DSB obsolete, Barebottom trend?

[Clownfish]

1 or 2 years back everybody was advocating n strongly recommending DSB... but now, the trend seems to be going towards anti-DSB... some pple even went ahead with barebottom tanks... wonder y this is so?

AT went barebottom n danano has removed his DSB... hmm... can anyone point to me wat caused this change of trend? seems like i hav been missing stg lately... thanx!

[ciaolong]

who knows

i just installing a dsb i find it really useful since my system is huge >.<

[Clownfish]

hmm... seems like it causes some phosphate leechin prob in the long term... but realli need to do until extreme == barebottom meh?

[ciaolong]

i have to say bb is not for the faint hearts

its really hardcore ><

to make it look nice must clean the bottom every day siphon

must be planned right or u get collection below rocks (pain in the ######)

i am using dsb cause the coral system need to get rid of the nurients plus i like the natural way better =) i guess the only problem after 2 - 3 years u gotta replace the dsb .. =( maybe thats why it leaks phos ? i should read up on it more

[RAV-65]

I for one might be going for DSB again when I set up my new tank again, coz used to have DSB, den change to Plenum, now going back to DSB again, but would like to have it in the sump with a separate chamber from the main sump, i.e. having 2 sumps, so dat when I wan, I can detach the DSB sump and change out all the sand...

Still researching on the viability of this...

[iantoh]

hi everyone,

tis a down time for a DSB believer i think. everyone's seemingly so convinced of the ill-effects of the DSB system that its honestly quite unbelievable. the DSB has been in use in public aquaria and is championed by most noted marine aquarists, and has been tried and tested past a decade now (two ten year plus examples, the waikiki and monteray bay aquariums, and eric bournman's personal tank featured on reef.orgs a while back)

i have tried to write up replies to these posts because my DSB has served me well all this time, and i figure it deserves some defense, seeing as it is unable to speak for itself, so i shall try to recap the major arguments on both sides for you, albeit entwined with my DSB philosophy.

the barebottom perspective:

1) the bare-bottom system is basically the extreme manifestation of the use of powerful skimming as advocated by the Berlin system. as skimming is about the removal of organics within the water column before it can be broken down into nitrites, nitrates, phosphates, etc, the best way to efficiently remove as much of this organic material as is possible is to have excellent water circulation to keep water-borne all the wastes that are produced within the tank. a DSB or a shallow sand bed for that matter, will logically be counterproductive towards this end as there will invariably be dead spots if you dont wish to blow sand everywhere, hence, the bare-bottom idea.

it makes sense really. theres no actual need for cycling of a barebottom tank seeing as the entire premise is to prevent any nutrient cycling from taking place within the tank, and to remove all nutrients before it breaks down. the thing is, it is not possible to entirely skim every molecule of water at every instant, so it is inevitable that nutrients will still break down within the barebottom system, either within the liverocks, or in the water column, leading to a build up of nitrates and phosphates eventually.

the DSB system:

1)heres where the DSB comes in. a functional DSB requires at least three to four inches of fine oolithic sand, the rationale being to create varying levels of oxygen within the sand bed. the top two inches where oxygen is lowered but still present will allow bacteria that convert ammonia to nitrites and nitrites to nitrates to develop and colonize. the bottom last inch is ideally undisturbed, even by sandsifting stars or gobies (perhaps only explored by worms as three inches is deeper than most critters care to venture). this last inch should be kept anoxic, that is, as an oxygen-less area to allow the bacterias that break down nitrates back into nitrogen and oxygen to survive and grow. the problem with this is that in an oxygenless environment, hydrogen sulfides will accumulate. this however, is not meant to be an issue if the sand bed is left as it is, to function as a sand bed for nutrient cycling. DSBs have been in use properly for over a decade without any sulfide leeching in numerous public aquariums, etc. the key is in utilising a correct depth of sand. very often, people use less than 3 inches of sand. with a half-baked DSB of say one to two inches, the bottom last cm or so is likely to become anoxic with time through the compacting of the sand, and will allow the colonization of anoxic bacterias to go to work there, but with this anoxic region will come hydrogen sulfide accumulation, and the risk of resultant leeching because a shallow sand bed is easily disturbed, both by the aquarist as well as by the life within the tank. this is usually the case of how sulfides are leeched into the system. its the same with liverocks. as bro tuan mentioned on another thread, the centre of liverocks, if you break one up, are black and full of hydrogen sulfide. this is because this is the anoxic region deep within the rock where bacterias break down nitrates (this is the very reason why we have so much liverocks in our tanks, for nutrient cycling). now, the same way that your rocks dont cry out to be broken within your tank to release these chemicals, your DSB similarly does not ask of you to disturb it.

