DSB and your marine tank!

[Achilles Tang]

Ok... this is gonna address some concerns abt DSBs...

Taken from Dr Ron's forum:

How do you prevent hydrogen sulfide buildups in a DSB?

You don't, cause it normally doesn't build up. Sulfides are produced in anaerobic condtions, but they are oxidized in aerobic conditions exceptionally rapidly, and they also go to bind toxic trace metals. The only way hydrogen sulfide can build up to anything like lethal levels would be to bury a large piece of flesh at the bottom of the tank, and enclose it there until it had rotted away. This simply doesn't happen in reef tanks.

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quote:

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When a lot of echinoderms spawn they release chemicals that are toxic to fishes, or they release eggs that are poisonous to fishes.

If hydrogen sulfide poisoned your tank, 1) it would not be selective- this stuff is more toxic on a weight per weight basis than cyanide. The tank would be dead, not just one fish. Secondly the room would stink - really stink of rotten eggs. In general, one cannot build up enough of the gas in a tank to poison anything.

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[Achilles Tang]

Yes, in all local context, 6" DSB commonly refers to 6" of #1 sand as this is commonly graded in LFS.

Because of the 6" deep DSB of oolithic grain size recommended by Dr Ron Shimek, our #1 sand would barely sufficient at the same 5 to 6". Perhaps at #1 size, it would be properly functioning at 7" to 8"?

So the difference between Wei's recommendation for a 4" DSB and a 6" DSB is quite major. Not having that extra 2" of depth could reduce efficiency in terms of nitrate reduction as 4" of #1 sand could allow more aerobic bacteria as oxygen diffusion is much easier due to the larger grain size.

I know that is impossible knowing how deep our tanks are... but IMO, as the sand compacts over time, less oxygen would be following through and nitrification would happen due to it.

IMO, DSBs are like LR which in their inner core, anaerobic bacteria would be present to process nitrates. It works in Berlin systems where you require a lot of LR for this to work. With DSBs, sandbeds are much more efficient at processing nitrates... it can be treated like a big piece of LR (IMO, small LRs do not process nitrates efficiently... only bigger ones do. Logic dictates this).

As for Wei's concern abt sand clumping, if there is not enough sandbed fauna, there is not enough sandbed fauna. 4" or 6" or 8".... it will all still clump if conditions are right.

As for sandbed fauna.... these can be encouraged by building little 'pod piles', basically stacking some small pieces of LR together so they have shelter for predators where they can grow and hide. Introducing new pieces of LR or macroalgae will often repopulate the sandbed and rocks.

A sandbed does not need sand fauna to be properly functional... it needs bacteria. The sand fauna is there for 'maintenance'. Sand fauna does not process nitrates or nitrites... it's bacteria that does the job.

A DSB 'eats' voraciously. You will hear of people 'feeding' DSBs. Why? Because DSBs can 'starve'. DSBs allow people to stock more as a tank with DSB process nutrients faster than a tank without one (or a poorly setup one like 1" or 3" - not here, not there).

Using sea cukes don't eat detritus fast enough, whereas DSBs process them faster.

That is why DSBs are capable of reducing nitrites and nitrates to almost undetectable levels and why people with shallow sandbeds, coarse sandbeds and canister filters can't seem to maintain low levels without a lot of work.

I can't see why Wei doesn't advocate DSBs, or at least one more than 1" or 4" (bearing in mind we use #1 sand), with all the benefits like high nutrient-reducing capabilities, low maintenance, micro-fauna friendly environment that a properly setup DSB or Plenum system brings.

[Wei]

?????

I mean 1" in main tank for decor, 4" in sump for refugium in my previous post. I suggest Onghm to have his primary key filtration be in the refugium. But this is my personal opinion as I have stated above.

As for Wei's concern abt sand clumping, if there is not enough sandbed fauna, there is not enough sandbed fauna. 4" or 6" or 8".... it will all still clump if conditions are right.

Thats why we need to prevent sand clumping to min. If theres not enough live to prevent clumping, with a 6 or 10" bed, it will eventually clump to one & become useless. If sand clumping happens from below up, the functioning depth will become thinner as well.

It is common sense that bacteria is the one that breakdwn NO3. The pt I am hightlighting is the live needed to prevent clumping. Having a small pile of rocks to grow pods might work but think again. how deep can they dig & far can they go. Most likely, one will just be preventing sand clumping at that particular spot of the tank. I dun think one will havve pods pile all over their tank, they would prefer nice aquascape rockwork & stuff. For a DSB to function properly, having maximium surface area is needed. Having so many rock pile?

