# deep sand bed



## Flear

i have ideas for setting up a deep sand bed

there's no 'traditional' about a deep sand bed, especially in a freshwater tank, in a marine tank they are critisized more than tested. more-so than in tropical tanks

the theory behind a deep sand bed is to provide a sufficient anaerobic layer that has no access to disolved O2 (the areobic layer has consumed available O2 in the substrate). the anaerobic layer must gain it's oxygen by breaking down nitrates and nitrites.

in turn deep sand beds give off lots of CO2 that moves back into the water column

typically a deep sand bed is more than 3" of fine sand (pool filter sand is perfect) with water flowing enough so all areas are equal in the tank

to test on a 30 gallon tank using goldfish and no plants, after typical tank cycling is done, without water changes afterwards. testing regularly, if if nitrates, ammonia and nitrites remain safe and stable. what is a good lenth of time to consider if this is successful?


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## Diana K

I would also test the oxygen level in the water. 

I would run this a minimum of 6 months. It may take half that time to develop a good anaerobic population in the DSB.


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## Jonnywhoop

a self sustaining enviroment? sounds interesting. ^I agree with Diana about 6, it would definitely take a while.


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## Flear

i was thinking the same, (6 months), just wanted more input than just a personal guess
going to up the sand depth, 4"

now i just need sand and a place to set it up, ... landlord won't allow 2 aquariums  or i suck up and see what i can get away with.

jonny, yup, want to find out 2 things, ... what such a sand bed is capable of handling without plants, and how deep each layer in the sand bed is (estimated)

plants would improve what the aquarium could handle, but throws the test off to see what the sand itself could handle


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## skylsdale

I wouldn't say they are criticized more than tested (I was active in the reefkeeping hobby when they were the "only proper way" to set up a reef tank). The early adopters and testers, however, after around the 3-4 year mark of having proper DSB's (we're talking 6" or more of sugar-grain oolitic sand substrate) started dealing with really bad nuisance algae issues. One thing they noticed is that much of these algaes seemed to appear on the glass and liverock at the surface of the sandbed and work its way up. This led many to believe that the DSB was like a sponge for the nutrients...but like any sponge, it could only hold so much until it became completely saturated...the result in a reef tank was that it simply couldn't sequester any more nutrients and they were then remaining in the water column.

Dr. Ron Shimek (who came up with the idea) said that people simply hadn't set them up right--he said that large numbers of microfauna needed to be in the substrate in order to help break things down, keep certain layers churning, etc. He said his system was a success and that his DSB-based tank at home was doing fine...although he refused to post pictures of it.

3-4" of oolitic substrate was the absolute bare minimum depth, and even this wasn't guaranteed to provide the proper depth for a decent anaerobic layer to form. This was, however, the max depth many people even attempted. 6-8" was recommended as a minimum for possible success.

In a freshwater application it MIGHT work...but you also have plant roots that are pulling oxygen down into the substrate as well. However, they will most likely remain above any anaerobic areas. I would probably look into 'old fashioned' plenum systems and go that route to save on substrate depth.


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## Octavusprime

I believe methane not CO2 is produced in these anaerobic conditions... Respiration and fermentation creates CO2. One requires oxygen the other requires sugars.


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## Flear

following a lady's thread on another forum, she was running 2.5" in a tank she said had about 3x the general 1"/thumb rule. shoving dead critters under the gravel to decompose and add to the nutrient base for the plants. her ammonia and nitrate/nitrite was consistently zero or near zero from what i remember her talking about.

for critters in the sand bed, Malaysian trumpet snails, blackworms, can't be certain about others. had lots of plants.

water changes only for medication treatments.

a reef/marine tank is so different from a planted tank i think they're hard to really compare. plants change so much of what is going on.

i've also heard a lot of conflicting info about plant roots. to they suck in O2, to they maintain O2 around their own roots by their own processes. too much conflicting info in the hobby to take any of it seriously, ... so i need to start searching for university and research institutes to find out reliable info.

but the lady in the other forum noticed that far into what is considered the anaerobic layers where there should be no ready source of available O2, the blackworms were clinging to the roots and quite happy.

Skylsdale, thanks for the input though, ... and thanks for the oolitic sand suggestion , definitely looks rounder than pool filter sand.

not giving up on the deep sand bed, but you've given me lots to think on. and somewhere i do believe i heard mention of changing the sandbed after 5 years. if it's for algae purposes, i'm going to remain skeptical. if i ever do have a marine tank i want to make sure it's plants in it though. ... algae in a marine tank, ... if i get that far is going to leave me near clueless about controlling it. from the little bits i've come across (not searching for) algae is rather rare in a reef/marine tank. going to be as hard to find out how to prevent it from taking over if it ever does show up.


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## Flear

octavus, ... true enough for terrestrial life, ... aquatic life seems to operate by it's own rules. that's going to require more research and searching to find out where the truth and the myths are seperated.


