DSBs & long term viability, the evidence against..

[weileong]

Back to the topic:

Everyone been very skeptical when i said about adding an air stone to DSB, everyone said i was wrong because denitrification only takes place where there is a lack of oxygen. Thats correct! Nothing wrong about it. But adding oxygen to the DSB, I am supporting the process of Nitrification. Pls bear in mind tat denitrification and nitrification are two different things.

Ammonia will be oxidised by the bacteria called Nitrosomonas spp. into nitrite and nitrite later oxidised into nitrate by a bacteria called NItrobacter spp. This process is an oxidation process. It therefore requires oxygen.

This is nitrification process.

And whereas for denitrification, i believe everyone knows about it.

So by adding oxygen to the DSB, it has been proven that it is possible for these two processes can be taken place in close proximity. "Anoxic microsites within fecal pellets and detrius will provide a habitat for anaerobic bacteria, while surrounded by porous aerobic waters" as quoted from Julian Sprung's book

And by adding oxygen to your tank via an air stone, you oxidise ammonia into nitrate faster by rapidly causing the aerobic bacteria to work more since they have more oxygen now. And you have higher nitrate but lesser ammonia. And given for times like now, isnt it becomes easier that we can remove nitrate faster by the effective breakdown of nitrate to nitrogen gas by the bacteria in DSB and also through our effective skimming (i assume everyone has a good skimmer)?

So i seriously dont find anything wrong to add oxygen to my DSB. Afterall, its no different from adding ozone. Ozone is just O3 which is an unstable structure compared to oxygen, but ozone when exposed to other elements in water will still break down to give oxygen. Given for this, why not save some money and use a cheaper source of oxygen?

Just my 2 cents worth..

Sorry just some question regarding your post.

First you said adding an air stone to your DSB

Everyone been very skeptical when i said about adding an air stone to DSB

then you said adding oxygen to your tank via air stone.

And by adding oxygen to your tank via an air stone

So which one do you meant? If the former then I guess this is simply lack of common sense, you are going to stirr up the sandbed causing the tank water to turn cloudy and that will stress your LS.

If you meant bubbling air via an air stone then will add lots of micro bubbles to your tank. This is not necessary as a skimmer would have already provide for the necessary gas exchange.

Ozone is just O3 which is an unstable structure compared to oxygen, but ozone when exposed to other elements in water will still break down to give oxygen

Ozone oxidize organics directly whereas saturation with oxygen is more of a passive method. They are different. When ozone "breaks-down" (like what you called it) into oxygen, it has already oxidize and removed the organics and at the same time raise the ORP in your tank.

[Terryz_]

With regards to Terryz_:

Not a debate. Formation of hydrogen sulfide i believe is an imminent process (correct me if i am wrong). I do not believe you can run away from it Even if in DSB, you will get hydrogen sulfide and not to mention inside plenum. Hydrogen sulfide formed in plenum is because of the lack of oxygen saturation inside the system and i believe if i am supposed to starve my DSB of oxygen, it will also produce hydrogen sulfide. The reason why we didnt get it is because of the constant exchange of gases through our skimmers, the waves caused by our currents, our occasional water top ups etc. So our oxygen level in our tanks can never really drop down to <0.5mg/L without any unforeseen circumstances but given for blueheaven, i do not know how he managed to do it.. but i believe tat gas sure stinks! If you ever watched documentaries, when they filmed life deep under the ocean in those trenches, you will see gases coming out of some chimneys, those are hydrogen sulfide. and ya, its very black!

I believe hydrogen sulfide is the black patches in the DSB...

Actually hydrogen sulfide will not form in the DSB if the DSB does not exceed 4 inch... From what i experience...

The reason why a plenum system will prevent the formation of hydrogen sulfide is becos the gravel is being sandwiched between the highly oxygenated aquarium water circulating above it and below it the plenum water, which maintains a low but generally stable level of dissolved oxygen... So being sandwiched between these oxygenated zones tends to prevent the formation of hydrogen sulfide...

My 2cent...

[Ancelot]

Wahahaha!! Of course not ask you to put an air stone into the DSB la! *pengz*

Just on the surface.. dont need to touch the DSB. Just inside the tank all can! except for touching the DSB.