Without the live, all the food/detritus that cannot be process will eventually sink dwn to the sandbed. without the critters to eat & process them, one will get nutrient overload overtime.

IMO, DSBs are like LR which in their inner core, anaerobic bacteria would be present to process nitrates. It works in Berlin systems where you require a lot of LR for this to work. With DSBs, sandbeds are much more efficient at processing nitrates... it can be treated like a big piece of LR (IMO, small LRs do not process nitrates efficiently... only bigger ones do. Logic dictates this).

When sand clump together, its not like rocks with small holes & tunnel within. Its like a solid piece of plated rock. I have SEEN & help a friend of my to chisel & break the clump sand so that he can restart. If it clumps and function like a large LR, then I will also go for it. but its not going to happen. Might be due to the presure or compression, the clumped sand will compress into something like a plated rock with hardly any hole. Its simple, when u study geo where u learn about the layers below the earth. They are compressed.

I can't see why Wei doesn't advocate DSBs, or at least one more than 1" or 4" (bearing in mind we use #1 sand), with all the benefits like high nutrient-reducing capabilities, low maintenance, micro-fauna friendly environment that a properly setup DSB or Plenum system brings.

??? I have always recommend pple to go for DSB, of course, 4" is enough with c-1 sand. Plenum 5" cos the additional height of the gravel plate. The benefits of a DSB is like a common knowledge to pple already using them. What I want to empasize on is how important one is to have a LIVE DSB, maintaining them(not crashing after 2-3 yrs which happen to many pple.) and getting a fully functional sandbed.

For wat I see now, going for 4" or more than 4" is like going ard circles. Its just wat one believe more in. Wat we need to concentrate on is how to maintain the ecosystem within the sandbed. 4" or 20", without sufficent critter in DSB, it will still crash over time. Ron had stated in one of his article that to him, a sandbed with bacteria only is worthless to him, sand filled with critters is. Bacteria can multiply at a very fast rate given the right condition, but not the critters living in the DSB. Dumping in 4" or more sand & one will get bacteria breaking dwn NO3. The main interest of post is to discuss on how to maintain a DSB in the long run.

SO, having loads of critters will help one maintain a fully functional sandbed beyond 5 yrs with bacteria processing the excess nutrients & critters eating the detritus sink dwn & prevent clumping.

*note: All the tanks I setup is using DSB, therefore there is no reason why I doesn't advocate DSBs.

Happy reefing!

Wei

[yazid]

I have design DSB in my refugium such that the overflow water from the main tank goes to the refugium tank first before my sump tank area. This is to ensure that access food will find its way to the DSB in the refugium and settle there. This is to prevent "DSB starvation". I will also take the necessary steps to also "feed it" initially.

I've also reduce the sand from the main tank for aesthetic display only so as to increase the viewing area.

As for the sand, I'm using clean fine river sand w/o silicate. It is very very fine thus would be able to keep the DSB height at 4". On top, I did seed some of my #1, #3 sand. Also to allow critters of various size to choose the sand size they are comfortable with.

This is what I have just implemented from my readings on DSB and refugium. I will only know the results in time to come. Will report back if it works or when it breaks.

Hopefully we can learn from this implementation.

[Achilles Tang]

Ah Wei,

Ok so after all the hooha... you just meant to say that a sandbed is only as good as the amt of life it has???

Aiyoh... ok lah. All this talk abt recommending different depths is pointless. Less is not as good, deeper is better. Proven.

So the statement:

1) Inefficient breakdwn of NO3 due to hamper of diffusion within the sandbed. (claim by Bob Goemans)

... is untrue. That is how it is supposed to work. Deeper sandbeds cause anaerobic conditions for bacteria to process NO3. shallow sandbeds do not.

So moving on...

When sand clump together, its not like rocks with small holes & tunnel within. Its like a solid piece of plated rock. I have SEEN & help a friend of my to chisel & break the clump sand so that he can restart. If it clumps and function like a large LR, then I will also go for it. but its not going to happen. Might be due to the presure or compression, the clumped sand will compress into something like a plated rock with hardly any hole. Its simple, when u study geo where u learn about the layers below the earth. They are compressed.

Not true... I have never heard of DSB crashing after 2 or 3 years due to sand clumping. Even when parts of the sandbed has unfortunately clumped together, it is still porous. I heard of someone taking a piece of clumped sandbed and pouring water thru it... water still goes through at the same rate. It is like a piece of rough sponge.... just equally porous. Have you actually tried it?

