How Freshwater Deep Sand Beds Work

[Goodcreature]

I know that the poster of this quote is long gone, but if anyone ever wants to know...

Have any of you kept goldfish in a DSB setup? I really love black moors and would love to set up a large 55 or 75g tank with a few of them sometime. I also find the FWDSB approach very appealing. I'm just not sure the two are compatible.

I note that high-flow filters are normally recommended for goldfish (2-3x what you'd normally use for a tank of the same size), yet low-flow (1/2x what you'd normally use) is the recommendation for a DSB. What's the recommendation for dealing with this?

Goldfish in the typical tank require higher flow because they are MASSIVE poopers. The high flow is needed to quickly deal with the ammonia in their waste. However, in a proper DSB, the aerobic layer does most of the biological filtration in the tank, since there's just so much surface area for the bacteria to colonize. The only reason ( as far as I know ) for a slow-flow in a DSB is to allow the mulm (poop and other things) to settle and be distributed relatively evenly along the sand, which greatly helps the bed perform its job.

So, really, depending on how many goldfish there are, you don't need a high-flow filter, since the sand bed will eventually take care of the biological filtration. But, because the sand bed has to mature first, you would need a high-flow filter for only the first three months, after which you could tone it down.

 

[Flear]

goodcreature, ... wouldn't a highflow filter in any age of tank prevent mulm from settling ?

high flow also has high intake, and high intake will accumulate all the mulm instead of the sandbed wouldnt' it ?
just my thoughts on the subject.

 

[Flear]

as i read your posts for "How freshwater deep sand beds work" some thoughts come to mind

what is your recommended gallon/hour filter rate ?

one site listed freshwater at 1/2 tank per hour
a marine listed 10-20x per hour
another site listed the fast water flow prevents mulm from settling (and causing other obvious problems)

tank in mind (DIY round tank) i'm sure that would give fast river type current, don't think rapids, but that's a guess, might actually be that fast

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on your post #31 you mention someone that has a near self-sufficient tank, ... what other info could i find on this ?

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like yourself, an H2S test kit would be great, a very fast search gave no results

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for a deep sand bed, what i found for initial findings suggested grains about .2mm, uniform, ... pool filter sand as suggested as near perfect

i read your comment about grain size.
too large, less surface area for bacteria
too small, toxic gasses may not diffuse back into the water column fast enough and gas pockets may form

continue reading and ...

anoxia points out clay being used for koi, ... like yourself it throws everything i thought i knew on it's head

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i do plan on doing a stress-test for the deep sand bed, all the critters, no plants, and see just how much the bed is capable of handling before toxins can't be processed anymore.

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page 13 in the thread.
you wrote that article for the deep sand bed ?, nice
that was the first article i read on the deep sand bed and have been searching ever since for more info and more importantly, personal experiences

i've found a few on saltwater/marine deep sand beds, but this forum/thread is the first i've seen that talks about freshwater.

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mention of UGF for deep sand beds. (page 14)
i don't like to be a nag for pessimism, but ...

if it's thick enough, i couldn't even guess at how thick that would be, 8", 12", who knows. there may be enough aerobic depth to introduce an anaerobic layer, the byproducts of that anaerobic layer, ...
part of the breaking down of toxic nutrients also brings up H2S, ... that would then be dumped directly into the water column wouldn't it ?, instead of having to diffuse up and be nutrilized before it reaches the water column.

just a thought, no research

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reading other posts...

goldfish vs. plants, ... i dono about good idea vs. bad idea. if it's a bad idea it may not be a 'bad idea' if it's part of a goldfish's natural diet, ... they eat lots, ... so are new plants cheap enough to come by or not ?

invest in some fast growing plants, and lots of them, and duckweed, and whatever else to keep up with the goldfish.

segregate your tank to allow part of it to grow plants (or a seperate tank) till the plants are large and taking over, ... then move them to the goldfish tank/side

i've tried to look up info for goldfish, mostly "are they community friendly", very simple strait-forward question, ... i can't find any info out.

every other fish i've looked up in the hobby, ... are they loners, do they require companions, are they friendly to other community fish, ... loads of answers, ... goldfish, i suddenly get nothing. so i opted out of getting any.
i've no idea about dietary needs

but goldfish i hear would eat most everything they can get their mouths on, ... i've read they will eat snails up to about 1/2". they do go through the gravel on the bottom in my experience (possibly because they were still hungry) so i'd expect blackworms would be tasty treats till they're all gone, for goldfish i didn't know near as much back then as i do now, like now i know they prefer cooler water than tropicals, they did fine in my tank with neons and such through (till they ate them

i hear blackworms are better for fish than tubifex worms (zero personal experience on either), appearently fish love tubifex worms more, but a diet high in those can cause other health problems, ... i guess not that different from eating McDonalds all year round. (no i don't like McDonalds myself)

as for bioload, goldfish like pleco's are far larger a bioload than the standard 1" per gallon rule of thumb

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goodcreature, like yourself, "anaerobic is bad" , then "anoxic is bad", ...
i eventually overcame those, although not too far from the fence that said "anoxic is bad" then i read deedeek's comment about H2S gas bubbles forming if it can't diffuse back up and the water becomes saturated, and i'm right back on the fence.

farther reading in this thread and peoples comments about clay, and packed clay and sand layers ontop of riverbeds that smell clean, and riverbeds with no sandy layers that stink and have dark layers very close to the surface that burp and bubble when stepped on, ... so it's just a health thing i think. and i don't see the fence anymore.

as deedeek mentioned about planaria, there are good, bad, and dangerous kinds, i do want to include planaria, but going to require lots of research and hunting down suppliers or finding them in the wild and then testing them (goldfish are cheap

most all suppliers of critters for the sand ... welcome to canada, such things are all dead or not sold here , i found a single source of blackworms on the other side of the country. thankfully MTS are all over the place and free to come by. and boarders are a good way to buy a bunch of dead critters

 

[Gierling]

I've had my DSB going in my 155 for about 2+ years now.

Just recently survived 5 days of power outage without any spikes in levels.

I really don't think I need my filter running at all.

 

[mesto]

:thumbsup:

Mine has been running for 8 months in my 40B, doing very well, I'm able to do very high light w/o CO2 supplementation due to high fish load and the CO2 from the bed, I think. Also bed helps handle high fish load. I do have to add K2NO3 for the plants because the tank eats nitrates too fast. Not for everyone or even every tank but a neat alternative, at least so far IME.

 

[Flear]

strange curiosites while involved in other aquarium researches

http://www.americanaquariumproducts.com/Nitrogen_Cycle.html
"[FONT=Arial, Helvetica, Avant Garde]A tell-tale sign of Hydro Sulfide production is black areas in the deep areas of sand or substrate, whether freshwater, marine, or especially ponds."

DeeDeeK's tank and her buried gourami (can't spell) the sand in the area turned black. it eventually went back to normal (for that depth in the tank), ... an interesting curiosity to share
[/FONT]

 

[Symbol]

Thanks, Flear and Goodcreature for your thoughts on goldfish vs. DSB. I may hold off on that pipe dream for a while until I can get a non-goldfish FWDSB tank up and running. I'd still like to give it a go one day though.

Also, I'm not sure where you're located, Flear, but I'm also in Canada and recently discovered Boreal Northwest. They're located in Ontario and seem to carry most of the small inverts I'm looking for: daphnia, planaria, blackworms, copeopods, etc. The only thing they don't seem to have are amphipods. Still, that'll be a good chunk of critters to get me started.

Now, I have additional questions!
So, the amazing filtration and bioload capacity of DSBs have been mentioned many times in this thread. The ability to "overstock" tanks due to the DSBs fantastic ability to break down and deal with waste products. Which is great. However, what if I want to understock my tank? Will my DSB starve if I only end up putting 20 gallons worth of fish in a 50 gallons of water? Should I "overfeed" to try to keep all the critters in the sand nourished? Or should I just trust my little glass box to find its own balance?

And, on a related note... will my plants suffer from lack of CO2 in an understocked tank? Any recommendations for dealing with this? Or should I just plan on adding more fish?

Also, if anyone has any good recommendations on South American plants that can be grown emersed (roots in the water, leaves in the air), I'm all ears. (That one's off-topic, I know, but I was just hoping someone might have some suggestions or ideas.)

 

[Flear]

i haven't given up my search on info about the DSB, but it's met some interesting stumbling blocks

plant roots will oxygenate the substrate. this will reduce and may eliminate the anoxic areas in the substrate till you've just got a really deep hypoxic substrate, ... so no denitrification through this method at this point.

plant roots can also directly take in nitrates, as well as ammonium (little talked about, non-toxic cousin of ammonia)
ammonium vs. ammonium, a PH swing if your tank is high in ammonium can cause an ammonia spike. thank you for plants

daphnia in canada i've only seen magna (the rather huge variety, 5mm adult size)
planaria, as DeeDeeK found later in her research, aren't as safe for your aquarium as the hobby would have us believe, so do extensive research (outside of the hobby) to find out what species of planaria you are considering and it's dietary preferences (many planaria have a like of fresh meat - our live fish)

saltwater DSBs don't talk much about CO2
freshwater (thanks to DeeDeeK) she's come to find that through a lot of the bio-chemical actions happening in the substrate it alone can produce a significant amount of CO2, in addition to your fish, this is a good thing.

make sure your CO2 is being used, or disipated out of the tank, as this can lower your PH.
RO water (reverse osmosis) with CO2 alone can bring the PH down to 5.7, under pressure it can go as low as 3.5, thankfully our tanks are not pressurized.

one page i came across while trying to figure out what plant roots did mentioned a test done where they sealed the water surface (layer of plastic) and had emersed plants growing, they noticed the O2 levels in the substrate were climbing.

of the list of freshwater critters, trying to find detritus feeders ... they're not sorted this way (at least not that i've come across)
for the sand bed, Burrowing detritus feeders, ... malaysian trumpet snail, assassin snail, blackworms, tubifex worms (can't find tubifex worms in canada . as for freshwater plankton, doesn't matter how you search for it, every search for live food comes back to marine , it's like the world is prejudiced against us

i'm trying to find freshwater plankton of a size small enough to be minimal concern for fish in the tank, rotifers & phytoplankton. just for my personal searching, this is about what i'm left with. other critters are either unicellular (usually bacteria) or large enough smaller fish will eat them all.

hopefully at work today (call center, so i'm infront of a computer on the net all day , i'll stick to looking up rotifers to see if there are any that will assist with detritus breakdown and/or make a list of sessile rotifers (anchor themselves and live out their life) in the water column, unless it's fish your intentionaly buying from the LFS, i'm pretty sure they're going to be seen as food and will eventually be all eaten up. one lady had a 30 gallon with a single fish (2" i think it was, would have to read that post again), she said it took the fish 3 months to eat all the daphnia in the tank. the fish was more on the carnivores side of the food preference though, so something to keep in mind.

if your worried about low CO2, there are CO2 testers, little drop things that can sit in the tank and give you a good estimate of CO2 levels in there for the short life till they have to be changed.

right now, for a DSB, i want to test to see how deep the hypoxic substrate would get at whatever sand grain size would support the hightest bioload. a mix of surface area vs. porewater (space between the sand for the water to diffuse through it to do it's nitrification)

then i get to find optimal sand grain size to support the highest bioload, and how deep the sand bed is to support this "highest bioload".

going to use a lot of ammonia & nitrite tests for that, and lots of fish till i find i can't add more without raising ammonia and/or nitrites.

hardest part of that test, ... finding the sand sieves. alibaba is great, if you want to buy orders of 100 or more , i only want 1 of each specific mesh size.

it's hard to find info on freshwater Deep Sand Beds, everyone adds plants so how do you tell how much the sand bed is responsible for and how much the plants are handling.

as for concerns of your DSB starving, ... i wouldn't think so, might consider overfeeding at the start so their's extra mulm/detritus, after that, up to you.

i've got about 2" in my tank now (started before i heard about DSBs), i've got plants near smothering half the tank, the neons hide in there so i can't count them ... i cannot see more than a few inches into it at all. the plants are doing fine, ... there is signs the plants want more phosphates though. i've heard holes appearing in their leaves is a sign they've run out of phosphates.

i'd rather have enough phosphates for the plants and deal with algae instead of the other way around, ... so i gotta get more red cherry shrimp

first i started with staghorn algae, in small amounts it's interesting
don't have that anymore , now i've got green thread algae, definitly not a fan, not at all.
it would be nice to have beard algae, but appearently red cherry shrimp will eat that too , ... well if i don't have to deal with thread algae i'm alright with the trade off though.

i kinda went off-track there.

as for your DSB starving, ... in time it will have enough mulm that has fallen into it there should be no problem. at the start, ... well everything is starting at the start, bacteria don't just suddenly appear to fill the sand bed.

 

[Flear]

oh ya, i'm on the west coast, but thanks for the link to that website , now i know 2 places in canada blackworms can be gotten from. and they've got other freshwater plankton, , thanks

 

[Symbol]

Yes, I'm planning on doing a bunch more research before I toss any planaria into the tank. It's not even set up yet, so I still have lots of time to get my research groove on. Boreal sells a couple different types of planaria, so I'll see what I can find out about them before proceeding.

As for your plankton search... If you can order from Boreal (which may not be feasible, I realize) they sell a pond life culture set that might be worthwhile. It includes daphnia, rotifers, hydra planaria, paramecium, euglena, amoeba, and vinegar eels. Now I realize you probably won't actually want all of those things in your tank. But they seem to come with each variety in a separate container, so you can just add what you want and leave the rest out. It would get you your rotifers anyway. And the euglena are single-celled, but being eukaryotes, they're gonna be way bigger than most bacteria. It'd be a start anyway.