how deep of sand bed?

[kelleyga36]

Setting up a new tank 36"by24"by25" 3 side starfire.Now how deep of sandbed should I have. In the current tank 36 gal bowfront. I have about a 3 inch sandbed. But I have a sand sifting goby and he tends to pile all of the sand in large piles. And since the gobys arrival 8 months ago I am always fighting nitrate problems 20ppm. I had 0ppm before the goby.I want to set this tank up in such a way as to avoid the nitrate problems.It will have a sump below it and about 100lbs+ live in it. Should I use course sand or fine? Deep or shallow?
Any input is welcome.
Thanks Kevin Kelley

 

[Wy Renegade]

Setting up a new tank 36"by24"by25" 3 side starfire.Now how deep of sandbed should I have. In the current tank 36 gal bowfront. I have about a 3 inch sandbed. But I have a sand sifting goby and he tends to pile all of the sand in large piles. And since the gobys arrival 8 months ago I am always fighting nitrate problems 20ppm. I had 0ppm before the goby.I want to set this tank up in such a way as to avoid the nitrate problems.It will have a sump below it and about 100lbs+ live in it. Should I use course sand or fine? Deep or shallow?
Any input is welcome.
Thanks Kevin Kelley

A properly set-up DSB consists of three distinct layers, each ranging from 1" to 2" or more in depth.

The Bottom Layer or Plenum: The bottom layer in a DSB can be set up in one of two ways; either a plenum or a layer of very course substrate. This bottom layer is the anaerobic portion of the DSB, and anaerobic bacteria, similar to those found living deep inside the pores of LR, are found here. These anaerobic bacteria complete the nitrogen cycle, by converting nitrates into harmless nitrogen gas. Hydrogen sulfide gas is also produced as a result of this conversion, creating slightly acidic conditions in this area. Generally this deadly hydrogen sulfide gas is broken down within the anaerobic area, however, if this deep layer is disturbed by the hobbiest or deep burrowing fish or invertes, this gas, the acidic water, as well as any trapped nutrients may be released causing the aquarium to "crash."

The Plenum
A plenum is created using an undergravel filter or eggcrate covered with a layer of plastic or fiberglass screen supported above the bare aquarium bottom by inert spacers such as PVC or plastic pipe. The plenum creates an open water space 1" to 2" inches deep.

Plenum for a remote DSB

Bottom of the Plenum

Course Substrate
In the event that a plenum is not used (and research has shown that there is no significant benefit to using or not using a plenum with DSBs), the bottom layer can consist of a 1" to 2" layer of course sand, CC gravel or crushed shell; regardless of the substrate used, the material should be course enough that the layer is very porous allowing bacteria to colonize and water to diffuse easily. Using aragonite sand, CC, or crushed shell also allows these substance to break down in the slightly acid conditions of this layer, and release calcium carbonate into the aquarium water at a slightly faster rate than normal. A layer of plastic or fiberglass screen should always be placed on top of the course substrate or the plenum. The purpose of the screen is to prevent deep burrowing fish or invertebrates from disturbing the bottom layer of the DSB, and releasing hydrogen sulfide gas, acidic water, or nutrients into the aquarium.

The Second Layer: The second layer should consist of a layer of aragonite sand, roughly 1" to 2" inches in depth with a particle size of about 2 to 3mm. Either "live sand" or dry aquarium sand can be used for this layer, if dry sand is used however, it should be seeded with true live sand (not the bagged live sand) aquired online or at your LFS, in order to introduce the desired microfauna and bacteria required to maintain the DSB long term. A second plastic or fiberglass screen may also be added at this point.

The Final Layer: The final layer should consist of an 1" to 2" of very fine sand with a particle size of 1mm or less. Some prefer to use "sugar sand" for this layer, and live "mud" is sometimes used for this final layer in some remote DSBs. Again, the introduction of desirable microfauna and bacteria is required.

Maintanence:
Contrary to popular belief, a DSB requires little direct mainanence by the hobbiest. Properly maintaining a DSB requires that the sandbed remain relatively undisturbed, although some raking of debris and syphoning the top inch of sand is not uncommon. DSBs function by the slow diffusion of water through the sandbed, and a diverse population of microfauna is required; the tiny worms, mollusks, and crustaceans that dwell within the sandbed are what keeps the water flowing through the bed. Additionally, a strong flow must be maintained across the surface of the sandbed at all times. Most of the microfauna that maintain the sandbed are filterfeeders, and a strong steady flow is required to provide them with a fresh supply of food. The flow should not be strong enough to move the sand itself, but should be enough to prevent the accumulation of debris. And finally, and most importantly, sand-sifters, such as sand-sifting fish (some species of gobies for example) and seastars quickly remove the biodiversity from a DSB and should generally be avoided, especially in a smaller aquarium.

DSBs are not recommended for aquariums smaller than a 20gal long and require the regular re-introduction of sand or mud-dwelling microfauna, usually accomplished by the addition of more true LS or LM.

Because of the inherint risk involved with a DSB, many prefer to set up a remote DSB as part of their sump/refugium system rather than establishin the DSB in their aquarium. These remote systems are typically set-up with a valve system so that if something goes wrong with the DSB it can be taken off-line.

Remote DSB

HTH

 

[Gimili the Great]

anthony calfo has an awesome write up in the front of his books on DSB and the different varies and pros and cons of each set up.

here are some links to some good info from anthony calfo
http://forum.marinedepot.com/Topic59558-13-1.aspx

http://forum.marinedepot.com/Topic22357-13-1.aspx

http://www.wetwebmedia.com/deepsandbeds.htm

 

[ahayes13]

i used fiji pink fine sand and love it. just fine enough to look nice but not too fine. and i have a shallow sand bed about 1 1/2 inches and love it. my last tank i had a deep sand bed and didnt like it. it held a lot of gunk and got dirty really fast. i prefer the shallower sand bed that i have now, it doesnt get as nasty and i have lesser nit. readings...

 

[ZOABOY]

3-5 inch in my sump.

 

[Gimili the Great]

also another thing about sand beds is you will have to eventually replenish it over time.

 

[Hypertek99]

I think a lot of people put sand in the display to what they like. And a deep sandbed in a refugium for better filtration.

 

[AZDesertRat]

3-5 inches is optimal for a fully functioning deep sand bed, if anything err on the deeper side. I have tried every method known to man and still keep coming back to a 5" DSB in the display tank. I love the natural look and all the critters it supports. I disagree with those who say change it out over time though, I give it a boost occasionally with a few cups of sand from trusted friends tanks but would never get rid of it.
No screens, plenums or mixed grain sizes, just 330 lbs of Southdown unrinsed so I kept the important fines and small grains.

 

[kelleyga36]

I think I am going to go with 1 inch or so in the display. Then 4-5 in the sump.

 

[Natclanwy]

I prefer deep sand beds, I am currently running a 4" deep silt sand bed. DSB can be very beneficial and are easy to maintain as long as you have Patience.

The biggest cause for failure with a DSB is the lack of Patience, and OCD. You have to have the Patience to allow the micro-fauna and your clean up crew to do there thing and maintain the sand bed and avoid the OCD desire to take things into your own hands and disturb the sand bed.

Someone mentioned plenums, plenums have some risks of their own and I really don't care for them. With a plenum there is a higher risk of contaminating the entire anaerobic region of the sand bed if the sand bed gets disturbed by a burrowing fish, the tank keeper, or a rock slide. There also is an increased risk of releasing toxic levels of H2S into the water if the sand bed is disturbed.

 

[Sikryd]

I think a lot of people put sand in the display to what they like. And a deep sandbed in a refugium for better filtration.

+1

 

[BluegrassReef]

would it be safe to say a DSB in the tank and the fuge would be better?

sorry I don't mean to hijack.

 

[AZDesertRat]

Unless your fuge has lots of surface area it does not do much good. The greater the area the more the benefit. I reserve my fuge for rock rubble and macroalgaes and keep the DSB in the display where I get the most bang for my buck.
If you want to find out everything you would ever want to know and then some on DSB's search for articles from Dr. Ron Shimek like found here on his website, he is the recognized authority. I was fortunate enough to have a member of my reef club who studied under him and she taught us all a great deal, even brought microscopes to meetings so we could look at the fauna and flora in the DSB. Amazing!