So it is still in effect very much like LR but much more porous. And LR do get clumped up with detritus too, FYI. That is why people recommend blowing off detritus to clear the holes.

And please, I studied geography before, aced it too. Compressed rock is caused by geothermic pressure or simply crushing pressure from tectonic activity.

It would take lots of heat and tons of pressure to fuse sand into a solid mass of stone and that alone takes years or in the molten heart of a volcano. That simply cannot happen in a reef tank. clumping caused by bacteria activity doesn't produce granite or sandstone.

Moving on to life in sandbeds....

Pods are not the only creatures that live in sandbeds, all kinds of worms do too. And worms do not get eaten as quicky as pods.

So how now do you propose that we keep our sandbeds as populated as possible? Keep no fishes?

[Wei]

Hi AT,

Ah Wei,

Ok so after all the hooha... you just meant to say that a sandbed is only as good as the amt of life it has???

Not hooha lah. Just that u keep emphasizing bacteria only DSB. I want to hightlight the impt of critters living within also mah.

So the statement:

1) Inefficient breakdwn of NO3 due to hamper of diffusion within the sandbed. (claim by Bob Goemans)

... is untrue. That is how it is supposed to work. Deeper sandbeds cause anaerobic conditions for bacteria to process NO3. shallow sandbeds do not.

I will leave it to the rest. GUys can read the FAMA, feb issue, sand mail section yrself.

Not true... I have never heard of DSB crashing after 2 or 3 years due to sand clumping. As for clump sandbed still works?

Maybe should post a question to Ron regarding if a clump sandbed will still function that well since he got a part of forum specially for him. I personally seen 2 case of friend tank crash due to sand clump. which means, the DSB become a useless rock bed.

Still, i will leave it to the rest to decide.

And please, I studied biology, aced it too. Compressed rock is caused by geothermic pressure or simply crushing pressure from tectonic activity.

It would take lots of heat and tons of pressure to fuse sand into a solid mass of stone. That simply cannot happen in a reef tank.

I will leave it to the rest. I personally seen & handle it. min holes.

Pods are not the only creatures that live in sandbeds, all kinds of worms do too. And worms do not get eaten as quicky as pods.

of course i know. Theres lots more critters in DSB.

So how now do you propose that we keep our sandbeds as populated as possible? Keep no fishes?

Dun keep fishes???!!!!! I dun think yr tangs burrow into sand right. Dun get sand burrowing fishes or sand star that eats the live in the DSB. After cycle, allow a few more mths for the critters to multiply.

Going back to camp.

Wei

[Wei]

Hi yazid,

I agree with u. Its very ugly to see ones tank with 6-8" of sandbed not hidden away.

Logically, it should function as well as the main tank. If its a great success, we can say good bye to the ugly thick sandbed in the main display. Relatives who come will not ask, howcome yr sand put so much, ugly. WHy the sandbed inside got algae. U didn't clean yr sand? *FAINTED.

Do feedback on the results after errmmm, mths or more? Pple can learn from yr experience too.

Happy reefing!

Wei

[Achilles Tang]

Looks like we are still going around in circles, before we get lost, let's state the things we want to discuss abt:

1. Whether or not to have a sandbed ie. looks vs function.

2. How deep a sandbed should be for maximum nitrifying effects.

3. How to minimise sand clumping that could lead to less efficiency and potentially a tank crash.

4. How to encourage/replace more sand fauna /prevent loss of sand fauna.

5. Whether having a sandbed outside of the main tank can work as efficiently as opposed to having one in the main tank.

So my opinions again:

1. Whether or not to have a sandbed ie. looks vs function.

Having a properly setup DSB will help reduce NO2 and NO3 to very low/undetectable levels as opposed to no sandbed/shallow sandbed.

2. How deep a sandbed should be for maximum nitrifying effects.

Using #1 sand (local context), to MAXIMISE the efficiency of nitrifying bacteria that only grows in the anaerobic layer of the sandbed (deep deep down), it should be min. 6 inches which is already a compromise since the reef gurus are advocating that depth already using oolithic sand. Using any lesser depth would create more oxygen diffusion and therefore less nitrifying bacteria will be supported to process nitrates to harmless nitrogen gas.

3. How to minimise sand clumping that could lead to less efficiency and potentially a tank crash.

Wei's emphasis on sandbed creatures to stir up the upper layers is unargueable. It is important for these to be present to stir up the sandbed in their own little ways.

