Can someone tell me again why we don't like DSBs?

[jenglish]

Originally Posted by saf1

But see that is why it is also a "live" DSB. Litter boxes are not live and must manually be cleaned. DSB have living creatures under and on top of them. Mini stars, hermits, snails, worms, etc.

The argument isn't that detritus is there or can be there or not cleaned up, but proper animals and water movement pretty much take care of it. I mean - as you can see my sand is dirty around the class. Top part is clear on left side, right side has some top algae - but once my Queen Conch gets there, its clear...

Dunno - that is why I always stay out of these threads because they always get very religeous. Its not so black and white because people are using them with success.

So now the question is - how do you measure success. And wouldn't that be just as subjective?

Yes, critters eat the poop.... and then they poop. They can break it down to smaller pieces, some of which may be reused by the system. But we are feeding at least twice a week to twice a day. THis is a constant addition of nitrogen, phosphate, etc. Some of these atoms we can explain where they go (Nitrogen and Oxygen) but others like phosphates we cannot.

I could add Dung beetles to my cat box metaphor. If they could not fly out of the box, the fact they are using and breaking down some of the materials does not negate that the dung beetles poop. Constantly adding organic matter to the system is going to cause it to build up if we are not removing it in some way.

For me personally I like to keep a good amount of flow to keep particles in the column, a skimmer to take them out of the column and a ball of chaeto helping to remove N and P that are in the water column.


I think there is no argument that a DSB can be used successfully in the short term. Whethor a tank flourishes because of or in spite of the DSB can't really be said for certain... like most of the things we do in our tanks. But I think we can discuss the logic of the forces involved. To me the logic of magical animals that eat and don't poop is flawed and not a long term strategy.

[cloak]

Originally Posted by LobsterOfJustice

cloak - I think your picture perfectly illustrates why DSBs are a problem. I dont want any of that junk in my tank.

If you give a cat a litterbox with size of a spare bedroom, it will take it a long time to full up... but eventually it will...

To me, a deep sand bed just provides a large place to hold crap. Out of sight, out of mind, but it's still in your tank and can slowly seep out or cause problems later down the road.

Its just got too many rules. Dont add certain fish, dont have too many fish, dont feed too much, etc. Well I want a ton of fish and I want gobies and wrasses. I dont want filtration to limit what I can keep - I want filtration to allow me to keep MORE.

I think you might have misunderstood my post. Whether you try and clean your sandbed or not, which I never did, it's there, your not going to be able to get all of that out. The sandbed was pretty much put in for the sole purpose of denitrification, and that's exactly what it did until the end. My nitrates were low, if not zero, and the only algae I was battling was coraline. All the gunk your seeing was harmless. If it hadn't been for that crack, the tank would still be going strong today.

[peteyp923]

very interesting and informative tread. I am new to the reef community. I run a BB tank because a DSB seem very intimidating to me.

[saf1]

Originally Posted by jenglish

I think there is no argument that a DSB can be used successfully in the short term. Whethor a tank flourishes because of or in spite of the DSB can't really be said for certain... like most of the things we do in our tanks. But I think we can discuss the logic of the forces involved. To me the logic of magical animals that eat and don't poop is flawed and not a long term strategy.

Pet dung beetle - that would be pretty interesting

See here is the crux of the problem which you sort of hint at. And that is the argument of time. For example, you say they can be used successfully in short term.

Maybe the question should be a bit more broad and what is the average lifetime of a closed system salt water reef that we all strive to maintain?

Not pointing fingers but if someone is running a DSB and they have it up and running for say 7 years - is that considered short? I really have no idea which is why I'm asking. I don't know how long tanks stay up but I'm betting a lot of it has to do with too many factors to list such as luck, husbandry, etc.

Deep sand bend or bare bottom, star board, etc.

