Logo
Please visit our Sponsors

FAQs on Freshwater Deep Sand Beds

Related Articles: Freshwater Substrates, Nice bottoms; Choosing the right substrate for your aquarium by Neale Monks, Freshwater Deep Sand Beds Work by Deirdre Kylie, Setting up a Freshwater Aquarium, Tips for Beginners

Related FAQs: Freshwater Substrates 1, FW Substrates 2,
FAQs on: FW Substrate Selection, FW Substrate Physical Properties, FW Substrate Chemical Properties, FW Substrate Amounts & Placement, FW Substrate Changing, Moving, Adding To, FW Substrate Cleaning, FW Substrate Issues,
FW DSBs,

 

Landscaping Fabric      8/6/15
I have some vague ideas of using polypropylene landscaping fabric (also called weed barrier) to control gravel movement above an UGF.
<Yes; this; and screen door material and more have been used for this purpose... and to make barriers for plenums>
It's fine enough that it could perhaps even keep sand in its place, and yet it passes water easily. I suppose the fabric would also become a bed for bacteria.
<A bit>
As long is it's just polypropylene without added chemicals, it should be safe for my tank, right?
<Yes>
Is there some obvious difficulty that I'm oblivious to?
<None really.... easy to cut w/ a utility knife or good scissors. Bob Fenner>
Re: Landscaping Fabric      8/6/15

Thank you.
I've enjoyed learning from WWM. Not only because it tells me things I don't know, but because of how I'm told:
Facts are generally substantiated, opinions are generally given as opinions, and new information seems welcome and accepted.
A rare treasure, in my experience.
<Ahh. BobF>

FW DSB - Egg smell and black plant roots 2/7/11
Hi!
<Mr. T, Stu>
I hope you don't mind me troubling you with this,
<Not at all>
I have been trying to loosely replicate Deirdre Kylie' forum post's on a FW DSB, I have around 3" of sand, various plants, some CB worms and Corys, a thin layer of mulm (I try to keep it to a minimum to avoid carapace burn on my crays, maybe overly paranoid).
<Mmm, I do think a minim of mulm is a good idea as well>
The tank has been like this since September 2010, and everything 'appeared' to be well until the tank started to stink of eggs, I figured this was part of the process and not to be worried.
I lost a lot of plants recently from the crayfish eating faster than the plants could repair, so I bought various grasses thinking no more of it, anyhow I noticed that they are not growing well at all. I pulled some clusters of grass out and found that the roots where all brown/black indicating a lack of oxygen (if the same applies to aquatic plants?). The rocks surrounding the grass to keep it in place are also black on the bottoms.
I guess this is an indicator that I have no aerobic region in the sand bed?
(I doubt it is dye from the black sand, as it is a decent brand)
<Yes>
It worries me as I am now unsure of a few things, my sand (Tahitian moon sand) is graded 0.1-0.3mm and I suspect that it may be compacting, or maybe the rock shelters for the crays are the cause?
<A contributor for sure... as well as not being very calcareous>
All else I can think of is that the worms are getting eaten faster than they are reproducing, the sandbed is not deep enough, or the crays are disturbing the bed too much.
<I think it may well be just the organic component sans circulation/oxygen>
I only have a very loose grip on how these things work and am fairly new to the hobby, I really don't want to risk gassing the inhabitants, and the smell is getting tiring even with carbon.
Thanks,
Stu
<It is time to consider, and act on taking this system apart, rinsing out the substrate... and re-setting it up. Bob Fenner>
Re: FW DSB - Egg smell and black plant roots   2/7/11

Thanks for the timely response Bob!
<<Welcome T/S>>
> <Mr. T, Stu>
The novelty of the surname Tickle never ceases to amuse :)
<<Ah yes>>
> It worries me as I am now unsure of a few things, my sand (Tahitian moon
> sand) is graded 0.1-0.3mm and I suspect that it may be compacting, or maybe  the rock shelters for the crays are the cause?
> <A contributor for sure... as well as not being very calcareous>
I take it an aragonite or coral based substrate is best from this comment?
<<Depends on the plant/species of livestock employed, your wishes, other aspects of water quality, source of biominerals>>
I am unsure of whether this meets the needs but I have a canister filled with coral to buffer my soft acidic tap water,.
<<Ah, there you go>>
This is the first I have heard of a need for calcium in a FW DSB (not that I am a whizz kid by any means).
<<Not the calcium really, but the carbonate, bicarbonate>>
> All else I can think of is that the worms are getting eaten faster than
> they are reproducing, the sandbed is not deep enough, or the crays are
> disturbing the bed too much.
> <I think it may well be just the organic component sans
> circulation/oxygen>
Does this mean the sand has got to be swapped and/or the depth reduced? Or are there other means to increase circulation in the substrate?
<<Just the organics rinsed out, removed. I would not be concerned w/ the matter of circulation therein... and would supply carbon, other nutrients exogenously... i.e. through supplementing... weekly likely>>
> <It is time to consider, and act on taking this system apart, rinsing out
> the substrate... and re-setting it up. Bob Fenner>
If the DSB has got to go then by all means it will go, I guess the crays will have to learn not to dig!
Full rebuild is pending your instruction :)
'crayfish day care' tanks are fired up and at the ready for some visitors!
<<Ah good>>
Thanks again!
<<Welcome! BobF>>