I think wat you said abt the air stone is not really accurate. I agree tat there will be micro bubbles IF you use an air stone with tiny pores but if you use those luohan with bigger pores, i think you get lesser micro bubbles. But adding to this, bigger bubbles are actually not a bad thing because they create waves the moment they break up on the water surface. Point to note dude.. no offences.

Just my 2 cents worth..

I think really gotta ask ozone abt itself. But what i learnt in chemistry is that ozone is a very unstable covalent oxygen compound. Therefore, i believe when ozone goes into water, you get O atoms and O2 molecules as it breaks up. (Actually there are some chemistry theories which are also hard to explain so i keep the points short) Thats where ammonia gets its oxygen to oxidise into nitrite and then nitrate. Thats why adding ozone, you have undetectable nitrite because ammonia is mostly oxidised to give you nitrate.

And i think i was talking abt the source of oxygen for ammonia in the nitrification process. not about the oxidation of organics. but anyway thanks for sharing tat with me. I never studied abt ozone in details before..

Just my 2 cents worth..

[Ancelot]

The reason why a plenum system will prevent the formation of hydrogen sulfide is becos the gravel is being sandwiched between the highly oxygenated aquarium water circulating above it and below it the plenum water, which maintains a low but generally stable level of dissolved oxygen... So being sandwiched between these oxygenated zones tends to prevent the formation of hydrogen sulfide...

My 2cent...

Oh okie.. thanks dude.. i think i will experiment it soon.. thanks a bunch for the info!

[Ancelot]

I believe hydrogen sulfide is the black patches in the DSB...

Actually hydrogen sulfide will not form in the DSB if the DSB does not exceed 4 inch... From what i experience...

DSB will be effective if you go high if not go wide..

Just my 2 cents worth..

[Marineman]

By what statistics do you say this?

You can read more about it here

http://www.reefcentral.com/forums/showthre...7&highlight=DSB

[weileong]

With an overflow box and wave make the water surface already "broken" and the organics floating on the surface will be removed by the overflow and get skimmed out.

Like I said before adding airstone has more disadvantages than advantages as the air exchange is already provided by the skimmer. Unless you are talking abt having a 4x4x2 reef but with a skimmer that is smaller than a weipro 2013 in terms of size

Worst of all you get bubbles flying around in your tank. Oh unless you tank has little to no water movement and lack of skimming so I can see what you need to add air bubbles to your tank. You use those "louhan" type air stones the bubbles are also big and that has much lesser surface area for oxygen exchange, I really do not see much advantage in doing that unless you had made some comparison before like using a TOC meter to measure the amount of organics in your tank Or using a DO meter to actually measure the oxygen levels in your tank or using an ORP meter to measure the state of health of your tank.

Other wise your bubbling of big bubbles in the tank does not make much sense to me.

[Marineman]

Just my 2 cents worth..

Wa lau Ancelot, you have given a dollar's worth already!

Just kidding, subject is too technical for me................

[Ancelot]

Well, I am just applying what i learnt from books and back to here. Anyway the idea of adding oxygen is for those having a DSB inside the refugiem to enhance the efficiency of the nitrification process in the sump. It's just a suggestion. Anyone can try.. Resulting results how i am very interested to know...

Marineman:

Wahahaha... enough coins to spare around la.. but tats erps.. off topic?? Sorry AT!

Just my 2 cents worth...

[weileong]

This is a technical forum at least where the SPS and advanced reefkeepers forum in SRC is concerned, please post only relevant facts with hard data to support your points and not just "suggestions".

If suggestions then you must state it clearly in the first place so reefers will not be misleaded

However like I mentioned in my previous post, there should be no different at all.

Sorry for the moderators but can't help it

[Achilles Tang]

Ancelot,

Everyone been very skeptical when i said about adding an air stone to DSB, everyone said i was wrong because denitrification only takes place where there is a lack of oxygen. Thats correct! Nothing wrong about it.

But adding oxygen to the DSB, I am supporting the process of Nitrification. Pls bear in mind tat denitrification and nitrification are two different things.

One doesn’t have to purposely introduce oxygen into the DSB for nitrification to work! If there isn’t enough oxygen in the tank for aquatic life in the first place, providing enough oxygen for bacteria is a moot point!

Ammonia will be oxidised by the bacteria called Nitrosomonas spp. into nitrite and nitrite later oxidised into nitrate by a bacteria called NItrobacter spp. This process is an oxidation process. It therefore requires oxygen.

This is nitrification process.