4. How to encourage/replace more sand fauna /prevent loss of sand fauna.

As stated, people build small pod 'piles' to encourage pod populations from declining. Actually, with the amount of LR present in reef tanks, it doesn't take much of the fauna to migrate to the sandbed to do their work. To introduce more sand fauna, we can only buy quality liverock and macroalgae clumps to replace declining populations as we don't get 'detrivore kits' here locally.

Feeding live phytoplankton will encourage the entire food chain to grow from bottom up. phytoplankton -> zooplankton -> pods -> fish.

To prevent total loss of sand fauna would mean no predators ie. fishes as the main culprit. It's unrealistic. Sea cukes do not consume pods or worms.

5. Whether having a sandbed outside of the main tank can work as efficiently as opposed to having one in the main tank.

Experiments are underway on whether a seperate sandbed placed in a sump or refugium will work better than having it in the main tank.

However, it is understood that you will need a larger or equal tank holding the DSB to the main tank's volume. Also unrealistic. Taking a cue from RC reefers, they have huge tubs of DSBs which they plumb to their main tank. With the 'under the stand' sump configurations that we normally have... we cannot provide the volume needed and therefore compromise on sandbed efficiency already.

Also you need to ensure that a high flow of water is needed to carry down detritus to the sump or refugium to work properly. Normally a refugium should not be having a high flow of water so as to create a peaceful refuge for microfauna to grow. So that means having a sump to hold the DSB. How big is the typical sump, especially after all the partitions are in and equipment like pumps and skimmers are placed inside?

Therefore, for a 'out of main tank' DSB to work, you need:

1. A large volume tank to hold the DSB.

2. You need ample water flow to bring detritus down to the DSB for it to effectively process it.

[pospeh]

Not to be completely out of topic, but DSBs are known to crash after 3+ years of use.

Ron Shimak, a proponent of the DSB system, whose own very system has crashed, has attributed it to accumulation of heavy metals.

Others who were skeptical of the DSB from the start, simply point out that a DSB is bound to crash. They analogize it as a septic tank that can only contain a limited amount of shit (heavy metals in Shimak's terminology), and once that amount is exceeded, the nasty stuff all leaks out and kills everything in the tank.

Plenums may solve this problem, but they are a pain to set up.

Thats why I perfer to stay with a proven system such as LR filtration.

[hongqixian]

Not to be completely out of topic, but DSBs are known to crash after 3+ years of use.

Ron Shimak, a proponent of the DSB system, whose own very system has crashed, has attributed it to accumulation of heavy metals.

Others who were skeptical of the DSB from the start, simply point out that a DSB is bound to crash. They analogize it as a septic tank that can only contain a limited amount of shit (heavy metals in Shimak's terminology), and once that amount is exceeded, the nasty stuff all leaks out and kills everything in the tank.

Plenums may solve this problem, but they are a pain to set up.

Thats why I perfer to stay with a proven system such as LR filtration.

I'm sticking with the shallow sandbed theory. To each his own.

[Tanzy]

You,

This thread is pointless! There are no absolutes in this postmodern shit hole of a world anymore. Nobody is willing to believe anything other than what they choose to believe even if the evidence is glaringly obvious. In the end, all this will be reduced to a battle of wits and not truth.

Bah! Humbug!

Do what you want and believe what you want. Join in the postmodern humanistic culture of our society. Be the best/worst you can be and live life to the fullest/emptiest. Someday, you'll prove yourself wrong.

Regards,

Me

[Achilles Tang]

Maybe the trend is shifting to expensive denitrators to keep nitrates at very low levels?

I may seem to be a DSB proponent but in my early days, I was advised that 1" of sandbed was enough... struggled with high nitrates produced by my bioballs.... later on, I increased my sandbed size to 4", and it became low quickly enough to convince me that DSB work. Believe me, I have used up a huge amount of AZNO3, carbon and salt in the beginning and if I have come across DSBs in the beginning, I may have saved myself some serious cash.

They are more pros than cons in DSBs! Why argue about a good thing? If it's time to change out the sandbed... change out the sandbed!

Talking abt cash and crash...

The question is: why do tank crash? Crash because of what? How do you define a crash?

So many factors come into play ie. size of tank, feeding habits, maintenance, stocking levels, additives used, water changes, circulation, filtration methods etc etc.

Pospeh.... tanks with shallow sandbeds, berlin method, dsbs have all been known to crash.

Ron Shimek is coming up with a theory for his tank crashing by pinpointing heavy metal accumulation but have yet to prove it extensively. Remember, it was just one tank. Some people have been keeping DSBs for more than 7 years without crashing.

Did you know that Ron suspected that it's heavy metals accumulated in sand AND live rock? He is telling us that we have to throw away our liverock and sand now after 3 years too!

So what then? Keep bare tanks, corals lying on the glass bottom?

AT

[Achilles Tang]

You,

This thread is pointless! There are no absolutes in this postmodern shit hole of a world anymore. Nobody is willing to believe anything other than what they choose to believe even if the evidence is glaringly obvious. In the end, all this will be reduced to a battle of wits and not truth.

Bah! Humbug!

Do what you want and believe what you want. Join in the postmodern humanistic culture of our society. Be the best/worst you can be and live life to the fullest/emptiest. Someday, you'll prove yourself wrong.

Regards,

Me

The wise resident turtle speaks!

Let's terminate the debate and worship his royal baldness!

You just joined the Hare Krishna sect didn't you?

[Ian]

After a few months can i increase the sand bed if i wanted to?

[Tanzy]

AT,

I don't think dressing myself in robes, have a funky haircut and chanting the name of a god will allow you to transcend the world to nirvana. Those Hare Krishna dudes are nice people, but definitely weird. Spoke to a few of them at a Hare Krishna Awareness society meeting before and my conclusion is that they don't think very much or some screw loose up there. I did donate £5 to their cause and got a book with a blue indian looking guy on the cover.

Ian,

Sure, but why? If you do it again, you'll get a diatom bloom and milky water for a while.

[onghm]

Ian,

Sure, but why? If you do it again, you'll get a diatom bloom and milky water for a while.

Hi Tanzy,

You mean adding sand will create diatom bloom even though bioload remain unchanged ?

Is it because new sand contain silicates ?

[Ian]

Ian,

Sure, but why? If you do it again, you'll get a diatom bloom and milky water for a while.

Just though that mine might be to low. About 2" only. If I used washed sand and use a pipe and a funnel to place the sand in slowly, would that help?

[Achilles Tang]

AT,

I don't think dressing myself in robes, have a funky haircut and chanting the name of a god will allow you to transcend the world to nirvana. Those Hare Krishna dudes are nice people, but definitely weird. Spoke to a few of them at a Hare Krishna Awareness society meeting before and my conclusion is that they don't think very much or some screw loose up there. I did donate £5 to their cause and got a book with a blue indian looking guy on the cover.

Ian,

Sure, but why? If you do it again, you'll get a diatom bloom and milky water for a while.

Heheh.... I was gonna say you started the Cult of the Turtle over there...

Anyway... I agree with the different theories on DSBs/plenums and their functions. I just want to clarify certain things before they get misunderstood. Especially if we (the more advanced hobbyists) don't speak up to clarify stuff.

Anyway, debate is interesting, and so is thebait you put at the end of a hook.

[Tanzy]

Just though that mine might be to low. About 2" only. If I used washed sand and use a pipe and a funnel to place the sand in slowly, would that help?

It will help but new sand always carry some soluble silicates on it. It will give a self limiting diatom bloom for a month or so.

AT,

That is so corny.

[lona]

oohhhmm...

*bell rings in the background*

OOHHHMM..

Don't know anything about the turtle cult, but me here's head of duck cult.

We dress up in feathers and worship the idol of the flat beak and wear the medallion of the webbed foot.

oohhhmm...

[pospeh]

Just though that mine might be to low. About 2" only. If I used washed sand and use a pipe and a funnel to place the sand in slowly, would that help?

Ian, one more caution.

If you add too much sand, you will kill off the aerobic bacteria living on the very bottom of ur current 2 inch sand bed, as the bottom sand layer become oxygen starved. It will create a mini cycle, and in the worst case scenario, it may crash your system.

[Achilles Tang]

Hmmm that's true... recommend putting in 1 inch every few days.

[pet]

Hi Guys,

1 thing missing from the discussion is the efficiency of DSB with and without a bottom supporting struture. I've seems various report and report using bottom supporting structure and seeding of egg shells helps.

Any commends,

Thanks Pet

[chanbi]

That is a plenum! will be another debate..

[Tanzy]

I use a plenum and although it takes more effort than DSB to do properly, it's only done once if you do it right, just like piping. No complains for the plenum systems. Working fine and doesn't release hydrogen sulphide even when the sand is stirred. Never heard of egg shells being used but I do know that the plenum is made of egg crate light diffusers on top of pvc pipe supports covered with netting.