Deep Sand Bed (Max Depth?) - 05/16/05
One article reads: 
"The depth of the bed (and particle size) are critical to provide the correct conditions. If the sand bed is not deep enough, and the oxygen level does not drop enough, the sand bed will produce nitrite from the nitrate. A disaster. Conversely, if the sand bed is too deep, the entire bottom of the bed can turn anoxic and produce sulfur dioxide. If this happens the affected sand turns black. If this black area is disturbed or sampled it releases the characteristic rotten egg smell. This chemical is of course toxic" 
What is too deep? what is the max a DSB can be?
<Is this from the WWM Website? <<Is assuredly not. RMF>> Do have a read here and at the related links in blue at the top of the page - http://www.wetwebmedia.com/deepsandbeds.htm  Regards, Eric R.>

Deep Sand Bed Height - 1/26/04
Hello there, <Hi>
I am constructing a 15 gallon sump for my 29 Tall aquarium. The sump will have three compartments, the first will be for the run-off / skimmer, the second will be a 10" Wide x 12" Deep (or 120 Square Inch) live sand area, and the third will be for the return pump.
I have heard that 6" was a good depth for a DSB. <Yeah, but not exactly the rule of thumb> Can you tell me what you recommend for my set-up.<4-6 inches is fine. Be sure to add some quality live sand from some other aquarist's tank or from a trusted LFS. The bag stuff just wont quite do it. Not that it is not a good product, but not as full of various inverts that are beneficial to the sand bed> If I didn't have to go 6" deep, instead using a 4 to even 5" deep DSB, that would help my design much better. <Then go for it. No worries. I think you will find the benefits somewhat the same. Quality over quantity> I want to make sure that I will get the same benefits from a 6" DSB though. <You will be fine. Happy reefing! ~Paul>
Thanks a bunch!
Aaron

Deep Enough Sand Bed?
Hi guys,
<Scott F. your guy tonight!>
after going through all your DSB pages, I've decided that I'm going to add one in to my established 4ft tank. I am currently half way through my project, and have hit a bit of a snag which i hope you guys could help me with.
<We'll try!>
I've also bought a refugium, which I'm adding to the system as well. Originally, I was only going to the DSB in the refugium, but decided to put it in the tank, because I knew that I would always be regretting it. So, I get home after buying all the very fine sugar-size sand I could get (I've found only one place that gets it, and I bought it all), put all the fish in the shiny new refugium, took out my old gravel, and put in the sand. The problem is that I only have enough sand for about 3.5inchs deep, and can't get any more for at least a month. My understanding is that this is
not deep enough.
<Well, it's not a "deep" sand bed at this depth- but it is workable>
I'm not really sure what to do, but I see the below as my options:
1. Leave it as is (with 3.5 inches). I remember seeing that cos its finer, doesn't need to be as deep, but not sure of the minimum.
<Well, there are many thoughts on this. As I mentioned above, it can be useable. You can always add some additional depth as you locate the substrate>
2a. Add some more sand that would be larger grained, about 1-2mm, and mix it in with the sand.
<Can be done, too>
2b. Put an inch or so of the coarser sand OVER the fine sand.
<A possible solution>
2c. Put an inch UNDER the fine sand. This will be a bit trying tricky, and will cause another sand storm.
<I wouldn't do this>
3. Use all the fine sand to make a 6-8inch DSB in the refugium. Main tank  has a foot print of 48x14, refugium would have a DSB of 23x12.
<A viable option...>
4.Wait a month for more sand to come in.
<That would be my call>
What would recommend?
<I'd go with #4, myself>
Also, does the sandstorm affect the fish?
<Could irritate some fish or inverts, but I wouldn't be overly concerned if you're careful>
Thanks in advance. My system is currently pulled apart, and I'm sort of in panicky mode, because I don't know what to do...
<Don't panic...You'll be fine leaving things as they are for a while. Just obey the common sense rules of husbandry, and you'll be fine! Regards, Scott F.>

Deep Enough Sand Bed? (Cont'd.)
Hi Scott F., thank you for your response, but i have a follow up.
<Ask away...>
I was in a rush (i.e., my tank was pulled apart), and decided to go ahead option 2c below, where I now have 4-5 inch DSB, with about 2 inches of more course aragonite (1-2mm), and on top of that, 2-3inches of very fine reef sand. You said you wouldn't do this, but unfortunately, i already did. Is this something bad? Should I redo it? the sand is very fine and blows around easily, should I put another inch layer of the 1-2mm aragonite over the top, adding an additional layer?
<Actually, I don't really see any harm in this. Yes, DSB "purists" will want a DSB constructed exclusively of sugar fine sand, but I personally have not had problems in mixing different grades of sand together. >
I'm not sure why you don't recommend it, I thought that the finer sand was recommended for infauna growth and movement? Or was it not recommend because of the storm it would produce?
<Well, I didn't recommend this because it seemed to imply that you were going to disturb the lower level of fin sand in the process. My concern was that you would seriously disrupt the very processes that you are trying to foster in a DSB. Organic material can be released into the water en masse with such a disruption...Sorry if I didn't fully explain my concerns...>
Thanks.
<My pleasure! Regards, Scott F>

Deep Sand Bed
>Greetings from Northern California,
>>Greetings from Southern California!  Marina today.
>I'm currently setting up a new 18 gallon reef tank, and currently have a little over 2" aragonite substrate (.5mm-1.7mm). There is nothing in the tank right now but this, and water mixed at a SG of 1.026. Reading your articles about the benefits of natural nitrate reduction by using a sand bed at a depth of 4" or more has convinced me to try and implement this for the great long-term benefit it would provide.
>>Great!
>I would have gone with a really fine substrate, but have been unable to find it in my area. One of your articles mentions that at larger grain sizes, a greater depth is required. I wanted to know if I can use the grain size I mentioned above to create an effective DSB, or if I should try getting some fine aragonite through the mail and then adding that along with the existing substrate.
>>Your biggest limitation is the tank space you'll lose going deeper, but it most certainly can be done.  I would suggest 5"-6".
>In either case, I would like to know the depths I should be aiming for.
>>DSB's seem to work best when they're at least 4", although you'll find/meet many who go as shallow as 3".  The whole point is to create a sufficient anoxic area, and because the tank is almost considered a nano, you'll have to make up partially the surface area with depth.  I think you can achieve admirable results using what you have at a depth of 5"-6" (doesn't have to *all* be that depth), Brian.  I do hope this helps, and best of luck!  Marina

DSB Questions
Mr. Fenner,
<Hi there>
I am contacting you in regards to DSBs.  I have a small reef website, mainly informational, with the intent to promote tank raised frags, tank raised fish and aquacultured LR.  I have also developed an interest in helping beginners avoid those mistakes we all make as newbies...
<Or "oldbies" for that matter>
I have a free newsletter I send out, and am thinking about doing an article on DSBs, and I would like comments from some of the experts...  So if you wouldn't mind, would you please take just a moment to answer the following question:
"What would you consider to be the one most important factor in starting, and/or maintaining, an effective DSB?"
<... just one? Okay, the depth of the material used... though (of course it's make-up, particulate size, uniformity... are important as well. But in my estimation, more folks "fail" with their DSB's due to a lack of depth of substrate than any other single factor>
If you have the time, I would love to have any comments you have about my site.  Please feel free to stop by.
<Oh, yes. We have a link to your site. Good show. Bob Fenner>
http://www.fragexchange.com
John McCann
FRAGexchange.com

Substrate depth
Hi guys,
oops.. and gals :)  <howdy> Just wanted to thank you for all the help you have been able to provide it the past.
The things you all do for the hobby are immeasurable.
I was planning on a DSB of 4-5" in my 75G reef tank with CaribSea Aragamax (1-1.7mm size), but let me know if there is something better.
And if I used a smaller grain size could I make a shallower bed and still be able to achieve an anaerobic area to reduce nitrates? Or would this not be recommended?  Thanks once again for all your help and knowledge.  <This is a fine sand to use.  Your sand bed should be at least 3.5” but 4-5 would be better.  As for the smaller grain, I would stick with the Aragamax because anything too much smaller would just be mud. Cody>
Best Regards,
Jeremy

Deep Sand Bed and Aiptasia control
Hello,
<Hi Rodrigo, Don here today>
I have no words to appreciate all the benefits everyone can get here in your web site. Thanks a lot.
<Thank you, it is an honor for me to be a small part of this>
I have very high nitrates (huge)  in my reef tank. Everything looks fine with the fish and corals but reading here I just notice that my sand bed is in the range where you say is not good (1" to 2"). My tank is 29gal (the base 30" x 12"). I am planning to increase the deep to 3" or 4" using the Southdown Sand. Is this sounds good?
<I would go 4+ while you are at it.>
I am planning to do a 50% water change this weekend that I haven't done since 6 months ago.
<Yes, likely a major part of the problem. If you can, changing 3-4 gallons weekly will do wonders with the water quality>
May I ask you how to mix the new sand with the existing one? I thinks some of the actual sand is fine but also some it is not that fine (not coarse either). Or should I put the new sand over the old sand? Maybe I should do the opposite? Right now I have a couple of Maroon Clown fishes and a bicolor Pseudochromis so I think these guys are hardy enough to resist some chemistry changes. I also have skimmer, AquaClear with Polyfilter and Chemipure.
<If the existing sand is < 2mm then I think I would go right over the top, a little at a time.>
I have a second question: I have some Aiptasia, like 10 of them. One month ago I tried to introduce a peppermint shrimp but the Pseudochromis bicolor bothered him until he died. Should I remove the bicolor from the tank? The Aiptasia looks very ugly.
<Check here for more info on controlling Aiptasia: http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/aiptasia/aiptasia.htm Hope this helps, Don>
Thank you very much, Rodrigo.

Depth of DSB 7/7/03
First, Anthony and Bob; I'm enjoying your new book. A lot of very interesting reading. Anthony, thanks for the inscription.
<very welcome my friend... thank you :)>
In it you bring up that 3 inches of sugar size sand is the min. for NNR. Do you have any studies that back that up? Want to know for when I am talking to people about their tanks.
<Dr Rob Toonen has released some prelim data on such matters... will have full report soon I hear. Other data exists (some of the original work) from French academic aquarists in France dating back to the late 1980's/early 1990's (Jaubert, Ounais). To be honest though... I'm really speaking from a decade of practical experience. I used 48,000 lbs of the sugar fine aragonite sand for my mariculture facility. Heehee... this combined with similar reports from colleagues led me/us to the statements>
The other question is about the "half-life" of 18 to 24 months you bring up on page 36. I've not seen that in any of my tanks with aragonite DSBs.
<indeed... 'tis because of the commonly variable pH that works in the favor of aquarists in this case (not dissolving the sand consistently/fast enough... but at the expense of dissolved bio-minerals)>
I have a number of tanks with 3 or more inches of aragonite that are 2 to 3 years old and do not seem to show that in any of them.
<without a Ca reactor, such tanks usually do not have fast coral growth either (scleractinians). No worries at any rate>
Could this be caused by having too many borrowing detritivores or animals like pistol shrimp? Thanks, Ray Pollett
<no my friend... really just a matter of adequate water flow and various faculties to dissolve the material. A matter of grain size too if larger. Kind regards, Anthony>

DSB 29 gallon
I am planning on converting my 29 gallon FOWLR aquarium to a reef type aquarium. I would like to replace my current crushed coral substrate to a sand bed. I am considering a DSB, however I cannot decide whether this is practical for this size tank. If it is practical, what depth would you recommend?
<DSB stands for Deep Sand Bed, with the deep being the operative word here. Four inches or more is our standard recommendation.>
Thanks, Mike
<You are welcome. -Steven Pro>

DSB for a 29 gallon: How many bags of sugar-sized sand?
Thanks for the quick reply.  I decided to use CaribSea Aragamax Sugar-Sized Sand.
<That's what I have in my tank.>
It comes in 30 lbs bags.  About how many bags will I need to obtain a 4 inch depth in a 29 gallon?  
<It's hard to say. Visually compare the size of the filled sand bag to the overall size of your tank and make a guesstimate. If I were you, I would buy two bags and tell the shop owner you may need to bring one back unused. Most LFS are pretty god about these things as long as there is a clear understanding up-front.>
Thanks again.  Mike
<You're welcome! David D.>

Debate... (Deep Sand Beds...)
Hi Bob...
Thought I'd get your opinion on something that seems to be of some debate on the http://wwwsaltwaterfish.com message board.
<Okay>
The deep sand bed. How deep? 
<A few to several inches in most hobbyist set-ups... depending on grade, composition/make up, how spherical, desire of use... chemical, habitat...>
Sand sifters or no sand sifters? 
<I say with in most cases>
The debate is about the bacteria that exist within the DSB that help eliminate nitrate levels. Some say that sand sifters are good and help mix things up...others say that sand sifters disturb the colonies of bacteria that need an "oxygen less" atmosphere to survive. The anti-sand sifters also claim that disturbing the DSB might release toxins into the tank. Do you have an "official opinion" that I could share with this group?
<Yes... that all these statements are valid within degrees... most all erstwhile sand sifters only move about the upper centimeter or so of material... no big deal... and as some folks state/d of benefit as well>
Also, thanks for tipping me toward the CPR site to look at their HOT refugiums. I'll be getting one of those in the next couple of months.
<Good designs... the owner of the company (Suk Kim) goes to a lot of the hobby venues (WMC, MACNA...) and listens carefully to what folks are looking for, having troubles with... in designing, offering new products. Smart>
Still have to put the rock in the tank...it's almost done cycling.
Hopefully all levels will be 0 this weekend so I can build my reef. The empty tank is getting a little dull as far as decor in the living room :-)
I've also recommend the CPR refugiums to others on the board mentioned above. Since I can't really give my own advice yet, I will have to site yours. Seems to be a hot topic.
<Good to find folks thinking, debating.>
As always, your advice and guidance are appreciated!
Kind regards,
Misty Johnson
<Be chatting. Bob Fenner>

DSB & "Stuff"
Greetings all,
I just completed the move from New Hampshire to California....it was not an easy task. I am setting up my 48 gallon bow tank and went with a 5 inch deep sand bed (oolitic aragonite)...lord ONLY knows where the fish are going to fit with all that sand. The effective space is reduced to about 15 inches. But the nice thing is that the "bottom" is closer to eye level so viewing critters should be easier on the back. On that subject, I had an interesting experience when fly fishing last month that made me think of the DSB discussions. There had been a fire in the Sierras and the stream I was fishing was full of sediment, about 3-4 feet deep. I stepped in and sank up to my freakin' neck and (after I realized I wasn't going to die in quicksand) I notice the distinct smell of sulfur! It was bubbling up from the bottom of nature's deep sand bed, you could see it rising in bubbles all over the place. It was neat to see a live working model of something we always bandy about here.....so I guess if you go with a 4' DSB you might really have a problem in your tank <grin>.
<I have seen 12" sand beds that did not produce Sulphur gas. At a certain point though, you are not really any more productive as far as denitrification or critters. I aim for 4-6" myself.>
By the way, my wife still insists that the bubbles were coming from my waders.
Anyway...on another note, I noticed that the house I'm in gets up to 86 degrees on REALLY hot days (only a few hot days a year in Silicon Valley
luckily). There's no a/c in the house. Do you think I might need to spend a zillion dollars on a chiller?
<I would much rather spend the money on AC. Even a one room unit is more cost effective and makes watching the tank more enjoyable.>
Also, I'm on the hunt for some decent live rock in the south SF bay area so if anyone knows of a good retailer I'd be grateful for a referral.
<Do ask for recommendations from online message boards. Ours is at http://wetwebfotos.com/talk/index.jsp>
Enough rambling for now. Thanks so much for all of your help. Don't ever quit, I won't know what to do. Wes
<And neither would we with all the free time. -Steven Pro>

Deep Sand Bed/No Sand Bed/Shallow Sand Bed? 7/5/05
In planning a new 90 gallon, quick question or two - Do DSBs really, truly play a significant role in nitrate reduction.
<They have been proven to perform this function, if properly implemented and maintained.>
Some folks seem to downplay them, at least in part pointing to their hazards (crash, etc.) and as being a detritus trap.
<A possibility if poor husbandry techniques are employed. The "nutrient trap" idea is often brought up in hobbyist discussions and message boards. With good maintenance and overall husbandry techniques, the deep sand bed can be an effective ally in natural nitrate reduction for many years.>
Would it be a bad idea to set up my 90 with say only a 1 inch sugar-size sandbed (more for aesthetics) so as to facilitate keeping the bottom clean in lieu of some nitrate reduction?
<If you are going to use some substrate just for aesthetics, then you'd be better advised to go with 1/2", in my opinion. One inch is too shallow to foster denitrification, but possibly too deep to be fully aerobic. A sort of biological "no-man's land", if you will. In summary, it's better to go really shallow.>
I'm guessing you'll always come down on the side of the DSB (but not sure)?
<Well, I am truly supportive of both DSBs AND Bare bottom techniques! It really comes down to husbandry. I have maintained both with success, and many other hobbyists have as well. My current reef system is actually bare-bottomed. I elected to go with bare bottom simply because I am employing a tremendous amount of flow, which would send sand all over the place! It was not a choice I made for any other reason, really, but it is working fine. I personally do not like the aesthetic of a bare bottom, but you do get used to it after a while.  My tank chemistry and overall water parameters are great. I will probably ultimately use a very shallow (like 1/4" to 1/2") bed of medium grade substrate, just for aesthetics, in my system. I might add that I am a water change fanatic and an enthusiast of good husbandry techniques. There certainly seems to be a lot of backlash against DSBs on some of the hobby message boards of late. Granted, no one technique works for everyone all of the time. However, I am not so sure that I agree with or understand all of the things being said about bare bottom technique (like the idea of "wet skimming", which to me seems like a strange concept...Why not just do regular, old-fashioned water changes, and pull out dark skimmate regularly? I'm sure there is a well-thought-out reason for it, but I just don't quite get it.). Like any methodology employed within the hobby, there are some fine hobbyists on the cutting edge researching and sharing their findings, and their findings do warrant your attention, with the usual caveats about employing a healthy dose of skepticism. I do take some degree of offense with those who say that bare bottom or DSB is THE way to go. In my opinion, a DSB is excellent as well. If detritus is allowed to accumulate, bioload is excessive, and husbandry is not up to par, neither system will be effective. Of course, I am convinced that those hobbyists who are successful with bare bottom tanks could be just as successful with DSB driven systems. Sorry to go out on a soap borax, but I think that it needs to be stated that both concepts can work, IMO.>
If I go DSB, would 6 inches of sugar-size be satisfactory to see real benefit?  
<Six inches should do the trick.>
Under the 1 inch sand scenario above, accompanying that plan would be a 20 gallon refugium underneath (perhaps with 6 inches of sand there) and a separate sump of about the same size for a good skimmer such as a Euroreef or AquaC 180.  With this setup under the tank, would the 1 inch sand bed in the tank be good?  Advisable?  Not so smart?  
<The idea sounds fine, but I would opt for 1/2" or less in the display, myself. Either of the skimmers that you mention would be great, BTW!>
Just trying to be thoughtful in my planning.  Thanks for your time.
<My pleasure! Sorry for the essay, but I think that there is much on the subject that we all have to learn! Do share your findings, regardless of which way you go! Regards, Scott F.>

LED Lighting, Sandbeds, Worms?, and Starfish legs 7/7/05
Hi!
    Four quick questions:  1) What's the latest on LED Lighting for reef tanks?  Any major developments?  I bought an LED flashlight a year or so ago and was amazed at how much light they can put out with relatively low power consumption and seemingly little heat.  Seems ideal for our hobby. < There is no update here yet.  But Tullio is going to be talking about this at MACNA this year.  So far they are the ideal light source that isn't available. > 2) What's the latest philosophy on sand bed depth?  Last I heard, everyone was talking four to six inches.  The other day a guy at my LFS said deep beds are out ("they're fine for three or four years, then they crash.") and one inch is now the preferred depth.  < I've always been a fan of 3 inches, and still think that is the most recommended option out there. > 3) My small salt water tank has been running for about three years (oops! and it's got a three inch sand bed....see question #2!!!) and is doing great.  < Then don't worry about anything. > When I put in any kind of meaty foods such as freeze dried brine shrimp, dozens of almost clear hair-like filaments one to two inches in length come out of the live rock and sand, groping for the food.  What the heck are they?  Nobody at the LFS seems to know exactly what they are, but everyone thinks they're a good thing and indicate a healthy tank. < I agree.  Don't worry just enjoy. > 4) A second sand-sifter starfish in my tank is losing it's legs.  The first one unfortunately didn't make it.  Is something eating them? < More likely a starvation problem.  I don't recommend them in a reef tank and I think they are hurting your tank.  I wouldn't be surprised if this second specimen is suffering from the lack of food due to the first specimen. I'd either directly feed it, or remove it. > What's going on?  I have some red-leg crabs, one emerald crab, Turbos and some Nassarius.  Fish are Chromis, clown and a lawnmower blenny. Nothing aggressive. Water quality, temp, etc. is all within acceptable limits.
    It's amazing how many "experts" there are at the LFSs.... but everyone has a different answer!  This website is a fantastic service.  Thank you guys so much for donating your time and your expertise to his hobby. < You are certainly welcome. >
<  Blundell  >

Is it deep enough? 8/14/05
Hi
I would like to know if going DSB 4" to 5" in a 125 gal  reef  tank would be sufficient to bring down nitrates to acceptable levels?
<Will help>
I have intakes spaced 4" from the bottom and to put  a 6" bed might complicate the water flow.
<Can, could likely be "tee'd up"...>
The intakes also are located in the middle and at the top water levels. Also, Can I keep my orange spotted cleaner goby?
<Mmm, likely so>
Will he disturb the bacteria bed?
<Likely not much>
Are Nassarius snails good?
<... yes>
What can I do to keep the detritus levels down without disturbing the proper bacteria bed? Thanks for your input............. David
<Please read here re:  http://www.wetwebmedia.com/deepsandbeds.htm
and the linked files above... Bob Fenner>