Cycling a FW DSB in an established tank - about 2 months, so far so good   11/22/10
I still have all the same equipment, but I have not been doing maintenance.
CO2 shows low, but plants are doing great.
<Cool. Proof of the pudding!>
Nitrate, nitrite etc are non existent. Water is clear, beautiful. I will start taking equipment out soon. I did try the Malaysian trumpet snails. I thought they were all gone right away (clown loaches) but just found two
fresh shells about a month after adding them to the tank.
<Yikes! I'd have though Clown Loaches a bit big for a tank with a DSB; surely they burrow into the sand? They'll certainly eat the worms and snails.>
I am still looking for some type of sand living organisms. I don't like the idea of adding California blackworms since they would need to be cultured outside of the tank and cannot actually survive in the tank for long.
<Really?>
I don't like the idea of Tubifex based on Bob's concerns.
<Agreed.>
Snails are not the best idea for my tank because of the clown loaches. I just found a website with all sorts of FW inverts. Particularly they have nematodes and FW copepods? They have a link to a site about culturing nematodes for fry feed and they say that they live in the sand, but they don't discuss the impact they would have on a FW DSB or if they would survive/reproduce. I have never heard of FW copepods and am skeptical. Any thought on this site, the products offered.
http://www.aquaculturestore.com/fwinverts.html#mworms
<Freshwater copepods are numerous, but they're interstitial organisms rather than burrowers. So all they do is "swim" among the tiny spaces between sand grains. As for nematodes, these can't burrow in any meaningful sense. Again, they slide between grains. So neither are a substitute for oligochaete worms or snails. Cheers, Neale.>

Cycling a FW DSB in an established tank -- 10/11/10
I have decided to start a deep sand bed based on Neale's suggestion to my question about gravel vacuuming on 9/27/10. I am basing it on the Deirdre Kylie article. I took out my gravel and put 3 to 4 inches of silica sand in the tank (I have a cheap/free source) about 10 days ago. It looks beautiful, hopefully I still like it when the mulm starts building.
Until the bacteria build up in the sand bed, I figured I should keep my old filtering system.
<Yes>
But, from the description in the article, running the equipment will keep the biological filtration in the sand from developing,
<It/this will not>
so how do I keep the tank healthy until the sand bed develops. I have a pretty high bio load.
<Leave other filter/s going. Don't change out the filter media>
It is a 45 gallon tank with a whisper 40 filter and a Duetto 20. I have a diy CO2 pumped into the air intake in the Duetto. I have a whisper 20 air pump with one airstone. Based on my equipment and the article, I plan to take all but the Duetto out.
<In a month or so>
The other problem is that I let the yeast in the diy CO2 generator run out of sugar then took out the air stone. The following morning, one of my rubber lip Plecos (4 inch max variety) was dead and my catfish (not Pleco type, 5 inches full grown and my oldest fish) was gasping. I immediately put the air stone back in. My CO2 is pretty much non existent now. I am not sure what to do to wean the system to the DSB. Any suggestions would be greatly appreciated.
<Time going by... experimenting by turning off the outside power filter for a day or so at a time about a month from now>
Also, in reading the FW DSB FAQ I noted that Bob discouraged the use of California blackworms, but Neale encouraged and the article encourages. I am wondering why Bob does not like them?
<I do "like" Blackworms... not the (often) sewage-fed Tubifex>
Thank you,
-Astrid
<Welcome! Bob Fenner>

Re: Cycling a FW DSB in an established tank  10/15/10

K, as usual, the answer (along with an attempt to purchase) elicits even more questions.
I have ordered 20 Malaysian trumpet snails. I have looked into assassin snails to limit the MTS, but I have 2 clown loach (I hope some MTS can survive to aerate).
<Your clowns will likely consume these snails>
I have been google'ing "California blackworms." (and spoke with a breeder)
I have found that they need to be stored in cold water (fridge). I have also found that Tubifex worms can be kept in warm water. It seems to me that the blackworms would be more likely to die and foul the aquarium, while the Tubifex worms would live in and reproduce in the sand bed. I also found that Tubifex worms cause a type of food poisoning or disease (cant remember the specifics). I have gouramis, knife fish and leaf fish, as well as cleaning crew (loach's, small Plecos and Otos); Are blackworms really the best option for my planted DSB?
<No worms are actually better than trying to stock either of these annelids. Like marine systems, some purposeful interstitial fauna might be intentionally introduced in freshwater DSBs... there is likely a coming market for producing and selling such a mix, ala the beneficial bacteria business currently>
Once again, thank you. You all are immeasurably generous (to put up with all of our idiotic questions.)
<Not idiotic at all... BobF>
Re: Cycling a FW DSB in an established tank   10/16/10

Are blackworms really the best option for my planted DSB?
> <No worms are actually better than trying to stock either of these annelids.
<<Huh? Worms vs. annelids. I am afraid, I don't get it.>>
<That is, no worms period>
Like marine systems, some purposeful interstitial fauna might be intentionally introduced in freshwater DSBs... >
<<Yes, I am trying to determine what the best fauna is.>>
<Microbial... and incidental... i.e., what might come in w/ plants, foods... As far as I'm aware there aren't mixes of DSB critters being cultured, sold for freshwater use (there are for marine)>
> Once again, thank you. You all are immeasurably generous (to put up with all of our idiotic questions.)
> <Not idiotic at all... BobF>
<<K, incessant.>>
-Astrid
<B, unrelenting>

Deep substrate to lower nitrates in sump.    8/7/10
Hello,


<Hi Richard,>
I have a 75 gal tank with a Firemouth, Convict, and 5 Tilapia. I have an Aqueon model 3 sump configured with a refugium and a 980Gph pump which returns to an under-gravel jet system covered by 3" of crushed coral. I simply cannot keep up with my nitrates. Weekly water changes still leave nitrates over what test kits can measure. After reading your DSB articles, I was thinking that such a thing just might be a solution beyond building a nitrate reactor.


