Sand Stirring substrates

[mojoreef]

Its really a complicated scenerio when you dive into it. DSB users use very fine sand in order to maximize bacterial populations (because it takes alot to do a little) but in doing so they loose natural diffusion, so they answered that with the use of critters to stir the bed, which you cant keep viable due to preditation, recruitment and natural selection. SO its kind of a paradox. Now when you take this and give it untrue limitations it can really screw folks up and has. Anthonys explanation of a dsb is probibly the best I have heard...well from a sand junkie anyway .
If truely folks could take any system and give thier true limitations folks would have such a better chance at making them work.
The same could apply for folks like myself that use BB systems. Its not like you take out the sand and life is all of a sudden perfect, you still need to work with in the limitations of the system.

Mike

 

[loohunter]

but i saw your tank years ago mike, and you had 2 huge remote sand beds, do you not have them any more? what about those sand burrowing snails , nothing eats those

 

[mojoreef]

Yep I gave those a shoot to, they turned into a kind of detritus settling tubs with sand on the bottom. After about a year I started to get measurable ammounts of phosphate from them so I took them out.


Mike

 

[spongebob lover]

But for more folks (typically) that stock their new DSB tanks in the first 4 months with fishes, overfeed in time, do not understand or push their skimmers, have inadequate water flow... and really are light on partial water exchanges, then DSBs are difficult to say the least.

ya you are totally right because i'm one of those , if i would have known better i would have never put sand on my tank, but i thought it looked so nice that i decided to give it a shot and little did i know, that i was gonna have so much trouble with it, right now its looking way better than what it was before, thanks to a powerhead and a skimmer.

sorry but are those sand burrowing snails bad? please tell me they are not because i have seen them in my tank :shock:

 

[NaH2O]

Mike/mojo and Anthony - I was by no means implying by reseeding with fauna you would ever get to natural populations.

Mike/mojo - you asked about sand stirrers. My impression of adding something like a sand sifting star is bad because once it depletes the bed of fauna, the star will die. If there are no critters, namely the "magic worm" that dives down further into the bed moving nutrients deeper (very little diffusion without it?), then doesn't the anaerobic zone get higher and higher? We had the conversation a while back on the importance of DSB critters (advanced topic forum), and I was under the impression that the worm was an important part of a functioning DSB. Without the worm breaking through the biofilms, the sandbed would be dominated by anaerobic strains of bacteria? For sure, I get the stirring of sand, and understand its importance, but I think the bacteria and fauna are important in a secondary role. I suppose it all boils down to what folks want their sand bed to do for their system. Sorry for getting this off in a tangent.

MikeS - I'm still waiting for my nuclear sandbed to arrive

 

[dnjan]

DSB users use very fine sand in order to maximize bacterial populations (because it takes alot to do a little) but in doing so they loose natural diffusion, so they answered that with the use of critters to stir the bed, which you cant keep viable due to preditation, recruitment and natural selection. Mike

I don't think you should overlook the effect of particle size on the depth to which detritus will settle into a sand bed. With fine sand, the detritus doesn't settle in to far by itself, and can be more easily consumed by critters that inhabit the upper layers of the sandbed. Let the sand get too coarse, however (and also uniform-sized), and the detritus will settle too deeply on its own. It is that deep-down detritus that can accelerate the problems with sandbeds.

 

[dnjan]

what about seagrasses?

Separate question - to what extent would/could true sea grasses (with roots) remove nutrients from a sandbed directly?

My "initially mixed reef" is gradually migrating towards a lagoon biotope, and I was wondering if seagrass in the tank would be able to remove accumulated nutrients in the sandbed before they re-enterred the water column.

 

[NaH2O]

I am a fan of DSBs, truly so. But mostly for aesthetics... and never for beginners.

Anthony - can you elaborate on the statement "not for beginners"? Why don't you think a sandbed is good for beginning aquarists? In my mind, the sand would take care of/store/sink initial mistakes (too high bioload, overfeeding, etc), as opposed to bb systems, where problems are real time, and can be somewhat frustrating from that standpoint. Algae growing in a BB system simply means something is currently going on, and not necessarily mistakes made awhile back. Just looking for some clarification.