[LobsterOfJustice]

Originally Posted by cloak

I think you might have misunderstood my post. Whether you try and clean your sandbed or not, which I never did, it's there, your not going to be able to get all of that out. The sandbed was pretty much put in for the sole purpose of denitrification, and that's exactly what it did until the end. My nitrates were low, if not zero, and the only algae I was battling was coraline. All the gunk your seeing was harmless. If it hadn't been for that crack, the tank would still be going strong today.

It's not in my tank . And I doubt the gunk was harmless. It was just sequestered in your sandbed. Would you have felt comfortable pouring that water into your tank? I wouldnt...

And just because it worked for a while, doesnt mean it would be indefinite. To me, the illustration of all that crap means no, it cant keep going strong, because eventually theres too much crap...

Still waiting for someone to tell me: Where does the fish poop, uneaten food, detritus, "junk", go?

[mukymuk]

Originally Posted by LobsterOfJustice

Alright, one question. Where does all the junk go? What happens to it?

Nitrogen-based material ultimately ends up as N2 and bubbles out. This is the well known prime filtering feature of a DSB.

PO4? I really don't know, but I expect that it eventually precipitates or and/or gets put back into solution somehow. Hence, you still need a PO4 export.

I'm guessing you are refering to "DSB's build up crap" notion. I think the main point of argument there is that, given the right infauna, nothing of consequence builds up.

[saf1]

Originally Posted by LobsterOfJustice

Still waiting for someone to tell me: Where does the fish poop, uneaten food, detritus, "junk", go?

You have the same issues with any other closed system and tank bottom type. This is not a logical question to ask. That is why people run skimmers, sumps, or insert any number of other methods here.

This gets back to the masses setting up reefs differently. Yet in the end some form of robbing peter to pay paul is in check. Meaning we read, we see what is trending, we see what we like, dislike, want to try, etc. Not all reefs are the same yet the hobby is moving forward.

Cree LED's righ now are hot topics to debate. Is it fair to say they will be short lived because everyone is having success with MH's, vho's, t5's, etc?

As noted earlier there is a tank on this board keeping SPS and what not under T5's only. On another thread there is a tank owner that says its been up for 35 years.

I don't think its so easy to say it will not work when systems are. And my concern would be the so called "time" or "not yet" factor.

Where is the line drawn.

[Mike O'Brien]

Originally Posted by LobsterOfJustice
Alright, one question. Where does all the junk go? What happens to it?

My stuff goes down the drain. Sometimes you have to actually see the stuff, some see it when they finally remove a dirty sandbed. This is what goes into a sandbed every few days. I'd rather just remove it from the tank and not let it be broken into nutrients.

IMO the average sized tank just doesn't have the room for a DSB. You get some good years out of it, then it's problematic. In tank ends up with problems. In sump is even worse. Listen to these guys now and they tell you you need lots of flow so nothing can settle in the sand. Just makes sense not to have the sand there in the first place.

[mukymuk]

And just because it worked for a while, doesn't mean it would be indefinite

Is any method indefinitely effective? A DSB is no different than any other method in that regard--it's more a "good enough" type of thing. I think the main time limitation to a reef tank is it's owner's interest in keeping it running...

You're point is well taken though. A lot of "DSB's" do seem to collect crap over time. My suspicion is that such build up is more a result of compromises made in construction/maintenance of the DSB. What is above the DSB is probably just as important as what's in it.

A DSB in a display is essentially a species tank, IMO. That is, you become very restricted in what you can put in there that won't kill off/perturb the infauna.

My stuff goes down the drain.

Agree. Short-circuting the nutrient cycle is always best, from a strictly filtering perspective. I think some DSB'ers like the other things it brings to the party though--diversity of life being one.

IMO the average sized tank just doesn't have the room for a DSB

I agree. At least not tanks that are popular.

In sump is even worse

Why would it be worse?

[Mike O'Brien]

You have the same issues with any other closed system and tank bottom type. This is not a logical question to ask. That is why people run skimmers, sumps, or insert any number of other methods here.