<It is one option.>
The problem is that I'd have to completely re-build my UG Jet system to accommodate 5"+ of substrate (the jets would be under the substrate). This would require tearing down the tank (it's siliconed to the bottom), and I don't have the facilities do house the fish should I attempt this.


<Probably not the best solution then.>
Do you think that putting 5 or 8 inches of crushed coral or sand in the refugium would work in my case instead? Or is this too little to have an effect?


<Is the refugium in the 3rd chamber of the Aqueon 3?>
Right now I have some plants and moss balls in the refugium, but no substrate.


<While a deep sand bed is an option, it isn't always the best solution. Some people have great results with them, others no results at all. A plant filter which uses natural sunlight, or a few hundred watts of HID lighting is my recommendation. Plants eat nitrates. It is the perfect symbiosis.>
Thank you, Richard


<Hope this helps, Scott T.>

Re: Deep substrate to lower nitrates in sump. FW   8/8/10

Thank you for the quick and helpful reply.
The refugium is the 2nd and largest of the three chambers, in the middle.
It has 11 inches of water depth and has T5 lighting fixture designed for it. That is no where near a few hundred watts of HID though (might melt the clear cover).
Can you recommend a replacement fixture and plants that are voracious nitrate eaters? The flow rate in the refugium is enough to keep moss balls juggling around gently, so that is probably a factor.
<Maybe the best approach is three tiered. Try a deep sand bed, fast growing plants, and make sure to remove as much particulate waste as possible.
Is this the sand bed article you referred to?
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/dsb.html
I would follow it's directions for installation of a sand bed in your refugium. Then put some plants in that are fast growing. Lemna minor, Limnobium laevigatum, and Hygrophila are a few. Or any fast growing plants you have access too or success with. To light these a DIY 150watt HPS would work. Or something like a Current SunPod model 1058. It is a somewhat small area, so the plants alone will not be able to keep up with the nitrates themselves. The combination of a DSB, plant filter, and well used filter bags should do the trick.
My favorite option for filtering large freshwater bio-loads is Aquaponics. If you are inclined, it is a wonderful symbiosis.
http://en.wikipedia.org/wiki/Aquaponics >
Thanks again for the input.
<Thanks for contacting us. Keep the questions coming.>
-rr
<Scott T.>
Re: Deep substrate to lower nitrates in sump.  8/8/10
Hello Scott,
Actually, this entire setup is for Aquaponics!
<Too funny, go Aquaponics!>
I just haven't started the grow beds in the grow tent (secret Jardin with a 1000w HPS, reflector, blower, etc) because the waste heat is too much for my air conditioning. I live in an apartment in Manhattan. I was sorely
disappointed when I fired everything up once I had it built.
<Darn summer heat. I had to shut down my indoor setup for the same reason.>
I have three aeroponic style beds plumbed to the return pump of my aquarium sitting in the dark grow tent waiting for the fall. I will be growing tomatoes and salad greens. I am not sure if I'll harvest the Tilapia though I have kept them on a certified organic feed that aquaculturists use.
<I did a similar thing with Koi.>
Anyways, thanks for the input. Especially the plant names and the link.
<I'm not certain, but I bet tilapia can deal with high nitrates. My nitrates were always a bit elevated with the Koi-aquaponic system. As long as you keep the pH reasonable with water changes, and ammonia is minimal, you should be all set. What are your water changes like? I did ~30 gallons a week on a 120 gallon system. The nitrates were always crazy, but the fish and plants grew like crazy too. For me less than 25% a week, and the fish suffered. It is also highly dependent on feeding. When not growing vegetables, reduce your feeding rate. If I fed the Koi as much as they wanted to eat, I would have had to do 25% water changes every day to keep things in check.>
-rr
<Scott T.>

DSB Questions, FW, Af. cichlid systems  7/20/10
Greetings crew,
<Hi Paul,>
I just set up my latest 55gal tank with sand and I have a few questions.
The sand I bought is white and really fine, it looks like its going to be fairly compact so I was thinking about putting some live plants to help break up the bottom.
<Can help, but with cichlids this often isn't viable. By all means try something robust like Vallisneria and see how things go.>
I read the FAQ's regarding DSB's so I put about 1 1/2"- 2" worth of sand.
Should I have bought some gravel to mix I with it or perhaps a bag of crushed coral?
<You can do this, but a lime-rich substrate isn't going to be welcomed by most plants, though Vallisneria and Elodea-type things won't mind. In my tanks I use a mix of fine gravel and smooth silica sand in varying ratios
to create attractive substrates. I prefer to leave the water hardening components to Rift Valley salt mixes and/or bags of crushed coral placed inside the filter. Do read here for a recipe:
http://www.wetwebmedia.com/fwsubwebindex/fwh2oquality.htm
Sticking lime in a substrate without an undergravel filter will have a low and unpredictable buffering effect.>
Having sand that fine isn't going to cause any harmful side effects to the fish will it?
<Depends on the sand. Do check with the manufacturer; some fine sands, e.g., Tahitian Moon Sand, are abrasive and can irritate the gills of digging fish. But in itself, no, fine sand isn't particularly hazardous.>
As far as stock goes I would like to put Labidochromis caeruleus and Haplochromis sp. 44 but I'm wondering if they will cross breed?
<Nope. One's a Malawian and the other a Victorian, so they do have somewhat different water chemistry requirements.
http://www.wetwebmedia.com/ca/volume_5/volume_5_2/malawian_cichlids.htm
http://www.wetwebmedia.com/ca/volume_6/volume_6_3/vic_chichlids.html
In terms of temperament they should be okay together in a big enough tank, though I fear 55 gallons is pushing your luck; 75-100 gallons would be
better.>
Thanks
Paul
<Cheers, Neale.> 

