you have me curious how that works for you.

But back to me (lol), one critical measure of the RDSB is to not allow detritus to enter the chamber, or, to be carried away with the current before settling. With this in mind, i added a 100 micron poly felt tray which partitions the chamber my pump dedicated to the RDSB would be in (as well as two 200 micron socks at drain,skimmer, LR and Chaeto in previous chambers). The rock in a rdsb in theory can only provide more buffer, biodiversity, and added water volume, but is not worth it if it creates a compost pile (forget the sink). Combined with a diffuser according to Calfo's specs, i feel pretty confident i will be able to control the vast majority of TDS entering the system.

I also appreciate the reiteration of measurable sand depths and grain sise relevance....numbers which are measurable to a degree are not frequent enough here, especially when newbies have specific questions. (head loss is a perfect example, explaining that never gets dull,lol)

"Consider installing the probe tubes in your Brute for your peace of mind." i honestly believe that not doing this is in my best interest. A system like this must be implemented with the self confidence and beliefs that what i am doing and how i am doing it, is correct. My LR question was the one area i was uncertain about in regards to water depth and compatibility, but notice my flow rate.....


thanks again everybody.