as for the issue of PO4, i think this issue has to do with overstocking more than DSB, or any sand bed. the link is most likely spurious and incidental. alot of reefers keep alot of fishes these days due to the ability to export organics provided by powerful skimming. but wastes will break down within the tank to some extent no matter how powerful the skimming and how great the circulation, and will eventually cause nitrates and PO4 to build up. this is especially so if there are no macroalgaes within the tank or sump to absorb these nutrients. PO4 mainly enters the system through the foods we feed our fishes, in particular, foods for herbivorous fish such as tangs. the reason why we are often advised not to keep more than one or two tangs per closed system is not just because of conspecific agression, but also because of waste build up issues. phosphate is a primary constituent of all plant matter, and herbivorous fish such as tangs will require foods such as nori, macroalgaes or formula 2. all of which are high in phosphate content. the excretions from these fish will then cause the build up of PO4 within a system, and not the DSB. both ways, as i believe time will tell, the barebottom system will also experience PO4 issues as long as the tanks are overstocked.

there is also the misconception that PO4 is the chief factor in diatom or other microalgae growth within our tanks hence the desire to eradicate PO4. for sure, phosphates are required by plants for growth, but to deal with diatoms and cyanobacteria, silicates are more crucial. it has been proven that when silicates rise above 0.05ppm, diatoms will grow prolifically, and diatom gowth is highly correlated with silicate levels. hence, an easier method to prevent diatoms would be to remove silicates. heres two great articles on this matter:

http://www.reefs.org/library/aquarium_net/0297/0297_3.html

http://www.advancedaquarist.com/issues/jan2003/feature.htm

either ways, i think silicates and phosphates are necesary for the photosynthesis of zooxallanthae within corals so entirely removing both will not be a desired thing. and reverse osmosis or distillation processes that we use for our top up water may remove hard metals and chlorine and all that, but it has similarly been shown that the ability of the resins to remove silicates is short lived. i think the best way for us to better improve our tank water quality is to use phosban that is a resin for both phosphate as well as silicate removal. sadly though, i havent seen it on the local market.

well, hope that fills you in sufficiently on the current trend of barebottom systems. i think the barebottom system has its merits, as it basically extends out of the Berlin system, but that overstocking will still invariably cause nutrient and chemical buildups even within the best maintained barebottoms. same with DSBs. just that proper DSB systems have the added benefit of complete nitrogen cycling to help with the nutrient breakdown.

cheers everyone,

ian

ps: sorry to ramble on so long. i'm quite long winded i think

[nicky30092002]

u r surely long winded ,, but u gave a detail explaination!! well said!

[planetg]

this is certainly a never ending debate. make a sure on RC and ORA and you'll find tons of fire!

however, some people do have huge success with DSB. look at some of the tanks in SRC. they are pretty amazing. but can u guanrantee it will last for years. Is it a time bomb? many do realise that and turning to BB for that security.

ultimately, it's your husbandry and techniques. can u ensure enuff flow to every single inch of sand? are u on enuff to do 75% water change weekly?

to most the answer is no and thus we turn to BB cos we see shit easily and we know by the look of the base we gotta do some cleaning!!! haha

perhaps my explanations are not scientific enuff to explain why but as long as my livestock are growing well with colours, both will work!

cheers

[Kelmen]

BB is probably the simplest approach compare to the complexity of the DSB.

- One only need to work hard adopting BB (labor only)

- One need to know and apply the proper setup of the DSB (knowledge, experience)

Nowaday, I just don't feel right looking into BB tank. Something missing, just don't look right (personal preference)

With days passed and constant digging in RC, more is being learn about the DSB.

Recently, the prof stated the surface volume of the DSB play a factor as well.

However, at another subforum, some stated positive result with fast flowing running over a DSB with just a bucket only.

I even come across a thread long time ago, someone is taking a step ahead, by combining the DSB and the plenum, think its called CWP.