Re: DSB Questions, FW, Af. Cichlid stkg./sys.   7/21/10
Neale,
<Paul,>
Thanks for the links, they were very informative. I didn't know that Lake Victorian cichlids were that hard to come by.
<Does depend, with one or two species being widely sold but often inbred, while others are hardly seen outside of cichlid clubs.>
I'm going to skip the coral idea per your input
<Wise. While adding a little coral sand isn't a bad idea if you're not growing plants, it doesn't guarantee hard water conditions, so it's a "why bother" sort of thing in many cases. Much better to either add something to the water, or else place a bag of crushed coral in the filter you can clean under a hot tap regularly.>
I do have a question concerning cycling it though. The sand made the water fairly cloudy so I did a straight water change water conditioner, and I'm going to do another water change tonight.
<Fine.>
I was planning on using water from my 72 bow so I tested the water and I found out that it was still showing nitrates at 10-15 ppm. nitrites and chlorine at zero.
<All sounds good.>
So I did a 30-40% water change and watched it for a few days and tested it again last night and the nitrates were back to what they were.
<Yes.>
I also noticed one of my red empresses were flashing against the bottom occasionally.
<Unlikely because of the nitrate. 10-15 mg/l is a good level for cichlid aquaria.>
For stock I have 3 3 1/2" Red Empress and 7 2" Frontosas.
<An interesting combo. Should work, though both are big fish, and space may be a problem in the long term.>
I have been feeding them once a day light feedings and the tank has been running for close to 3 months (I'm using 2 Penguin 350 filters). Should I not use this water to start cycling and just use fresh water and add flakes to start the cycle?
<Oh no, I wouldn't do this. I'd "clone" the filter if at all possible. All biological filters can lose up to 50% of their biological media without a dramatic drop in filtration capacity. So if you have ceramic noodles, scoop out half from the established tank's filter, put them into the filter in the new aquarium, and then transfer some fish across to the new tank to supply ammonia. Should work fine. Moderate the food a bit for the first week, maybe to half rations, but otherwise shouldn't be any noticeable rise in ammonia and nitrite. Given you have two biological filters, moving one filter to the new tank, plus half of the fish, should work too. But that assumes water turnover stays acceptable in terms of oxygenation and distribution of heat, so be careful there. If the Penguin 350 is supposedly able to handle either tank by itself, this should be safe. Otherwise not, and you'd want to replace the missing filter on the donor tank with another filter. Water itself contains little/no useful bacteria so moving it around is pretty pointless. Moving gravel can work if there's an undergravel filter, but otherwise again, it's fairly pointless except for the top half-inch or so of gravel which should contain some bacteria.>
Regards
Paul
<Cheers, Neale.>

