Fresh water Deep Sand Bed

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countryboy

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Jul 20, 2012
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There has been some discussion about deep sand beds in fresh water aquariums. I have read about them in salt water using live sand. Neither have I seen them or known anyone to have a functioning DSB in fresh water aquarium. I admit to having limited knowledge in this area. It seems that if you could have a functioning dbs in fw aquariums there would be no need for any type of filter. Except for the occasional water change. Thoughts?
 

mesto

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Apr 28, 2012
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I have one. First off, MAJOR disclaimer in that I am a newbie and this is my first tank I've ever been serious about (had them as a kid in the 80s). So I totally get that time will tell. It has been set up for 4 months. I mixed several handfuls of rinsed potting soil mud into each lb of sand, too, and then capped with a thin layer of just sand.

Essentially, after I was done cycling, I have not seen any blips in the params at all. I've had two filters fail, and moved seeded filters to other tanks while leaving the "young" filter on the DSB tank with no result. I do test liquid test kits. I just added some new fish so I have been much better about water changes lately (30%-40% every week), but last month I went on several trips and was just really busy and let maintenance slip - 20% or so WC twice that month. Aside from the plants growing out of control, no issues.

I don't know how stable the tank would be anyway, I'm interested to compare the other tank I set up with ecocomplete so I can tease out what is from heavy planting vs. the sand bed itself. I wouldn't go totally filterless on my 40B otherwise mainly for gas exchange and mechanical filtration. I'm pretty sure the bed has way more heterotrophic bacteria than typical substrate and those just use a lot of oxygen. Maybe if you stocked it lighter than i have.

So far it sure doesn't hurt and might help. It looks nice too, and my fish seem to like it a lot. Plant roots go the whole 4" down and it just makes sense to me on a basic level. I study wetlands and I know the type with a deep muddy sand bed. Sure the bottom stinks of H2S2 if you dig it up - it means there's anaerobic bacteria down there and reducing conditions which the plants love. So I don't dig it up. Actually I do plant and move plants around no problem, and have never actually smelled any bad smells from my tank, but I do assume if I took a stick and really stirred it up it would stink...like a submerged wetland soil does. It makes sense to me but I think it's probably a personal choice that goes to aquarium style as much as special filter function.
 

Uaru

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Jul 31, 2012
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I know pretty much nothing about saltwater, but I have lots of sand in my 180g. I have to stir up the sand quite often where there's organic material or else it turns black as night with bacteria. I feel the need to keep it aerated and get that bacteria out of there. At least, keep from any gasses becoming trapped; those have the worst stench ever.

So would it work? I don't know... but I sure wouldn't want one!! If a fish were to stir it up... phew... I know with my first time discovering the bacteria, my whole room smelled for hours. I'm not so sure if it would be healthy for the fish anyway.

Mesto, how deep is that sand bed of yours? I know that as keeping a NPT. I have many NPTs myself with absolutely no filtration running. However, I give the plants credit for filtering the water. I just have a layer of dirt with a thin layer of gravel in mine with clear and clean water.
 

countryboy

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So would dsb's work with say Mbuna that like to dig. I think they have to be basicaly undisturbed don't they?
Are dsb's better suited for new world cichlids? How heavy of a bio load can you have?
 

mesto

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Apr 28, 2012
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My bed is about 4" at the deep side, 2-2.5 on the shallower side. I DO let it get the black anaerobic stuff - that's the whole point. It doesn't smell as of yet, even when I plant a stem and some bubbles come up. In fact there was more tank smell when it was new and as it's aged there is less and less smell and what's there smells like any fish tank to me. But I do wetland delineations with soil pits, and I am 100% certain if I scooped huge handfuls of sand up and stirred the whole thing at this point it would smell like rotten eggs, and possibly hurt the livestock. It's what we call a "double dipper" in wetland delineation in that the H2S2 smell serves as a legal indicator of both wetland soils and active wetland hydrology under the Clean Water Act.

I don't know about Mbuna, but I could be willing to try with shellies, honestly. It might make a good mini-model for Mbunas. My cories and MTS move the surface a lot and it seems to help work the mulm in so that's a benefit of disturbing the surface. People say you need plant roots to keep the substrate from getting too toxic, but since it's all reduced and anaerobic all around the roots outside of the 2 mm around each rootlet, I honestly don't know how much that is actually true and how much is speculation. Anyway like I said my bioload is apparently too big to go completely filterless IMO - I have a stock at 70% per aqadvisor. Current stock for my 40B is in my sig plus 3 platies. Not sure how big of a bioload you could go completely filterless with.
 

garyfla

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Apr 23, 2010
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Hi
You might google "plenum systems". There are a gazillion ways to go about the setup. Personally i don't like them for either FW or SW . The "best " IMo was the so called "false bottom " which is really more of a RFUGF but could easily be modified What I particularly liked about it was the ability to not only see what's going on but the ability to remove ths mulm. Think it would be great fo rifties or any kind of large diggers . Good luck gary
 

SubRosa

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Jul 3, 2009
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So would dsb's work with say Mbuna that like to dig. I think they have to be basicaly undisturbed don't they?
Are dsb's better suited for new world cichlids? How heavy of a bio load can you have?
Easiest way to incorporate one with diggers is to use a remote sump that incorporates a refugium. Given all of the pluses and minuses I'd personally put the time and effort into making water changes easier or even automatic. There is no replacement for replacement.
 

countryboy

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Throwing some black worms in. Planting and letting ditrius rot and clutter the substrate. Then adding external filtration and doing water changes. I wouldn't say that was a functioning dbs.
 

AbbeysDad

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Throwing some black worms in. Planting and letting ditrius rot and clutter the substrate. Then adding external filtration and doing water changes. I wouldn't say that was a functioning dbs.
Put very simply, even without plants, snails and worms, think of the deep sand bed as a huge bio-filter.
Many have come to believe that beneficial bacteria only lives in the filter. In fact, in the established aquarium, there is far more biology in the substrate. Deep sand just extends the platform to also accommodate anaerobic bacteria in it's deeper layers. The key is to NOT disturb the sand or disturb as little as possible.

Deep sand, like any other bio-filter, does not eliminate a need for some mechanical filtration, water circulation, and water changes. HOWEVER, leveraging [more] biology allows us to have a healthier tank with less filtration and lower volume (or less frequent) water changes.

Taking it to the next level, deep sand, living plants, MTS/worms, etc. leads us to a nearly self sustaining biotope. Consider...

Aquabella.com
Aquaripure.com

They tell us that with only modest mechanical filtration and the right bio-filtration, we can dramatically limit water changes while maintaining healthy tanks with crystal clear water.
Oh you can run canisters + hobs and change out 50% of the water weekly - that's one way....but just maybe it's not the only way and may not be the best way.
 
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