 

[dnjan]

From my own perspective, a sandbed in a beginner's tank can hide the fact that they are overfeeding, have it overstocked, and/or don't have enough flow to keep detritus in suspension long enough. The detritus just disapears into the sandbed.

Perhaps the best approach would be sandbed for six months, then siphon it all out and go BB for 6 months, and then (hopefully after the three beginner problems identified above are taken care of) put in a new sandbed.

 

[Anthony Calfo]

cheers, Nikki

It's much as you state... and that IS largely the reason I am reticent to reccommend DSBs to beginner. The sinking of nutrients sneaks up on them from mismanagement of husbandry so common with newbies whereas the mistake (poor nutrient export) is obvious faster with bbs (and more easily corrected).

 

[MikeS]

MikeS - I'm still waiting for my nuclear sandbed to arrive

No worries Nikki...first thing I'll do after the tank transfer is box that bad boy up for ya, that way it arrives nice and fresh...

MikeS

 

[jnichols]

BUMP

Lets keep this thread going. It is very informative.

Jason

 

[spongebob lover]

welcome Jason !!!
i hope you enjoy reef frontiers, you'll see that there's a lot of fun in here and also tons of things to learn.

 

[wave98]

It seems to me that Anthony is "right on", with everything that he has to say here. It appears that a "remote bed", aka refugium, would allow us to "grow our own" micro-fauna, infauna, whatever, to feed our fish and the "sand stirring" critters, so that the sand stirrers don't have to die of starvation.

I think further more, that he is again, "right on", about the unreasonable cost associated with purchasing "kits", in the quantity that would be necessary if adding them directly into the "predator cage", and expecting them to sustain their own populations to the degree necessary to feed both the stirrers, and the Mandarins, or whatever other "water column predators".

Now comes the grain size and bed depth consideration, and how much depth contributes to recycled product returning to the water column, and how much( that depth which is remaining ) is just a larger "sink" that takes longer to fill, and start "fouling".

Do you have any thoughts on this Anthony, regarding say, "oolitic" on the DSB side of things, or even the 2-4mm version, that many "plenum" proponents like to advocate?

Thanks so much for your input, I just love this thread! . . . Wave98

 

[Anthony Calfo]

Good point Wave98,

IMO... I favor oolitic grains (under 1mm) because they are so fine/tight that they do not allow solids to penetrate deeply like coarse grains.

And so... more solid matter lingers at/on the surface and is exposed to water flow longer... hence a greater opportunity to be kept/swept into suspension and utilized by filter-feeders, fishes, exported by the skimmer, mechanical filters... whatever. This explains, to me at least, why my sand beds that have been broken down after 5 or more years (to me moved/bigger tanks, etc) have been staggeringly "clean" at all depth despite my lack of manual stirring. I simply have light bioloads, very aggressive skimming and very heavy water flow. And so... DSBs work easily for me.

Thus... I feel you can go deeper (bed depth) with finer grains, but not so with more coarse grains which allow solids to penetrate faster, sooner, deeper and subsequently require more sifting/stirring or even siphoning (ala old Undergravel filters!).

 

[wave98]

So Anthony,

We really are not penetrating all that deep into the oolitic substrate, because of the grain size, but it works pretty nicely if you keep an eye on "your" bioload, and it( the oolitic ) is keeping us away from "undue" detritus accumulation for the same reason.

I happen to believe ( in agreement ), that flow will take care of 98 % of detritus that would accumulate on the substrate from within the water column, if a little bit of effort is put into this condideration. ( including reasonably small "grains" at the surface )

Further, it seems to me, even with my limited experience, that the majority of "failures" in all systems, are the result of poor husbandry, and a lack of understanding by individual reefkeepers of the particular "system" that "they" happen to be "running", and their desperate search for a "cureall", which doesn't exist, and which they obviously have not found in their "last attempt".

