The Great Substrate Debate We All Like To Hate

[Dave ESPI]

I was skeptical about the overwelming popularity of DSB's and since having been working on a "nano-reefing" book for the past 11 months, I wanted to debate with those with knowledge and more than a one line reply as to you for what YOU perferr when it comes to DSB and Plennumn design and why you chose one over the other. OBVIOUSLY we are running nanos, but I do have a plennumn in 2 x 10 gal tanks, so for the sake of discussion...

PLEASE LIMIT YOUR INPUT TO TANKS BIGGER THAN 10 GALLONS... UNLESS you can argue your case for Jaubert styled systems and have used it in a tank SMALLER than a 10.

I have run plennumns with 1/2 inch rise plates and 3 inches of mixed grain sized araganite and oolitic sand in many of my tanks and have had great success (and in 22 other customer tanks that I maintain)

 

Do you see any merit to using a 1/2 DSB and 1/2 plennumn systen in a reef?

 

I have 3 experemental tanks that are set up and have ran flawlessly with this exact style where the DSB is in the front 1/3 of the tank and the Jaubert style intergrated into the back 2/3 of the tanks with only a plumbed 10 gallon sump that houses a turboflotor 1000 skimmer and a small trickle bioball section out of the retun on the skimmer. The oldest tank {54 gal corner bowfront) is 3 years. The newiest is 6 months and is a 29 gallon tank. GAC is in use as well as Seachem Phosguard and a product called "METAL GONE". I am using RODI and Tropic Marin salt and some Aquacraft.net BIOSEA salt blended in with it. Everything is heathy and growing HUGE under a CSL 250W MH with 2 x 32W PC. which is the perferred light unit I use.

 

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DISCUSS !

[tinyreef]

 

i'm not a dsb believer but i don't have exp with them (yet), maybe on the next tank. thing is i haven't heard many stories of them passing the four year mark, then again i rarely keep my grubby paws off the tank that long either.

 

the question i pose for dsb's vs. thinner sb's (i.e. <4") is the ardent insistence upon that dimension. now that dimension may have been derived from some specific experiment but it doesn't seem logical versus applying the same geometric rules to LR. should the LR be a minimal of 8" in diameter then? i've never heard anyone suggest that. LR can house anaerobic bacteria due to 'dead ends' in the rock. sand has the same quality (i.e. tank floor), it's just a question of not disturbing the substrate to oxygenate the areas imo.

 

the aging of dsb's is the recent argument. tangster at about.com is fervently anti-dsb but his thought (i'm assuME'ing here) is that the toxic buildup at the lower areas eventually degrade to cesspool levels and start the crash cycle or OTS. i posed the question whether or not one could bleed off this off like they do at dump sites to bleed off methane. he thought this could work but you'd have some serious dsb smell :x and pvc pipes stuck throughout the tank. plus there's the obvious issue of disturbing the dsb in general.

 

plenum's seem to work. i've never run them past a year or so tho. both times in very small systems, my recent 5g (1-year) and a 1g hex (about 6 mos. total but w/wc's). both systems were doing fine but i just got bored with their respective 'looks'. both times i used a modified ugf plate with a tank divider screen heat staked onto the top. my most recent systems have barely any or no sand tho. :

 

i think you'd have to run a system strictly with plenums-only (i.e. no LR or wet/dry) to gauge them properly imo (e.g. lagoonal or reef/mudflat system).

 

Do you see any merit to using a 1/2 DSB and 1/2 plenumn system in a reef?

 

if you mean run a dsb with a plenum in addition (i.e. 4" dsb over the plenum) i could see the merit in that. the plenum could process the eventual dsb buildup, the two acting in concert. however, i don't believe in separating layers of the sand like a true jaubert does. inhibiting the water flow so much stagnates it too much imo and like i said i'm not 100% sold on dsb's anyway.

 

also the question depends upon livestock (i.e. burrowers).

 

the "additional" chemical filtration you're using may throw off the results for the purists' interpretation tho.

[tgrupert]

has anyone done a blind test of tanks with only sand and nothing else and add nitrate salt? if anyone wants to give me a giant grant and a mail order bride I might be interested, but until then my opinion is you are all wrong.

[tinyreef]

i keep applying for a 'genius grant' for this experiment but for some reason they keep calling me a stupid ass. is there a 'stupid ass grant'? ??? it'd be kinda like Jackass the movie but for research tho.

 

 

seriously tho, that blind test is exactly what i'm talking about. sand-only, sand-only (dsb), sand & rock, sand (dsb) & rock, and rock-only; all of which would be dry to begin with. no LS/LR.

