[naser]

just thinking nitrates stay low or gone with 2 inches of sand. why waste all that space in your tank with sand? i mean 5 or 6 inches is alot of room when your talking about a 24 inch tall tank. your wasting a half a foot of room were corals can sit. just for a huge clump of sand. i have less than 2 inches. allways had that same amount. nitrates are undetecable in my reef, always wondered why people go that extra 4 inches. ive read all the pro's that people write about just wondered if it was proven!

[cwa46]

What do you mean by proven? It is a better filter system than live rock or a trickle filter. If your bio-load does not get high enough to cause you a problem than it may not be for you. I don't get the idea of lost space though. You have given up 2" for sand already, so if you gave up 2" more than you will have a DSB. If your bio-load was high enough that you couldn't keep nitrates down, then the extra 2" would be a small price to pay.
There a lots of ways to keep reef animals and fauna. The most effective found so far is a DSB with algae export. You have to choose the one that best fits your needs and desires. Most people want to add more fish or corals and to do so requires more filtration. If you have a cat, you can get by with a Volkswagon. If you have horses, a truck and trailer is a necessity.

[This message has been edited by cwa46 (edited 05-10-2001).]

[36]

Like so many things in reefing, different folks have different results using the same method. Some have solved a problem with a DSB and some never have a problem. All systems are unique.

My sandbed averages about 2 1/2" deep. In some areas it is only 1" and in other areas close to 4". (I have some kind of sand critter that likes to make piles in certain areas.) I have a med/heavy tank load. My nitrates have always been zero. But I also have a semi-large amount of LR. If you have a DSB you can get by with a much smaller amount of LR, thus taking up less room.

[scubadude]

Originally posted by naser:
i have less than 2 inches. allways had that same amount. nitrates are undetecable in my reef, always wondered why people go that extra 4 inches.

Hi naser [img]/ubb/smile.gif[/img]

I think that systems can be stable w/ lower SB's and the DSB (if maintained properly) can be better, and is more for tanks with heavy loads (or just to be on the safe side) Well-Fed tanks is a very important issue I believe in DSB But there are many things that have to be taken into consideration when having a DSB the first and foremost important one is to make sure that you have enough life in it to take advantage of the "filter effect" worms IMO are the most vital part of the DSB they help stir the sand very slowly and process the trates at a steady rate. There are other important points to your DSB too such as grain size (HD southdown play sand, most effecient if accessible).
So IMO it boils down to the questions "Do you want to have alot of life in your system? and if so are you prepared to feed it heavy, if needed?" I understand exactly what you are talking about when you say "why waste that other 2-3" of depth when you dont need to" Its expensive real estate! HTH [img]/ubb/biggrin.gif[/img]

[ravenmore]

Hey Naser,

I'd pop over to reef central and run your question by Dr. Shimek (the deep sand bed guru). He has a forum there although he will be gone until sat. morning. Spasse might contribute - he's very knowledgeable on this subject also.

My sand bed is 4" and I plan to add to that. I read in one of Dr. Shimek's threads that he states sand beds can continue to benefit from depths increased up to 8". The idea was that anaerobic zones form in the deeper sand bed layers that help to filter out phosphates & nitrates. (you have caulerpa if I recall. That probably has a lot to do with the low nitrates). Light and oxygen can penetrate 2" of sand.

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I didn't do it. Nobody saw me do it. You can't prove anything.

Website

[Ninong]

Is it possible to maintain a reef aquarium without a sand bed? Yes.

Is it possible to maintain a reef aquarium with a 2" sand bed? Yes.

It is also possible to approach the construction of a reef aquarium with the goal of establishing a miniature reef ecosystem with the same energy and material flows as found in nature. What do we find at the top of the food chain on a coral reef? Fish... a LOT of fish. Much more than are found in temperate coastal ecosystems. So the productivity of a coral reef ecosystem must be very high.

Where does all this productivity start? It starts at the bottom. It starts with the life that resides in the sediments on the ocean floor. Not just microbial life but a lot of wormlike animals and microcrustaceans. We can duplicate this community in our aquariums if we provide appropriate sediments for survival of a diverse population of sand bed infauna. What would we gain from doing something like this? The byproducts of the biological activity of the sand bed life would provide protein (bacterioplankton, zooplankton, microzooplankton, the ciliates and multicellular small larvae of benthic animals, polychaete larvae, nauplii of copepods, etc.) to feed the rest of the aquarium's inhabitants.

The sand bed would also process a lot of the waste from the aquarium (detritus, mucus excreted by corals and Tridacna clams, DOM) as an energy source to feed the sand bed infauna. It is possible to establish a miniature ecosystem in a reef aquarium that will be relatively self-sustaining, if we provide the proper environment for the animals that produce and process the materials and energy that flow through the system. All we have to do is feed the aquarium and provide the pathways for efficient flow of energy and materials. And, if we were very, very wealthy, and could afford a very, very large aquarium, we wouldn't even have to feed it once it was fully established. Don't ask me how large, I have no idea.