I know, Anthony, that you have been preaching this all along, I just wanted to point out that I had come to this conclusion before having heard you say so.


It also would appear, that a good portion of the depths that are most commonly being used in "static" systems might be primarily a large "chemical sink" that extends substrate "life expectancy". ( looking for you input here )

Yeah, Anthony, I'm the plenum wasting guy ( currently ), and I would certainly appreciate it if you would take the time to post over there( Plenums, and the wasting option ), at least once anyway, just to keep us thinking.

Thanks Anthony, Wave98

 

[hopper]

Wanted to hop in on this as I have a 3" sand bed in my 110. When you say stir are you talkly about lightly over the top or a little deeper. Also how often can/should stirring be done? I guess this could be a case by case issue. Never seen a BB ocean floor before so DSB's have there place and I have always had sand. As far as sand stars, I had one for about a year and he did a great job. Then I noticed that a lot of my little critters were not as plentiful so I brought him back to the LFS in fear that he was depleting my sand of these beneficial organisms. Was this a wise decision to bring him back. I really liked the fellow. Thanks for starting this thread. Very informative.

 

[Maxx]

Anthony,
Great thread, and thank you for starting it up.

I've read your article in Advanced Aquarist Online magazine about sump return/closed loop manifolds. Is this the manifold you're refering to? It appeared that the majority of the flow from that design (in the article) would keep detritus moving towards the bottom of the tank.
Could you give us an example of your closed loop setup in your tanks. I'm one who is always seeking to increase and better the flow of my tank.

Thanks,
Nick

 

[Anthony Calfo]

cheers,

Hopper - by stirring, I usually mean just the top .5 - 1". The principal purpose being to keep solids in suspension and prevent them from accumulating excessively (and degrading0 in the substrate. You can imagine that bulk solids will not penetrate fine sand especially much deeper than the topmost layer. Hence the shallow stirring.

Maxx - I have a stickied thread over at RC in my forum there with a massive list of links to threads with posts and pics on manifolds. Dated with descriptions too. You can see a number of examples and explanations for how they work. But no... with adequate turbulent flow of any kind in aquaria, you do not need to worry about any such blasting of solids into the substrate (as per your question re: manifolds). Slow flow allows particulates to settle... but turbulent flow (hopefully) keeps it in suspension for more opportunities to export it via filter feeders/corals or simply skimmers/filters.

 

[aquariumdebacle]

I have been trying to keep these thoughts private as I would like to gain some empirical evidence to back up my claims. It seems to me as though the substrate should not matter in a properly designed system whether it is a bare-bottom or a deep sand bed system. If the substrate is not allowed to accumulate or "sink" organic material it should work just like a system with no substrate at all. What difference would it make if the substrate was solid? The accumulation is from nutrients creeping into (sinking) the substrate. If this not allowed with proper waterflow it seems to follow logically that the substrate is taken out of the equation entirely.

What I propose and will attempt to verify experimentally is putting the whole sandbed into the equation by having a very subtle flow of water on the magnitude of weeks turnover rate constantly pushing water up through the substrate creating an artificial convection current that will still be lacking oxygen. With an upward flow of water it would resist the gravitational tendency for sand beds to accumulate organic material.

The rest of the system will be the same with high water flow and vigorous protein skimming. I am not so sure of the phosphate removal in this proposal. It might have to follow the frequent water change maintenance schedule, in which case I'm sure Mikey would love to invite me over for a large dinner of small annoying black birds. It seems to me that, like my brain, a deep sand bed is only utilizing a small amount of its true carrying capacity. That and it is not saturated with enough alcohol! I plan to populate the system with schooling fish and then feed them with automatic feeders; to get an idea of the input involved and the resulting processing of the organics. I won't attempt invertrabrates unless I can get the parameters within reason (i.e. <1ppm phosphate, <2ppm nitrate, etc.)

a doo Ron Ron, a doo Ron Ron! Not ready to give up on the concept of DSB's!