 

it'd probably be better conducted with fish than coral/inverts. you could even get identical litter-mates or hatchlings or whatever you call them, for control purposes. damsels or clowns would be perfect and then just test which format is more effective. you could probably even be able to develop a scale. :

[Keng Yew, Leong]

My 4 gallon runs with a 4 inch DSB.To me it seems fine.I do see some small bubbles trapped in between the bottom of the sand bed.I think it might be nitrogen.What do you think?There are no substrate stiring critters in my tank.I think that my DSB is really anaerobic.

[Christopher Marks]

I've never really worried about sand beds in my systems. I always figured the liverock did most of the work. My 7.5 has about an inch to an inch and a half. It ran for about a year with no sandbed at all, then I added one later. almost 3 years later, it's still going strong. My 15 hasn't been running long enough to say anything definative, but it's been running on a 1.5" sand bed from the beginning.

[tgrupert]

Originally posted by tinyreef

it'd probably be better conducted with fish than coral/inverts.    you could even get identical litter-mates or hatchlings or whatever you call them, for control purposes.  damsels or clowns would be perfect and then just test which format is more effective.  you could probably even be able to develop a scale. :

 

no way, you would add nitrate directly it has to be scientific. this is why I deserve the grant more tghan you

 

 

edit:

 

I just read m,y message and it makes no sence. what I mean is by controlling the exact amount of nitrate you have a more control to make all situations equal.

 

 

the problem of having a sand bed crash is real, but I'm sure we can find ways to prevent it. sand is always moving around in the ocean especaly in the reef because it is so close to the shore.

 

What would be a good way to REALY stir up the sand. and how frequently should it be done?

[LEEWINK]

" What would be a good way to REALY stir up the sand. and how frequently should it be done? "

 

I would not stir it at all, it just defeats the object of a dsb or any sand bed denitrification, might aswell get rid of it.

 

" the problem of having a sand bed crash is real, but I'm sure we can find ways to prevent it. sand is always moving around in the ocean especaly in the reef because it is so close to the shore. "

 

the sand bed crash is all too real, but not all of the natural sea has sand bed circulations, mimicking could be hard too, especially to a given area.

 

If you wanted circulating sand, then rule out denitrification through the bed itself.

 

(Hi dave !!)

 

cheers,

 

lee

 

:) :)

[tinyreef]

rupert,

i never know when you're serious or not. that's an unfortunate side effect from your manic postings.

 

i disagree with the static injections of nitrate. a continual processing of wastes from a bio-cycle and accurately gauging the various medium's effectiveness for that is what we're trying to accomplish. one or two chemical injections can't replicate that imo.

 

lee is correct in his positions. also in the wild you have a significant, if not the majority of the wastes processed by flora.

 

i also suspect microfauna (much of the 'Live' in Live rocks imo) to be a very significant contributor of the filtration process. this is not to be confused with the nanofauna of bene bacteria. only suspicions of mine, no evidence to back it up.

[onthefly]

I've had my 45ga up and running for 4 years. I never do water changes (well, does once or twice count?), just top off and dose (Superbuffer and Weiss Coral Vital LSB booster). I've got a pretty good fish population and feed pretty heavy. My trates are never above 20ppm. Now, although I realize some peeps will say "20ppm!", given that it's a FOWLR with a heavy feeding hand...I think that's good! I've also had fish die (some I found, some I didn't) and never saw a spike in NH3, NO2, or NO3!

 

Specifics: It's a 1"plenum/1.5" sand (small, but not oolite)/screen/then 3-4 inches of sand. It is loaded with critters (worms, cops, and shiat I have know clue about) that hitchhiked in with my rock.

 

Way back when I first started keep a SW tank. I, like alot of newbies, did NO searches, except though wonderful books at Petco. All of which say Undergravel filter ROCK! We'll after setting up my tank, I strutted into my LFS saying: "check out my tank!". Well, I walked out feeling like a bad parent at child protective services and a reciept for a Plenum and a 50lbs bag of sand. That's how I got started. The guy (who I truely respect) said there where 2 ways to achieve denitrification thru DSB's. 1) Plenum and 1-2mm sand 3-4" think on top. Or 2) 1-2" of oolite (the really fine "sugar" stuff). Over the years I though of the exact thing that Dave is testing: "what about a combo of both?" Keep me us informed Dave, also you write it, I'll buy it! Especially, if there will be some colorful ESPI commentary!