And whereas for denitrification, i believe everyone knows about it.

So by adding oxygen to the DSB, it has been proven that it is possible for these two processes can be taken place in close proximity. "Anoxic microsites within fecal pellets and detrius will provide a habitat for anaerobic bacteria, while surrounded by porous aerobic waters" as quoted from Julian Sprung's book

And by adding oxygen to your tank via an air stone, you oxidise ammonia into nitrate faster by rapidly causing the aerobic bacteria to work more since they have more oxygen now. And you have higher nitrate but lesser ammonia. And given for times like now, isnt it becomes easier that we can remove nitrate faster by the effective breakdown of nitrate to nitrogen gas by the bacteria in DSB and also through our effective skimming (i assume everyone has a good skimmer)?

No one adds airstones to their reef tanks unless it’s a fish-only tank or a tank with very poor oxygen levels eg. Poor water circulation. A good example would be a quarantine tank or LFS holding tanks that are not skimmed. As long as there is exposure to air and there is sufficient motion for air-water interaction, there is no need for supplementary air stones. Ever heard of wet-dry filters? Most newbies have bioballs in their sump or overflow and enough oxygen is present for the aerobic bacteria to quickly process ammonia & nitrites into nitrates.

One also doesn’t have to cater for additional airstones as the typical tank would have enough dissolved oxygen through the bubbles introduced into the skimmer column or water going through the overflow into the sump.

So i seriously dont find anything wrong to add oxygen to my DSB. Afterall, its no different from adding ozone. Ozone is just O3 which is an unstable structure compared to oxygen, but ozone when exposed to other elements in water will still break down to give oxygen. Given for this, why not save some money and use a cheaper source of oxygen?

You do NOT have to add oxygen to the DSB! The top levels will have enough oxygen to support nitrification and the bottom layers certainly should not be exposed to oxygen at all.

Ozone is something not to be trifled with and should be only applied with caution and in minute amounts but with the aim of burning off organics & killing bacteria and not as a means of oxygenating the water, much less the sandbed!

AT

[optimus prime]

so Berlin method still works the best?

[RAV-65]

I get this impression that Berlin methof not sufficient to remove nitrates completely... is it true??

If this is considered , kindly ignore...

[aquabeAnz]

i hope this can help as a better reference for newbies and pros alike...

Let's start a poll to observe some of the main criteria for a great DSB including the following:

1. thickness

2. maturity ( how long kept? )

3. percentage uncovered by LRs ( as a % of whole tank's surface area )

4. good circulation above DSB

5. OTHER GOOD CRITERIA like plenum ( optional to add )

can we do that boss ???

[[JS]]

is my dsb not very stable ?

[[JS]]

close up

[tayhonglee]

hi all,

i know its a little out of topic here, but why not consider starboard tanks? i read this bomber guy's thread in rc, and a loooong read it is, and what he says makes sense (at least to me). lots of currents to skim the crap outta there before it can form nitrates. and this other guy, idrhawke (wrong spelling?), drains the bottom of his dsb quite often. lots of stinky stuff according to him, definite no no for tanks.

so what do you think? i know they're fugly, but the ones shown aren't half bad. my next tank gonna be a starboard.

henry

[ddr]

A recent study of my DSB has also yielded evidence that it has become rather devoid of microlife, a crucial factor in the effectiveness of a DSB.

AT IMO this is the major downfall with a DSB, the need to reseed. I see reseeding as renewing or cleaning of the filter.

Could you imagine how dirty a Carbon filter or skimmer would be if it wasnt changed or cleaned in 5 years? I couldnt see either working at all after 5 months even.

We put a lot of effort into cleaning every other part of a tank, why should a DSB any different? It is a living filter that still needs maintenance.

Dan.

[Bandit]

Couldn't agree more Dan... small price to pay for such awesome filtration

[Sabella]

Taking a more simple view I have one question -

Given SPS need for very good water flow how is the required water flow achieved without creating a sand storm?

How is long term water quality maintained with the build up behind your LR which becomes very difficult to syphoned away?

A BB tank allows for the use of a powerhead and hose and blow out anything from behind the rocks where as this becomes very difficult with the DSB. Flow ultimatley is reduced.

IMO BB looks unnatural and ugly but it seems a simpler long term approach.

Sabella

[bluesky]

I understand that One principal benefit of DSB is the Nitrate Reduction. Right? Now if we use BBT, then how we propose to reduce NO3? Aggressive skimming will remove 100% of NO3? Is this feasible? May be reduce feeding too...?