IMO it's simply that skimmers take stuff out of the tank before it breaks down and sand beds do the opposite. They collect things and let it break down there where the nutrients get right back into the water.

It's much more complicated than the basic Nitrogen cycle thrown at the hobby. The sand is also producing Ammonia and Ammonium among lots of other things sand bed experts don't care to talk about.

[Mike O'Brien]

In sump is even worse

Why would it be worse?

Because it gets full much faster. IMO if you have sand in the sump it should be changed out every few years or so. I just don't see the average sump having enough movement going through it to keep detritus suspended and it just settles in the sand.

[Mike O'Brien]

Another point is that with BB, on average there is less equipment involved. Just the basics, skimmer, water movement and that's about it. No need to grow algae, no need to buy GFO and GAC, no need to use a bacterial system. In fact, the same low nutrient system can be run with none of these additives becoming popular lately. The only one you will probably need with it is AA's and maybe more fish and fish food to keep the corals fed.

[Mike O'Brien]

Is any method indefinitely effective? A DSB is no different than any other method in that regard--it's more a "good enough" type of thing. I think the main time limitation to a reef tank is it's owner's interest in keeping it running...

Exactly. There is no doubt that it's all up to the aquarist. All the different types of tanks we see here prove that.

All of the systems can work for a good long time, some just require more maintenance than others. I've been around long enough to see and try most of the ways there are to run a tank. IME BB is the cheapest and easiest system to run and it has the best chance of running long term without being touched.

[saf1]

Originally Posted by Mike O'Brien

IMO it's simply that skimmers take stuff out of the tank before it breaks down and sand beds do the opposite. They collect things and let it break down there where the nutrients get right back into the water.

It's much more complicated than the basic Nitrogen cycle thrown at the hobby. The sand is also producing Ammonia and Ammonium among lots of other things sand bed experts don't care to talk about.

Not to throw in another wrench - but what about those then that don't run skimmers or any other sort of water purifier.

It can get complicated.

[Mike O'Brien]

That's what DSB's were meant for. In the beginning they could do everything. Then you needed a skimmer, and it went on from there untill we were told it needed to be in a remote bucket that could be changed out easily without crashing the system.

[mukymuk]

Originally Posted by Mike O'Brien

Because it gets full much faster.

Why would a sump DSB get full faster than a tank DSB?

I agree that BB is a easier road to travel for many folks. But again, I think many DSB'ers like the biodivesity that it can bring--it's not just a filter.

Not to throw in another wrench - but what about those then that don't run skimmers or any other sort of water purifier.

You mean tanks that don't have adaquate export? Well, they will probably have all sorts of trouble with or without a DSB.

I think the original DSB design without a skimmer used algae as an export mechanism. A system like this isn't what most people want though--so we've collectively morphed the orginal concept into a lot of variations without changing the terminology. This is the real reason "we don't like DSB's", LOL.

[saf1]

I guess the problem is really me then from this threads perspective because I don't see it that way. "I" don't want to remove the sand nor was it ever my intent. And maybe that is why it is working for me.

I mean - at the beginning as you state it was sold to do everything. Yet everything else is added as you describe. Skimmers, lights, etc. Well, all those things are common in many of our systems here regardless of bottom type.

A complicated topic for sure....oh well.

[Mike O'Brien]

Why would a sump DSB get full faster than a tank DSB?

Because there is usually much less water moving through the sump, and even if there is a lot of it, it's usually very linear and more detritus settles in there. Refugiums are the same IMO.

I agree that BB is a easier road to travel for many folks. But again, I think many DSB'ers like the biodivesity that it can bring--it's not just a filter.

Sure, but that doesn't mean a BB tank has to not be diverse. Thing is that all you have to do is have some detritus around and the critters will come. It's like field of dreams. keep the tank a bit dirty and you'll have lots of worms and pods. Fish could be a different story. I've never bothered with sand fish though. My wrasse has been happy sleeping in his mucous under a rock for many years now.