Questions on Freshwater Deep Sand Beds   3/17/10
Hello!
<Hi there>
I must commend all of you for keeping up such a wonderful and helpful site.
I greatly enjoyed the most recent Conscientious Aquarist Magazine. Ever since reading one of the FAQ a while ago where an upcoming article on freshwater deep sand beds was mentioned, I've been eagerly awaiting its release! What a helpful article! (I will certainly start leaving roots behind when I move/rescape plants.)
Of course, like all good information, it leads to so many more questions!
My system is a well-established 135gal densely planted discus & community tank running on a 75gal sump, with pressurized CO2, high light, and substrate heating cables. I have a couple questions about using a DSB on this system. The substrate, currently, is about .75' of mineralized soil capped with about one cm of Oil Dry (identical to Fluorite, but more economical) and 1-3' of pool filter sand on top, depending on location in the tank. Do you think I could turn this substrate into a DSB (rather, would it be worth it, when the system works well as is?).
<I think that all sand beds function in part as DSBs, with deeper ones, of smaller/finer, rounder, more chemically propitious ones operating better>
While I don't think that the soil would cause a problem if I were to start using the substrate as a DSB, would the Oil Dry?
<I don't think it would>
It has 'large' pebbles, just like Fluorite. Also, substrate heating cables allegedly move oxygen through the substrate; would these cables, by doing their job, just make developing a DSB impossible?
<Some partial (not anoxia, by hypoxia) oxygen through induced heat/convection (along with Brownian Motion et al.) is valuable>
The only other 'real' sand disturbers in the tank are the sterbai cories, Malaysian Trumpet Snails and their Assassin counterparts (to be fair, I have to grow the MTS in the sump and periodically move them, as the Assassin gang wipes them out faster than I can add them).
<Both neat animals... that do a bunch of burrowing as you know>
I already had Blackworms on the way, intended for use as discus treats. If I add them to the tank on the substrate, they will be found and eaten quickly -- can these be buried without killing them?
<They will/do find their way into some depth, low oxygen settings>
Or would I be better to add them to the tank at night, in the thickest bits of plants? What will the bioload of the worms do to the balance in my tank?
<I would not add these on purpose myself. These worms live in conditions that you really don't want to replicate for your other livestock. If some live, so be it>
The tank is densely planted now, such that even with 900+ gph turnover from the sump plus a *Koralia 2 powerhead, mulm still settles on the substrate (beneath the plants). If I understand the article correctly, I should leave this mulm? It seems to sit on the substrate rather than move into it.*
<Some is okay... depending on the type of livestock you keep... I'd siphon some out for looks periodically, along with water change-outs>
My other alternative would be to add a DSB to the sump rather than the tank.
<Yes>
There *is* currently a 'freshwater 'fuge' area in the sump (I can hear the salties chuckling from here!) that I could add sand to. Would this perhaps work better than in the main tank?
<I like both sites for many types of FW set-ups... the remoted/sump/refugium is better for maintenance, manipulation obviously>
Or in addition to a DSB in the main tank?
<Up to you, or both>
Is there any benefit to making the sand bed deeper than the three inches laid out in Deirdre Kylie's article (3' seems shallow as is?)? (If so, by how much?)
<Mmm, yes... 4-6 inches isn't too much, again, depending on what you're growing, wanting to do... and of course the trade-offs you're making with losing the equivalent water volume>
Thank you so much for all you do, especially putting up with merciless picky questions like these!
Tianna
<The "devil" and heaven are "in the details". Keep that good mind of yours going Tianna... we/the world need it and you. Bob Fenner> 
Questions on Freshwater Deep Sand Beds, Neale's go    3/17/10
Hello!
<Hello,>
I must commend all of you for keeping up such a wonderful and helpful site. I greatly enjoyed the most recent Conscientious Aquarist Magazine. Ever since reading one of the FAQ a while ago where an upcoming article on freshwater deep sand beds was mentioned, I've been eagerly awaiting its release! What a helpful article! (I will certainly start leaving roots behind when I move/rescape plants.)
<It is an interesting piece.>
Of course, like all good information, it leads to so many more questions!
<Oh?>
My system is a well-established 135gal densely planted discus & community tank running on a 75gal sump, with pressurized CO2, high light, and substrate heating cables. I have a couple questions about using a DSB on this system. The substrate, currently, is about .75' of mineralized soil capped with about one cm of Oil Dry (identical to Fluorite, but more economical) and 1-3' of pool filter sand on top, depending on location in the tank. Do you think I could turn this substrate into a DSB (rather, would it be worth it, when the system works well as is?).
<There is a minimum depth referenced in that article. I can't remember off-hand the number, but if the substrate you have is LESS than that depth, no, it won't work as a DSB. Particle size will make a difference though; the finer the substrate, the better it works as a DSB. To a degree, you have to experiment a bit if you're going to depart from the recipe. For what it's worth, in my tanks I observe DSB-like activity once the substrate depth is around 10 cm or so (about 4 inches).>
While I don't think that the soil would cause a problem if I were to start using the substrate as a DSB, would the Oil Dry?
<I don't know. Never even heard of "Oil Dry".
It has 'large' pebbles, just like Fluorite.
<Pebbles are bad. You want a uniformly fine substrate. If you think about it, if a bed of sand works as a DSB, but a chunk of concrete of the same size doesn't, then anything less like sand and more like concrete will be less effective.>
Also, substrate heating cables allegedly move oxygen through the substrate; would these cables, by doing their job, just make developing a DSB impossible?
<Again, I don't know, but I doubt the convection currents created by a substrate heater would make a huge difference either way.>
The only other 'real' sand disturbers in the tank are the sterbai cories, Malaysian Trumpet Snails and their Assassin counterparts (to be fair, I have to grow the MTS in the sump and periodically move them, as the Assassin gang wipes them out faster than I can add them).
<Yes! aren't they fabulous little predators!>
I already had Blackworms on the way, intended for use as discus treats. If I add them to the tank on the substrate, they will be found and eaten quickly -- can these be buried without killing them?
<Possibly, but I wouldn't bank on it.>
Or would I be better to add them to the tank at night, in the thickest bits of plants?
<Could you use a yoghurt pot or something similar to "seal off" a portion of the substrate, put the worms underneath, and leave in place like that for the night? That should keep out the catfish.>
What will the bioload of the worms do to the balance in my tank?
<Hopefully not much overall. While they will add to the ammonia produce and will consume oxygen, by improving the DSB, they should improve water quality.>
The tank is densely planted now, such that even with 900+ gph turnover from the sump plus a *Koralia 2 powerhead, mulm still settles on the substrate (beneath the plants). If I understand the article correctly, I should leave this mulm? It seems to sit on the substrate rather than move into it.*
<Will do so initially, but like leaf litter on the soil, the bottom layers are slowly decaying into the substrate.>
My other alternative would be to add a DSB to the sump rather than the tank.
There *is* currently a 'freshwater 'fuge' area in the sump (I can hear the salties chuckling from here!) that I could add sand to. Would this perhaps work better than in the main tank?
<The bigger the DSB, the better, but a small one in a sump is certainly worthwhile, and much done in marine fishkeeping.>
Or in addition to a DSB in the main tank? Is there any benefit to making the sand bed deeper than the three inches laid out in Deirdre Kylie's article (3' seems shallow as is?)? (If so, by how much?)
<Up to a point, yes, a deeper DSB is good, but there's a balance between creating the DSB and wasting water capacity by filling the tank with sand. By all means add an inch or two and see how things work out, but I wouldn't go crazy.>
Thank you so much for all you do, especially putting up with merciless picky questions like these!
<Happy to help.>
Tianna
<Cheers, Neale.>
Re: Questions on Freshwater Deep Sand Beds -- 03/18/10