BBT with strong water current, "any how shoot", is very tempting, especially SPS dominated tank. But, I am concerned of the NO3 reduction too. Any advice here? TQ in advance.

[tuan]

Followed this thread for a while and thought I try out my comments here as there seem to be less flame throwers about!

With all this 'fashionable buzz words' around, DSB/BB/Starboard blah blah.. it's easy to forget the basic principle of a reef tank filtered by live rock.

The so called fashionable 'BB' is nothing new. The principle of a tank with living rock and skimming was started many years ago called the "Berlin method". The point is porous living rock has the capacity to fulfill the complete biological filtration cycle including denitrification.

Many of us had successful tanks then for many years with just live rock filtration, good circulation and skimming.

DSB was an 'invention' later which basically 'discovered' the fact that a few inches of sand can *also* provide denitrification, effectly reduce the amount of live rock you needed to have with the advantages of:- reduce cost, better for environment and more space in the tank.

Aggressive skimming is not exclusive to any method. It's principle is simply remove as much waste (both particulate and dissolved organics) as possible before the waste has a chance to be broken down into the water column (and therefore the biological filter has less work to do).

Another myth about flow and DSB... it is possible to have high flow rates and sand. In the reef the flow rate is many times what we can ever dream of achieving in our glass boxes, but is the water column completely solid with all the sand that's around, nope. It's all about placements of the pumps and chosing the types of pumps. If you have narrow jets blasting down or hitting the glass so hard that they deflect down into the sand then yes you will get sand blowing around.

In my tank I have 60x tank volume flow rate, and a large DSB, admittedly the large area and depth make it easier but there is still a lot of flow and the sand doesnt move about that much. There are sand dunes etc.. and some does move at the start or if I change the flow somehow, but after a while it all settles down.

So why is there so many tank failures from DSBs? The answer lies with the reef keeper!

Many people simply read about DSB on the web and without understanding the principle of it and thought:- wow, this is easy right, you just throw in a few inches of sand and that's it! Skimming is neglected. Waste exports (PO4) weak.. predators added (sand shifting star fish/ blue cheek gobies) all aim towards 'keeping my sand pristine'. Well... it's no surprise then that the tank crashed.

Oh yeah.. the sand is leaching PO4 this and that comment. Well.. sure, if the sand (and the rest of the tank) has been immersed in sky-high PO4 all this time then yeah, it'll leach some back. Now had the PO4 been non-existance all this time then how can it be leached back from the sand? It can't.

Another popular one is the black sand of death. Well.. if you go and disturb the sand bed and turn it upside down then sure enough you'll have problems. Say what would happen if you go and split all your live rocks into pieces within the tank? Yes yes.. the inside of your beautiful living rock is also black and stink of rotten eggs too, it's meant to be, in the anoxic environment that's what you get.

So there... that's my two cents worth anyway

[madmac]

there are failures with DSBs that comes from ppl who are very passionate abt their hobby... and thats the real sad part about it. This 'filtration'/'equipment' DSB methodology hasn't been around long enough for results to show... for those who have tried it a few years, the results are just starting to tell.

DSB are good, so long as its ability to sink the NO3 continues.... it gives you the impression that NO3 is 'zero' because it can absorb it. It doesn't do denitrification... because if it does than the in-shore waters would hv zero nitrates too. It is a model of what happens in nature when there is lots of sand... no different...

[tuan]

It doesn't do denitrification

But it does. That's the point of the deep sand.. the deep layer of sand has anaerobic bacteria which consumes nitrates and produce Nitrogen as bubbles. Exactly like the pores in live rocks. In fact.. just like the bottom of a plenum system.

The long term problem is when the sand has become a solid clump which inhibits the diffusion of water down to the lower layer and so the anaerobic bacteria have no food and die off.

You have exactly the same problem with live rocks in a poor environments. After a while the detritus build up, the algae growth etc.. block up the pores in the rocks and you will also get zilch for denitrification. The analogy is to wrap your live rocks in food wrap/cling film.

[scarab]

I've heard somewhwere about this term of 'recharging' DSB, sort of like renewing or cleaning the DSB. Any idea how it is done, coz stirring the DSB has detrimental effect to your tank?

And the critters to keep the DSB alive, what types to intro?