I think the original DSB design without a skimmer used algae as an export mechanism.

IIRC that came after, but Shimeck does address that in his pamphlet. IMO that is one of the support mechanisms needed to run a DSB.

[Mike O'Brien]

Originally Posted by saf1

I guess the problem is really me then from this threads perspective because I don't see it that way. "I" don't want to remove the sand nor was it ever my intent. And maybe that is why it is working for me.

I mean - at the beginning as you state it was sold to do everything. Yet everything else is added as you describe. Skimmers, lights, etc. Well, all those things are common in many of our systems here regardless of bottom type.

A complicated topic for sure....oh well.

Yes they are now. We have advanced. Years ago nobody worried about Phosphate for instance. Nitrate was the problem. My point is that with a DSB, there are other things that are needed to make it function long term. Without it, those things are simply just not needed. Most people now just take a multipronged approach. Refugium along with skimmer for example. Look at the ecosystem, even they started with just algae, and later added the skimmer.

[jenglish]

And the Inland Aquatics beds are very deep, unsiphoned and most runnign undisturbed since about 1995 or so combined with Adey dump bucket style ATS. Those systems have their own drawbacks, but that is really a little off topic.

I think a BB does a better job of replicating the stony reeftop, that are often much farther from sand than our tanks allow. I think with everything you do it is important to look at the enviroment you are trying to recreate for your particular animals. For my current lagoonal system a DSB and the critters in it are part of the enjoyment for me. Is it more maintenance than a BB? Yes, but so is having anything in there.


I have sometimes wondered if since silicate based sands would not bind PO4 like carbonate how one would function long term

[Mike O'Brien]

I think it's been mentioned that the sand around a reef is nothing like a DSB. You can dig deep down and it's perfectly clean. No nasty cloud of crap coming from it.

[jenglish]

Originally Posted by Mike O'Brien

I think it's been mentioned that the sand around a reef is nothing like a DSB. You can dig deep down and it's perfectly clean. No nasty cloud of crap coming from it.

Thats what my DSB is like. But some will argue it is not a DSB in that it is only around 6 inches and I vacuum it regularly. I think some accumulation is also a matter of flow and the lack of places for detritus to go in our tanks.

[cloak]

[QUOTE=LobsterOfJustice;15999948]It's not in my tank . And I doubt the gunk was harmless. It was just sequestered in your sandbed. Would you have felt comfortable pouring that water into your tank? I wouldnt...

Pouring that water into a tank, what are you talking about? I'm not understanding that comment. Not sure if you have a sandbed, but I'd bet my life that if you took out all your rocks and used your hand to really stir up the sand, you'd see the same thing. I guarantee it. Like I said though, my nitrates were at zero, and coraline was the only algae I was dealing with. When you say that you doubt it was harmless, what should I have been seeing if it wasn't? That's pretty much what the tank looked like the day before it cracked.

[LobsterOfJustice]

Alright, this is moving too fast for me now.

But anyway, YES, it is different because there is no removal, just sequestering! Its like putting a filter cartridge in and never changing it! Filtersocks are changed and REMOVE material from the system. Skimmers, REMOVE skimmate, chaeto is harvested, REMOVING nutrients from the system.

Junk that builds up in a DSB is so much more than nitrogen. Where does all the rest (the MAJORITY) of the organic matter go?

[LobsterOfJustice]

Cloak, no, I actually just upgraded my tank on saturday from a 90 to a 180. The water that came out of the sandbed was clean enough to put in to the new tank. There was no crap. I scooped the sand out of the bottom of the 90 and put it in the 180. I have a diamond goby and 60x turnover which keeps my sand from getting rancid.

I just walked over the the 90 sitting on the floor. I scooped the sand out on sunday, it's still got like 1/2" of water in it. The water is clean and clear.