I am spoiled! Two great answers for one question! Thank you so much!
<Welcome>
A follow up question, if I may? I think I will start with a DSB in the sump, as should I not like it/something go wrong, it is much easier to remove without stressing the fish.
<Agreed>
If I like that, I will add more sand to the display. Would I count the mineralized soil towards a ~4" depth for the DSB, or just the sand?
<All counts>
It would seem that total depth would make sense, except for the concrete analogy - I am sure that over time the soil has compacted very much.
<And even "disappeared">
For interest's sake (and for all of the economical planties out there), Oil Dry is a product used in automotive and manufacturing industries, among others, to clean up oil. It (or at least some of it) is a pure clay product that is apparently "food grade" (although I can't fathom how/why you'd have food grade clay...and I probably don't want to know!). Because of the nature of the product, it is extremely inexpensive and can sometimes even be found free.
<http://www.oildri.com/>
Neale, I did try your great (and so simple!) re-purposed container idea - which did let the Blackworms into the substrate - but since the worms rest with their heads (tails?) skyward, the cories simply slurped them from the
sand like spaghetti. Based on Bob's recommendations, I won't try adding them again.
<Will share w/ him>
Thank you again for everything that you do for the hobby! (And thanks Bob for that great lecture at CAOAC last year!
<Ahh! A very nice time out in Ontario, Canada>
This tank was the lonely "yes" in a room primarily full of freshwater hobbyists when you asked who actually ran a sump.)
Thanks,
Tianna
<Thank you, BobF>

Sand beds in Freshwater tanks    2/16/08 Hi Bob, Amy here I have the Oscars with "HLLE" I have been writing you the last couple of days. So much information on this sight. It's really great. I haven't really seen that sand beds are that common for freshwater fish. <Mmm, no... for a few "reasons"... mainly just perceived as being too hard to maintain> I just yesterday cleaned all the rocks and sand in my upper aquarium 220 gal. I never told you I had a partial sand bed. I have very fine rocks and about 80 pounds of Moonlite sand total of about 4 inches deep. It seems to be enough sand to fill the gaps between my fine gravel. Maybe that's why I have those little white worms. I also see air bubbles in my rocks at times. That should be good. Maybe not now that I cleaned them, no more bubbles. My Aquarium has been set up for about 1.5 years now. I do clean my gravel bed in my upper tank, but not very often. Normally I just get the loose debris off the surface. The last couple of days, I really cleaned all my rocks because of my problem with "HLLE". Did I just remove all the good bacteria from my tank? <Mmm, assuredly not> The sand / gravel really wasn't that dirty, probably because it is so dense. I did not move my stationary rocks and caves to clean. They cover about half of my aquarium floor. So there should still be bacteria there. In the future how should I clean the sand / gravel in my upper tank? <... this is posted as well... Please learn to/use the indices and search tool on WWM> Is a sand bed beneficial to freshwater fish? <Can be if maintained adequately> When I set up I thought " more natural" is better, right. I know sand beds are great for saltwater and I may change over some day. I want to do the best for my fish. Thanks for all your advise. Amy <Please read here: http://wetwebmedia.com/FWSubWebIndex/fwsetupindex.htm the second tray, FW substrates, the linked files above...> Oh one more thing. I am going to feed my fish food with Metronidazole in it. I also think I'm going to start treating for fin rot today, with Pro Series Fungus Cure. Let me know if you think that might be a bad idea. When the fin rot treatment is completed I was going treat my water again with Metronidazole. <Please... read re on WWM. I would only treat once with Metronidazole...> Just so you know, I always remove the charcoal when I treat with medications. Thanks again for the help. I'm going to try feeding peas and crickets today. I hope they like it. Thanks again, Amy <Keep reading my young friend. BobF>

Freshwater deep sand bed experiments   7/2/07 Your website alludes to some experiments that were to be done about nitrate reduction using deep sand beds in a freshwater system. Any results available? <Mmm, w/o a "trip" to the/a large library here with access to computer bibliographic search... I can only state from vague memory (nothing in my hard files) that I have seen articles in other languages (German, French, and likely Italian and Japanese) re this phenomenon. There are discernible "effects", practical implications of DSBs, use in FW aquariums> There are a couple of problems I could see. The marine sand beds are dependent on sand sifters and burrowers it sounds like, <To a larger extent... the variability in the make up physically, chemically, biologically... of such disparate "habitats", marine, freshwater and otherwise is huge... Suffice it to state that many FW bodies have significant infaunal populations. I suggest perusing a limnology text...> to move material around and prevent excess stagnation and hydrogen sulfide production, according to some web site sources. Maybe no such organisms are available for freshwater systems. <Mmm, perhaps not yet... but like marine "live substrates" these can be made pretty easily...> Do the sand beds really work for freshwater? Particularly for a soft water (Amazon) tank.... <Mmmmm, interesting thoughts... IF one could receive a starter inoculum... or even just some "muck", what have you, from an importer of... plants from this region... Bob Fenner>