 

As for peeps concerns:

 

Tiny: I've never had any fowl smell come from my tank. I know people say it can happen, but I've never smelled it and My system is exactly how you describe (4"DSB over 1" plenum). Specifically, I've heard peeps "rip" plenums because they smell and one book said they release hydrogen sulfide (pee yew), but in 4 years, none!

 

 

Lee, Rupert, and Tiny: You all asked about "turn over". The best way, I found, was using sand sifter critter (thus the screen in my DSB design). Especially the dragon goby! I haven't seen a better sifter than this guy, plus he lives a long time (as compared to sleepers or diamonds). Regardless, from the surface to the screen gets turned over probably once a month by the goby.

[tgrupert]

Originally posted by tinyreef

rupert,

i never know when you're serious or not.  that's an unfortunate side effect from your manic postings.

 

i disagree with the static injections of nitrate.  a continual processing of wastes from a bio-cycle and accurately gauging the various medium's effectiveness for that is what we're trying to accomplish.  one or two chemical injections can't replicate that imo.

 

 

I agree one or two doses wouldn't work. it would be a daily measured dose if not some sort of continual feed. 8if one setup seems to do much better than the rest and keeps the trates at about 0 you can slowly increase the dose to see how much of a load it can take.

 

you nedd to measure it out because in the scientifixc communty "three damsels" isn't going to be as good as "3 mg per day"

[tinyreef]

how come i have a disturbing image of dave peeing into a number of iv drips to add into various tanks now? ???

 

jk dave

 

tg,

thing is your test can be criticized as not a true 'aquarium' test. you may get the 'genius grant' but i'll have the commercial market share.

[tgrupert]

There are WAY to many variables to track in a real aquarium. We are testing for denitrafication, what's so bad about that?

[tinyreef]

i don't understand what variables you're talking about. ???

 

the fish can all be from the same hatching. the foods given can be measured just as accurately from the same containers. the purpose is to monitor the substrate/filter processing abilities versus each other. the only variable may be if multiple fish were used per tank, differing personalities and hierarchy dominances that may play a role in metabolism/consumption.

 

the only uncontrollable variable would be if any LS/LR were introduced. as the various organisms cannot be catalogued. (actually, LS/LR could be used as a control/comparison tank)

[LEEWINK]

ok, so going on chris's insert earlier in the thread :-

 

"I've never really worried about sand beds in my systems. I always figured the liverock did most of the work. My 7.5 has about an inch to an inch and a half. It ran for about a year with no sandbed at all, then I added one later. almost 3 years later, it's still going strong. My 15 hasn't been running long enough to say anything definative, but it's been running on a 1.5" sand bed from the beginning."

 

Just wondering your views on live rock only, and no sand at all.

 

Its not a slant on the discussion from a while ago, just want to hear some views.

 

Surely if the rock does most of the denitrification, then losing the sand bed and having good current around that rock would be better.

 

Also you would need no clean up crew, as there would be nothing to clean up, it would be suspended in the water column, and skimmed off or filtered by the corals etc.

 

There would also be no need or worry about too much algae either, as detritus would not be sitting anywhere for substantial time enough to enhance the growth of algae.

 

Maybe chris can come back to this thread with some more views,

 

cheers,

 

lee

 

:) :)

[tgrupert]

Isn't that like the old style "berlin" system?

[jackobox]

Well I got a few things to say about this whole subject that may raise some disagreements and/or help things out a bi.

 

Testing is a touchy issue in situations like this, fish hatched at the same time won't cut it. You can have the same fish, feed thme the same thing at the same amount, but if the fish doesn't eat 100% then it falls to the bottom and "SLOWLY" decomposes. A fish processing food is going to be completely different than food decomposing on the bottom. Your rates are going to be different which means your nitrate loadings will be different at different times, so drop the fish idea.

 

In order to do this test everything has to be the same or in a comparison to each other. You could throw say 20 lbs in a 5.5 gallon and say 5 pounds of rock in another one, (your rock shape, density and porosity all come into affect and ruin the experiment), you'd have to dose diluted ammonia or nitrate and does it like Kalk, but 24 hours a day.

 

You'd then have to test each system like this, berlin, plenum, DSB and take your results from there.

 

One last thing are the bubbles under the gravel you see through the glass. Has anybody ever noticed something funny with this?? What I'm talking about is the fact that you can disturb the sand or gravel next to the glass and tons of bubbles rise to the surface. Go to the center of the tank and try the same thing, there's nothing there. What I'm saying is those bubbles in the front of the tank are from that nicely colored algae, the only place where it CAN grow that deep is next to the glass where there's light. I want someone to try this and tell me what happens, maybe it's just my tank but I have a sneaky suspicion that things are not what they seem.