Running with DSB, and a feature to drain the bottomest water, and hence lesser need for water change, as he claimed.

So, if one just to adopt or follow -> BB

If you like challenge, and prefer natural approach -> DSB

If you are more than that, try pioneer something, like combination, or refinement.

[Kenji80]

I was at Aquarama 2005 and someone posted a question to Anthony Calfo regarding BB and DSB.

He mentioned that DSB is more suitable for LPS and Softies and BB is more suitable for SPS. I believed this is why some of the SPS keepers had changed from DSB to BB but he did not mention anything bad about DSB.

[FuEl]

I always believe a DSB or a sandbed of some sort has its benefits. It will give you a natural zooplankton source if you have enough critters (like burrowing polychaetes,etc) to maintain the DSB. The danger of a DSB is when these critters are not kept in check and they decline to dangerously low levels. When insufficient movement occurs in the sandbed, that is when compacting of sand and building up of hydrogen sulphide occurs. My next tank will probably still have a sand bed, however if not for the purpose of denitrification, a shallow sand bed will still provide additional surface area for colonisation of bacteria and proliferation of micro-organisms which can't be a bad thing when you consider the potential micro-fauna that a sandbed can support. Leacing of hydrogen sulphide has been the concern of many. However, it is only dangerous if it leaches rapidly, which can depress the pH of you tank. Natural leaching occurs slowly, and a stable system should be able to withstand such leaching.

In addition, it also depends on the livestock you intend to stock your tank with. If you go BB, you definitely can't have fish like jawfishes and other substrate dwelling fish. They can still survive, but it would be plain torture to them in my opinion.

I've had flame scallops survive to close to a year in my tank with a "plenum" below a shallow sand bed. I don't attribute this to feeding as I believe some form of zooplankton were proliferating below this "plenum". It further convinced me when a Stongobiops nematodes goby went missing under this "plenum" for weeks. I thought it was dead since I did'nt see it feeding for many weeks. I was pleasantly surprised when it appeared one day with a bulging belly and almost 1.5X the original size it was. I believe this shows the potential benefits of providing a sand bed in which organisms can proliferate and provide a constant and possibly endless food supply if maintained correctly. Corals will benefit too, since they need protein sources other than light. Even SPS requires feeding for optimum growth. I always believe a thriving bioscenosis is better than regular addition of dead/concentrated protein sources.

[ciaolong]

BB is probably the simplest approach compare to the complexity of the DSB.

- One only need to work hard adopting BB (labor only)

- One need to know and apply the proper setup of the DSB (knowledge, experience)

Nowaday, I just don't feel right looking into BB tank. Something missing, just don't look right (personal preference) 

With days passed and constant digging in RC, more is being learn about the DSB.

Recently, the prof stated the surface volume of the DSB play a factor as well.

However, at another subforum, some stated positive result with fast flowing running over a DSB with just a bucket only.

I even come across a thread long time ago, someone is taking a step ahead, by combining the DSB and the plenum, think its called CWP.

Running with DSB, and a feature to drain the bottomest water, and hence lesser need for water change, as he claimed.

So, if one just to adopt or follow -> BB

If you like challenge, and prefer natural approach -> DSB

If you are more than that, try pioneer something, like combination, or refinement.

i have to say that dsb are not complex people just make them complex ....

dsb can be the most easiest bio filteration u can do which is just really easy to keep (for all the lazy ppl)

as a said be4 bb is just for the really hardcore people who love cleaning their tanks every day

i find alot of sps tanks in perth are going starboard but bb

but i guess it almost the same

[daimy068]

I think that whatever system you choose, still have to be conscientious in your daily/weekly chores (water change, removing waste from sandbed/bare-bottom, replacing burnt out bulbs/tubes, doing tests for NH4, NO2, NO3 etc). Also, make sure equipment is cleaned and serviceable. Generally, good housekeeping.

Just my $0.02!

[Kurt Cobain]

I think that whatever system you choose, still have to be conscientious in your daily/weekly chores (water change, removing waste from sandbed/bare-bottom, replacing burnt out bulbs/tubes, doing tests for NH4, NO2, NO3 etc). Also, make sure equipment is cleaned and serviceable. Generally, good housekeeping.

Just my $0.02!