Freshwater deep sand bed  7/5/07 I was wondering if the "experiments" outlined below by Magnus (a previous WWM discussion) have had any results yet. The deep sand bed idea in freshwater seems questionable, partially because of the lack or less sand sifter organisms available. Some sources, including the freshwater substrate article on your WWM site, caution against anaerobic pockets causing poisonous by-products. <Greetings. I can't comment on Magnus' work, so I'll leave Bob to fill in there. But I do have some thoughts of my own. Freshwater aquarists are quite well served with sand-sifting organisms. At the top level you have fish: catfish, spiny eels, loaches, etc. that will continually sift or burrow through the top few cm of the substrate. Going a little deeper are things like Malayan livebearing snails. Oligochaetes like Tubifex could potentially work, but the problem is most fish would eat them. Finally, you have plant roots. Aquatic plants transport oxygen down their roots via special air channels. This allows the cells in the roots to survive even in the anaerobic mud where plants extract the minerals they need. So while it is potentially possible for anaerobic conditions to develop in a freshwater aquarium, in practise it is relatively uncommon. I've used relatively deep sand substrates (up to around 15 cm) in freshwater tanks on and off for 15 years, and never yet seen any signs of toxic anaerobic decay. This isn't to say it can't happen, but in a well-maintained planted aquarium it seems to be a low risk problem.> The Deep Sand bed does have the same ideas in freshwater as in SW, the dense area is devoid of O2 so the bacteria can set up home, and start working on the waste. And it seems having that and a nice mechanical filtration on a freshwater tank does seem to be as beneficial to the health of the tank as it does in the world of salt. In fact I'm dealing with a aquarist in PA who is currently trying to study the benefits of DSBs and other properties in the freshwater world. Hopefully we make some nice findings with our studies, and help the freshwater world.>=>(I have a pond in the garden that is heavily grown with algae and water lilies, and teaming with guppies and rams for almost a year already. The substrate is about 3 inches thick. Could this be considered a DSB?)<I really wouldn't consider it a DSB, I consider anything over 4-5 inches deep as sand beds go. In freshwater ponds, the sand is a great host for many insect larva, that act as the clean up crew in oceans... The only problem is that these larva grow up, and turn into large stinging/biting/scary looking adult flying insects, so we can't bring them into the home aquarium. Sounds like you have a healthy pond there! Good luck. -Magnus> <Your observation of the pond situation is important. In practically all freshwater habitats, anaerobic conditions exist below the surface of the substrate. In lakes, anaerobic waters exist below a certain depth because of the lack of water current. (In the sea, by contrast, water currents exist at deep levels because of the cold water flow from the Arctic and Antarctic, reaching as far as the equator.) Anyway, aquatic plants *depend* on the anaerobic conditions and cannot do well without them. Oxygen-rich mud converts mineral ions such as iron from the reduced to the oxidised state. Plants can't absorb the oxidised state. This is why plants have evolved that oxygen transportation system mentioned earlier. If you look at aquatic plants under a microscope, you will see they are very spongy, and its those holes that allow the oxygen to travel down to the roots. As is so often the case with plants, their solution to this problem is simple, elegant, and very efficient.> Versus these cautions elsewhere on your site: The use of deeper and or finer grades of substrate are used to anaerobically ("without oxygen") convert nitrates back to gaseous nitrogen for removal from the system. There are definite benefits and dangers in these approaches versus the use of live plants, water changes, and chemical filtrants'¦ to alleviate nitrate accumulation. The potential downsides of this anaerobiosis are production of noxious by-products like hydrogen sulfide gas (rotten egg smell), which can be deadly. <My gut feeling about nitrate removal in freshwater tanks is that attempting to use a DSB is probably not really worth the effort Admittedly, I haven't yet seen H2S develop in a freshwater tank. Furthermore, while I have seen gas bubbles in deep sand substrates, these seem to be harmless, so are presumably nitrogen or possible oxygen from the plant roots. But there are simply much better ways to remove nitrate in a freshwater tank. Water changes for one thing are so much cheaper and easier. If you have fish adapted to your local water chemistry (the ideal situation) then you can do water changes as often as you have time! Secondly, plants are fantastically efficient nitrate and phosphate removers. If you have fast growing species like Cabomba, you are cropping them back weekly, so effectively running a "vegetable filter". Finally, freshwater fish are largely nitrate tolerant. The oft-quoted but still instructed statistic is from lab work on trout, which are 1000 times more sensitive to ammonia and nitrite than they are to nitrate. For a standard community tank without nitrate-sensitive species nitrate level of 50 mg/l is fine, and even up to a 100 mg/l is unlikely to cause problems. In special cases, as with discus and mollies, you need lower levels, and Tanganyikan cichlids especially are very intolerant of nitrate. But Neons, Corydoras, angelfish, gouramis, etc. are indifferent to all but the highest levels of nitrate. This contrasts with the situation in marine fishkeeping where nitrate is more or less toxic to the species being kept. Even a fish-only system wants something less than 20 mg/l, and reef tanks practically no nitrate. The Zooxanthellae in the corals don't use up nitrate at anything like the rate of fast-growing plants, so coral growth isn't a significant nitrate dump. Hence the value of DSBs in marine tanks. Anyway, those are my thoughts. I'm sure Bob and others may have ideas as well. Cheers, Neale.> <<Scant few. RMF>>