 

-Jonathan

[onthefly]

I've never seen the "bubbling" effect the peeps talk about associated with DSB's and Plenum's. That being said, I do have a rather vigorus sifter and perhaps a large portion of the bubbles are not allowed to accumulate. Regardless, I do have a good amount of denitrification goin on in my sand......but no bubbles!

[tgrupert]

cover up the sand with construction paper, bubles disapear like magic.

[Dave ESPI]

bubbles of Nitrogen good.

Bubbles of Hydrogen sulfide Bad.

 

I run 1/2 dsb and 1/2 plennumn tanks now for a few customers.

The best of both worlds. Perhaps I am onto something here.

 

time will tell.

[skylsdale]

First of all, I think there needs to be an agreement as to what constitutes a DSB. The purpose of a DSB is to help aid in the denitrification process, which can only happen when anaerobic areas occur within the sandbed, providing an environment for this process to take place.

 

I have seen only a handful of nano reefs that actually had sandbeds deep enough for these areas to establish themselves. For some reason people start to think of DSB depth as proportionate to the tank size, thinking that a 3" sandbed in their 6 or 10 gal nano is a DSB. If 3-4" isn't deep enough in a larger tank for anaerobic areas to establish, then why would the rules change in a smaller tank? So for all intents and purposes, a nano would still need around 5-6" of sand in their tank to really ensure the presence of anaerobic layers within the sandbed. Some people say that 4" is the bare minimum (using sugar grain size), but even that isn't guaranteed to work.

 

Also, some say that there needs to be a certain amount of surface area on the sandbed for there to be a "workable" amount of anaerobic areas. I believe this notion comes from a certain "doc" on another board, and I would search over there for the exact principles of this. But in general, even a 6" DSB in a 20 gal tank may not work because there isn't enough area to provide efficient anaerobic areas.

 

As far as all the people who are "anti-DSB"...most of them were probably at one time "anti-anything but UGF" at one time, too. Things change and new methods are discovered, although many people stick religiously to their "one right way" of doing things. Personally, I wouldn't even consider dropping a plenum into one of my systems. Why? Not my style or way or running a system. Does that make my reefkeeping skills inferior? Unfortunately, many would argue that it does. For those of you who "go the way of the lemming" and believe the soothsayers about the toxic buildup of "such and such" things in the sandbed, leading to a complete destruction of a system, I would challenge you to figure out for yourself whether you agree with this. Heck, one of the biggest proponents of DSB's over the last few years has now recanted and said that they may cause problems. But keep in mind, all of this is PURELY ANECDOTAL AND SPECULATION. People have yet to come up with any somewhat solid or concrete evidence that this is true. However, there are people who have succussfully kept tanks with DSB's for the long haul: I believe Rob Toonen has had a DSB in one of his systems for over 16 years now. People give various reasons as to why DSB's may be the end of peoples' systems, but it's all still pure speculation: from toxic gases being released to synthetic salt mixes introducing toxic metals to the systems which bind to every particle in the tank...slowly bringing our system closer to its end with every water change. The evidence of these suppositions? Well, there isn't any....but it COULD be a possibility. No one has yet to positively confirm or deny the long term success of a DSB in a captive reef system, and they have yet to accurately tie it to the cause of "old tank syndrome."

 

In the end(after going off on somewhat of a tangent), I am in the same school of thought as Mr. Marks here: there's really no purpose for DSB's in the world of nano reefs. If you have a decent amount of LR and appropriate stocking levels and maintenance schedule(according to the needs of your tank) then you'll be fine.

[tgrupert]

Originally posted by skylsdale

First of all, I think there needs to be an agreement as to what constitutes a DSB.  The purpose of a DSB is to help aid in the denitrification process, which can only happen when anaerobic areas occur within the sandbed, providing an environment for this process to take place.

 

very good point. we need some sort of ISO 9001 standard for sandbeds so everyone knows what everyone is talking about. the other way would be to create a notation to explain the different layers or plenium, screens, and sand material as well as grain size.

 

the trick is getting everyone to use it. somone could easaly create a little aplet that decodes it for those not in the know

 

you would type in my sand bed is {URL=http://nano-reef.com/sand.php?s=p.20a0.scr.70a02]p.20a02.scr.70a02[/url} oviously I wouldn't use { or }

 

p.20ar0-1.scr.70sd might mean...

plenium

20 mm of VERY fine aragonite

screen

70 mm of very fine to smallish aragonite (sizes 0 to 2).

 

 

oviously it would need to be much more simple.

sand would have a number to denote depth in mm.

followed by a letter to denote matterial. (a for aragonite, d for dolomite, m for mud and so on)

5 different sand grades from super fine to crushed coral makes sence. you could show mixed grades with several numbers. for instance grades 2 through 4 could be 234 or 24. maybe it could be more simple if it was XS, S, M , L, CC.

the period seperates each layer.

 

I probably sound like a programer, well I am tough ######. we could even have it auto decode with {sand}p.20a1.scr.50a03.5acc{/sand} and get some PHP script on the server to auto decode it.

[onthefly]

Peeps are looking for the answer to "how deep does my DSB need to be" question in a trail and error type of arena.

 

That being said, I have 3-4" of non-sugar sized sand in a 45T (i.e. lower surface area) with a plenum inside that and I have plenty of denitrification (even with as little as 1" of sand above the plenum...thanks to my goby). The guy I got my plenum from uses 2" of oolite (sugar sized grains - 0.3 to 1.2mm) in tanks under 28ga and 1" in 10ga and smaller, and he gets "boo koo" denitrification.

 

So, like skylsdale said, you can't make blanket statement about what will work and what won't! What matters is the "anaerobic" surface area, not how thick you DSB is. Now for the kicker, most reefers have some serious water turn over in their tanks (i.e. Rio 800 on the fuge and a Micro 404 in the main ~300-350 gph turnover in a 10ga). How can you get good anaerobic zones with Niagra falls flowing in your tank? So, if peeps are looking for denitrification in their substrate, its a balance between circulation, LR amounts, sand depths, and sand composition.

[Xavier]

maybe this is just me, but I hear lots of people saying "I get lots of denitrification from my sand bed", or just the opposite... how exactly are you determining this... if it's true that LR handles the lion's share of denitrification, then you'd imagine that a properly balanced system would have no need for a sand bed at all, or that you'd be able to test your sand bed, and in theory, little nitrification should be occurring... I would then imagine if sand beds were efficient denitrification zones, we wouldn't place such a large dependance on live rock...

 

if we were to look at a coral reef in the wild, would we say the water they subsist off of is primarily filtered by the sand (I'm just throwing that out there - I truly don't know the answer)?... I'm not denying that the sand has a beneficial role to play in the oceans, but what are the numbers to say that this same sand setup in a tank provides the same level of water quality output found in the wild... I completely agree that a controlled study should take place to determine this...

 

we have to keep in mind there are millions of square miles of sand bed in the ocean to the relatively small amount of coral reefs... for this to be as similar at home, we'd need a HUUUUUGE tank, with one chunk of LR in the middle with some corals on it...

 

I think we tend to see our little reefs as just that... a minature reef in a minature ocean, instead of a piece of something larger... in reality, my "reef" would really just be an outcrop on some other massive reef...

 

Now, if we want to start talking about the livestock we want to keep in our tanks, some of these require deep sand beds... gobies, stars, cucumbers, some snails, etc... are they a sufficient enough reason to have a sand bed? possibly... many of which subsist off of the bacteria, algae, and detrius found there.. but with those, you loose the anaerobic areas which would make that sand bed an efficient denitification factory...

 

Personally.. I have a 3-4" sand bed.. not because I believe in it.. but because I'm starting out with my SW hobby, and originally told "You've gotta have live sand"... I have since started a small 10g without a sand bed... using all of the same water, salt, additives, etc, I can say my 10g sand-less tank has had fewer problems then the larger 25 w/ sand bed... not very scientific, I know.. but I'm starting to ask myself what the sandbed provides to the denitrification process, that the live rock does not...

 

aside from food and cover for bottom dwelling critters, I'm not sold...

[LEEWINK]

"Personally.. I have a 3-4" sand bed.. not because I believe in it.. but because I'm starting out with my SW hobby, and originally told "You've gotta have live sand"... I have since started a small 10g without a sand bed... using all of the same water, salt, additives, etc, I can say my 10g sand-less tank has had fewer problems then the larger 25 w/ sand bed... not very scientific, I know.. but I'm starting to ask myself what the sandbed provides to the denitrification process, that the live rock does not...

 

aside from food and cover for bottom dwelling critters, I'm not sold..."

 

well said again, a good project with a beneficial outcome, do you find your corals like it better too, and is your tank seamingly cleaner by the non-use of sand - ie detritus building and algaes ?

 

cheers

 

lee

 

:) :)