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## Flear

Oolite search, ... sounds like that would throw off nutrient & PH balance in freshwater tanks


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## Octavusprime

Well the creation of methane does happen in anaerobic freshwater environments. There have been reports of large methane bubbles killing off fish in lakes and ponds. I periodically poke my substrate and release these gases in my planted tank since this inhibits proper root growth.


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## Flear

following a deep sand bed thread on another forum, a diagram lists methane.

according to the diagram as it rises up and diffuses through the water column it's expected to combine with oxygen and produces CO2 & water.

granted, what "should" happen & what does happen are 2 different things.

how often do you get bubbles ?, what do they smell like ?, how fine a grain is your substrate ?, or is it more muddy and silt-like than sandy ?


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## Octavusprime

I use a sand and Eco complete bed. It is 2inches in the front and 6 inches in the back. I'd say monthly I can stir up some bubbles with my forceps.


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## jhays79

I have sand in one half of my tank. I'm never too thrilled when I feel how compacted and tight it gets. I picked some vals out of it yesterday and it's unbelievably tightly packed.


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## Flear

jhays, any critters in there to turn over to top layers of sand for you ?, would keep that looser


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## Flear

*Deep Sand Bed Experiences*

looking for peoples experiences concerning the Deep Sand Bed.

problems i've heard presented are nutrient buildup and fears of Hydrogen Sulfide.
i'm aware of those concerns.

internet and forum searches for info and possible problems have reached a dead end culminating in the above mentioned concerns about why they are not a good thing to use in an aquarium (any aquarium - freshwater and saltwater)

waiting for the new year when finances are again available (welcome to Christmas expenses)

asking ahead of time so i can get an idea what problems to expect and what can be done to resolve those issues.

curiosities i've got
-sand grain size ?
-sand depth ?
-how long it's been running (how long before it failed) ?
-any spikes in ammonia/nitrate/nitrite ?
-(for those that failed) guesses, observations, symptoms, smells going on when it failed, even those that don't seem relevant ?
-any critters in the substrate (if present/used) ?

---

everything i've encountered about why a deep sand bed should not be done are given the same argument: concerns about Hydrogen Sulfide.

i'm aware of how toxic this gas is in the aquarium. it's one concern. a concern that, as much as i can find, can be neutralized. a concern that has been brought up by people who do not talk about what they were using in their substrate (above questions)


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## Michael

I have merged your two deep sand bed threads, and placed both in "substrates".


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## Flear

i've learned a lot since i started this inquiry.

how do you tell if a DSB in a planted tank is doing what a DSB is supposed to be doing, or if it's your plants ?


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## Flear

i have been unable to find a single example on the net of anyone who set up a freshwater DSB without plants.which sounds like the only use of a DSB (fresh or salt)

plants, to keep their roots healthy pump O2 down into the substrate.
at this point plant roots are reducing your anoxic substrate.
normal denitrification requires this anoxic zone for it's lack of O2

considering your DSB is being turned into 4"-6" or more of hypoxic O2 rich sand, ... and plant roots (and plants in general) suck back nitrates.

how do you tell if it's the DSB reducing your nitrates or if it's the plants that are reducing your nitrates ?


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## Bardus71

A good point Flear. I haver been pondering root depth myself tonight before stumbling onto this thread. Alot of groundcover plants may only have a root length of 1", but crypts and others may grow several inches deep. 

Measurement of a tanks effectiveness is another issue all together. I was thinking of doing a 4" DSB next to a 6" DSB and trying to compare them, but to do so without a comprehensive electronic test kit would be too labor intensive in my view. Imagine 2-3x comprehensive manual testing per day for 12 months. No thanks. The seneye kits are able to test ammonia, and pH etc, but not nitrates. I'm sure there are similar brands etc, but until there is a cheap enough electronic way to measure water parameters comprehensively, it will be left to old school testing & observation. I have 2x 18" tall 2'ers ready to go soon. Keen to try it all out.


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## Flear

i've never actually thought to consider root depth, i've just thought they grow towards the nutrients.

what i've heard of malaysian trumpet snails, they generally don't burrow more than an inch or so down. same for blackworms, ... except, one lady on another forum found blackworms at much greater depths wrapped around the roots of her plants (higher O2 by the roots)

a lot of what i've come across about DSBs are focused on the depth, or the side-effects of having them, and how to abuse them, few anywhere seem to talk about what they actually do.


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## Flear

before i put the idea aside i was thinking of testing them by seeing how many fish could fit in the tank before i noticed any rise in nitrates. the more fish it can handle the more success it proves in keeping nitrates at acceptable levels.

Edit:
long, expensive tests 

the cost of sand sieves to get an idea what grain size is optimal (again useing fish quantities to test)
observing depths to tell how deep the sand bed gets before anoxic environments start for the different grain sizes
trying to identify how far down the sand bed gets before H2S is forming.

other things i had come across.
as the sand bed fills with detritus all the numbers start to change.
some say the hypoxic sand grows, some say it gets smaller till the whole thing is anoxic, ... thanks internet for proving your unreliable.

grain shape, ... that makes the whole thing very expensive.
silica sand is very angular, it's cheap, pool filter sand, this is it. - like square/cube crystals, crystals are known for having significant edges.
then i was looking into sand blasting and foundry casting materials.
sand blasting glass beads, ... sand size, and near perfectly smooth and round.
where i live, it roughly turns into $1/lb in 40lb bags, but gentle on even the most sensitive fish due to it's shape and a high waterpore space to allow for things in the water to move easier between the different layers of sand. and it's never going to pack down because it's round.
if your looking for aragonite, for it's calcium PH buffer, there's oolite, also near perfectly round

looking into these perfectionist ideas was getting to be expensive.
i only stopped persuing the idea of a DSB when i saw it getting redundant, if the plants are going to suck back nitrates to the point i no longer need water changes, why add a DSB in addition to the plants when it's just going to take away from space/depth from the water column.

but the other ideas i had come across i held onto, sand shape & size.
they avoid silica in sandblasting and are cautious about it in foundry casting because it's known to be related to people developing lung cancers, ... and this is what we put in our fish tanks,


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## thefishguy

Too deep of sand bed causes anerobic(?..the no oxygen one) to grow causing stinky sulfide bubbles. This can sometimes is coupled with higher phosphates as well. U can get a larger algae explosion. 

Plants (generally) have roots as deep as the plant is tall. 2-4 inches is fine but I would aim for 3. Anything for than that can give problems. Also a undergravel heating cable creates micro circulation aidding in root nutrient uptake and growth.

ent from my BlackBerry 9800 using Tapatalk


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## Flear

H2S is only a worry if your stirring up your sand bed, ... then i'll say whatever the results are, whatever casualties you have are your fault, ... there is no reason to mess with a DSB unless your trying to wreck it.

a DSB works by being left alone

yes a DSB can cause H2S, and if you leave it alone then there are no concerns

yes, H2S is caused in the anoxic/anerobic substrate, that's also where the denitrification occurs.

stirring your DSB up does lots of things, ... it releases any H2S bubbles, it kills your anerobic/anoxic bacteria, it kills your aerobic/hypoxic bacteria.

so now you know if your messing with a DSB your intentionally & maliciously trying to kill your tank.

any questions ?

Edit:
apparently having a strong light in the area of H2S production will also product bacteria that consume the H2S that is produced. ... so put a light under your tank if your paranoid or cannot leave well enough alone and some screwed OCD complex insists you have to keep messing with things till they break. don't blame other people because you are killing things in your tank.


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## jseyfert3

Flear said:


> they avoid silica in sandblasting and are cautious about it in foundry casting because it's known to be related to people developing lung cancers, ... and this is what we put in our fish tanks,


I believe there is a difference between what causes lung cancer in humans and what harms fish in water. After all, fish don't have lungs.


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## Flear

materials that are sharp that your body has a difficult time removing will cause constant abrasions, ... this could be your lungs, this could be a fishes gills.


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## jseyfert3

Flear said:


> materials that are sharp that your body has a difficult time removing will cause constant abrasions, ... this could be your lungs, this could be a fishes gills.


But gills are not lungs. I'm not sure of the structure of a gill, but wouldn't the proximity to water keep things from sticking on a much larger bases then our lungs?


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## Flear

maybe it's overkill, maybe it's not a big issue, ... maybe business's figure your buying it so they don't care, it's cheap and you buy more. ... who knows, ... your choice.

yes, these business's want us coming back because we trust them.
how long does it take cancer to form in people from these carcinogens, ... 3 years, 5 years ?, 10 years ?, how long do your fish life ? maybe it's an issue, maybe your fish won't live long enough to tell you.

so it's overkill for me. it's a mild concern, but that one extra step.


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## Jnad

Hello!

I am very interested in the DSB theory after reading this article, and i have a 10G running with DSB to test it out.
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/dsb.html

Jnad


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## Flear

if your adding plants, (preferable), the roots will add O2 to the substrate and no anoxic zone will develop, or it will become undone, and no denitrification will be achieved. and plants will process nitrates as well, ... so same end result


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## Jnad

Yes i see what you mean, plants do the filtration in our planted tanks so there is no need for a DSB. That is probably correct, and also probably the reason there is very few using the DSB and the reason for very little information on the subjeckt on thebinternet.

I am not saying the DSB is a good thing, and i have no experience with DSB but i am somewhat interested in the subjeckt and did manage to find something, could it be that DSB have some other benefits other than filtration?

http://www.farmertodd.com/Freshwater/rainbowfish/default2.asp

http://www.farmertodd.com/pdfs/native_fish_tank.pdf

Jnad


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