One little statistic that I am fond of: The microbial population in the reef ecosystem uses about 70% of the total energy flow in its metabolism. (Sorokin 1995, Coral Reef Ecology, p. 390)

The best explanation of the importance of a properly functioning sand bed community in a reef aquarium that I have ever read is this talk by Dr. Ron Shimek on #reefs: http://www.reefs.org/library/talklog...ek_090698.html

Regards,

Ninong [img]/ubb/biggrin.gif[/img]

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Irrational Exuberance!

[SPasse]

Naser,

Ninong pretty much covered the subject.

I have been experimenting with DSB’s and plenums for about 10 years, and although I have had systems with shallower sand beds with no nitrate problems, lots of people have also cured “chronic” nitrate problems by going to a 6” DSB.

Some people have even had system with nitrates in the 5 to 10 ppm range that dropped to levels that were almost unreadable by just adding an additional 2” of sand to an already established 4” DSB.

Also, the bottom layer of a “deep” DSB seem to host processes where the pH drops to levels low enough for at least some dissolution of aragonite based sands.

The huge surface area of a deep fine DSB makes live rock use more of a aesthetic consideration than a practical one. Also this cuts way down on the amount of live rock that is needed for a given system. My 180 required only about 150 lbs. of Fiji live rock to create the area shown on my WEB page.

So even though I will be the first to admit that a 6” DSB is a lot to look at, I consider it to be one of the most important “cornerstones” of a reef tank.

Regards,

Scott

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The definition of an expert is a washed-up drip under pressure.
You can see my reeftank at http://www.homestead.com/spasse/

[naser]

it wasnt to argue i was just stating what i thought. i have a pretty high bioload for those that say its for a pretty highs bio load. just saying my peice. i relize everyones pro's to a dsb i was just stating that you can do it without the 5 or 6 inches that everyone says you must use.

[naser]

i also have over 100 pounds of liverock in my 55 gallon. so that might be helping me cause!

[NCF]

Excelent thread,

I just wanted to add that LR still serves more than just an aesthetic purpose. It is the major microfauna adition we place in our tanks.

Norberto.

[Ninong]

Excellent point Norberto, live rock is very beneficial to the system. Only reason I didn't mention it was because it's importance wasn't questioned in the topic title.

Ninong [img]/ubb/biggrin.gif[/img]

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Irrational Exuberance!

[SPasse]

NCF,

I just re-read my post, and what I should have said is that the amount of live rock in a system with a DSB is not as much of an issue.

Scott

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The definition of an expert is a washed-up drip under pressure.
You can see my reeftank at http://www.homestead.com/spasse/

[chromis]

Deep sand beds are a must for anemones, clams, etc.

[Ninong]

You can certainly maintain a reef aquarium with a 2" sand bed and live rock; it's been done for years now. And a 2" fine particle sand bed will provide some denitrification. According to Dr. Shimek, the aerobic layer in most reef aquariums is the top 1/2" to 1" of the sand bed (pretty much what olgakurt just said), and the area of reduced oxygen begins just below that. So while you would usually have anaerobic conditions 1-1/2" below the surface, you would have even better anaerobic conditions 2-1/2" below the surface; and if you want to see any phosphate or sulphate reduction in your sand bed, you probably need 5 inches minimum.

A sand bed of at least 4" depth will provide much more denitrification and much more biodiversity than one of only 2" depth, allowing for the processing of much more energy (food) through the system. It is important for anyone considering a deep sand bed (4" or more) to add the appropriate polychaete worms and other sand bed infauna to properly maintain such a sand bed depth. Even though you will get some migration of fauna from live rock to the sand bed, it is not sufficient because it is the wrong kind.

So it is not really an argument of which is right and which is wrong. Maintaining a reef aquarium with a deep sand bed is another method that many hobbyists have adopted as a way of constructing a more natural ecosystem.

Ninong [img]/ubb/biggrin.gif[/img]

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Irrational Exuberance!

[naser]

why are dsb a must for clams? ive got a couple clams myself. and no dsb.

[Ninong]

I believe what chromis means is that a deep sand bed would provide the bacterioplankton and microzooplankton that Tridacna clams filter out of the water. Mature Tridacnids probably get about 80% of their nutrition from their algal symbionts but the rest comes from filtering; juvenile clams rely on filtering for their energy requirements more than mature clams.

Ninong [img]/ubb/biggrin.gif[/img]

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Irrational Exuberance!

[chromis]

Yeah, and the species that live in the sand like to dig/wedge foot down into the sand. Same w/anemones. Although clams could probably live w/less then anemones, they just need the nutrients, bacterioplankton etc provided by the deep sand bed.
Andrew

[Ironreef]

fwiw with a deep sandbed maybe 4" you can use less lr and accually have room for fish to swim and corals to grow. I don't like the reef wall look myself. and corals get big