Deep Sand Bed for Fresh water aquarium.   11/8/06 Hi Guys, <Oooh, what about the XXs?> I am new to this site but I used to keep marines - then I got married, had kids, got a proper job - pretty much in that order... <Let's see... in the not so wild west, "First comes... then comes familiarity...> Now I return, but have decided to keep Malawi Cichlids (Haps and Peacocks). <I keep these... and Mbuna in another system> I am still researching the species and bringing myself up to date with latest filtration techniques etc. I am space limited and so I know that the size of the tank is fixed at around 90G. I am interested in using a sump - for various reasons, but it has a lot to do with requiring a low maintenance, stable system because I am away from home 4 days a week. (That's what a proper job does to you). I am interested in incorporating a NNR refugium type compartment in the sump, and have read around the subject a little. However, I have a couple of really basic questions that I can't find answers for. This is why I write. My first question is how do they work? <Mmm, NNRs? Basically they harbour, foster anaerobic microbe populations... mild circulation delivers system water to the hypoxic bed, and chemical substrate (e.g. Nitrates) that are reduced (as in Reduction/Oxidation) to component molecules> Ha! Don't get upset. 6 inches of sand directly on the bottom of the tank with no forced water flow through it leaves me confused. How is the water that had nitrates removed replaced? How does water exchange work in the filter bed? <Is the same water... recirculated with/through the system en toto... and the water exchange is purposely very slow, gradual to keep oxygen tension low> My second question is this. If I set it up with a plenum, an uplift tube and a very low flow rate (say a few gallon per hour) will the efficiency of the sand bed be increased or destroyed? <This depends on still other factors/circumstances of how much substrate, its "grade", chemical/physical make-up... slow as you go is the route to go here... no uplift tubes, the "holes" for these plugged... No aided circulation through the bed other than simple diffusion, Brownian motion> (This is of course just a UGF with a low flow rate). When I was keeping marines the accepted wisdom at the time was that aerobic processes occurred in only the top inch and a half of substrate. Therefore it seems to me that with a deep sand filter some forced water movement could be acceptable without dragging oxygen too far into the bed. <Ah, yes... I remember those days/years> In any case it could be possible to increase the depth of the sand to compensate. <Yes, to some/an extent> I should add that the reason I am tempted to do this is again due to lack of space. The entire sump needs to be 80LX40WX40Dcm max. Any help you can offer would be very welcome. Thanks, Tony Baxter <The same rationale, design, operation... of such filtration, filters as per marine... Please use the search tool and/or indices on WWM to read about Plenums, DSBs for marine/SW set-ups... http://www.wetwebmedia.com/deepsandbeds.htm http://wetwebmedia.com/Plenums.htm and the linked files above... and apply this to your application. Bob Fenner>

Deep Sand Beds in a freshwater aquarium Hello! <Magnus at your service> I'm a saltwater aquarist who has recently been enlightened on the beauty of freshwater fish, especially dwarf cichlids. <Very fun and active fish!  definitely some of the more colorful and interesting fish to have.> Currently I have a mini-reef aquarium utilizing the live rock and DSB system that has been running for 6 months already, and I am planning to set up another aquarium - this time freshwater. DSBs are wonderful, as I see no need to vacuum the substrate for debris, and the biological filtration is performed altogether. <I agree completely, my reef tanks have DSBs and they are going amazingly well so far.> Could I use a DSB coupled with some form of mechanical filtration system in a freshwater setting if I were to keep rams (Microgeophagus ramirezi) only, or a DSB is only meant for saltwater aquariums? <The understanding of DSBs on Freshwater tanks is only now being studied.  after all the idea of a deep sand bed on reef tanks was only really "discovered" in the past 5-10 years.  I do know of many people quite happy with sandbeds in their cichlid tanks.  The best thing it seems to have on your freshwater tank if you have a deep sand bed is a clean up crew.  Containing snails (like apple snails, gold Inca snails, or mystery snails.)  Some people also have crayfish in their tank... though caution is needed cause crayfish will eat a fish if it can get it's claws on it.  The Deep Sand bed does have the same ideas in freshwater as in SW, the dense area is devoid of O2 so the bacteria can set up home, and start working on the waste.  And it seems having that and a nice mechanical filtration on a freshwater tank does seem to be as beneficial to the health of the tank as it does in the world of salt. In fact I'm dealing with a aquarist in PA who is currently trying to study the benefits of DSBs and other properties in the freshwater world.  Hopefully we make some nice findings with our studies, and help the freshwater world.> =>(I have a pond in the garden that is heavily grown with algae and water lilies, and teaming with guppies and rams for almost a year already. The substrate is about 3 inches thick. Could this be considered a DSB?) <I really wouldn't consider it a DSB, I consider anything over 4-5 inches deep as sand beds go.   In freshwater ponds, the sand is a great host for many insect larva, that act as the clean up crew in oceans... The only problem is that these larva grow up, and turn into large stinging/biting/scary looking adult flying insects, so we can't bring them into the home aquarium.  Sounds like you have a healthy pond there!  Good luck. -Magnus>

Freshwater DSB? Hello- I was wondering if you could use a deep sand bed on a freshwater tank, say for discus. Thanks mucho <yes... you can, but with the understanding that it will not be as diverse as a marine substrate. More for NNR (natural nitrate reduction). Also serves well for plants being kept with discus. Kind regards, Anthony>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: