Freshwater Deep Sand Bed (DSB)

Yikes, I've never tried this, I hope it doesn't post huge.

freshwaterdsb003.jpg


So, as you can see, I know nothing about aquascaping, but that's not the point for me. All I want is a healthy little waterworld, with happy fish and plants, and at this stage (3 weeks since setup, I think?) it seems like it might work out. You can't see them, but there are

5X black male platies
1X praecox rainbowfish (more as soon as I find some)
8X habrosus dwarf cories
1X albino Ancistrus pleco

Plus a plethora of snails and blackworms. Besides more rainbows, I may consider adding either cherry shrimp, dwarf frogs, or peacock gudgeons. I believe having the substrate full of living blackworms will make it much easier to keep creatures which are generally hard-to-feed in a community setting. If the DSB turns out to be all it's cracked up to be, I may even add all three of those things! Oh, and I must definitely have at least one marimo ball, LOL.

One last note, I've never had good luck with cories, but I couldn't resist these little dwarfs in the store. Even after accidentally dropping one of them on the carpet (rats!), these cories have acted healthy and happy from the start. As soon as I put them in the tank, they started snuffling around in the sand, unlike all the cories I've had before, who always hid. I hope that is an indication that I'm actually doing something right.
 
Thats some great aquascaping and i love the tank.
 
That is so kind of you, Fishfriend1, I was slightly insecure about displaying my little project, due to the experimental nature of the DSB in freshwater. I have just posted this chart elsewhere on the forum, but I am going to repeat myself once again:

aquaticsubstrate.jpg


For further info on this subject, please visit DeeDeeK's great thread called, "How Freshwater Deep Sand Beds Work". Thanks all for looking.
 
So how goes it with your DSB? It sounds very interesting. This is a good thread.

By the by, your dirty gravel sounds like it is jumpstarting the anoxic/anaerobic zone by providing food for the anoxic/anaerobic bacteria getting established. Don't forget that all living things use roughly the same elements and when they decay they release them. So there'll be some mineral nutrients like iron, etc., which are reduced and rendered soluble thus becoming available for rooted plants. Plus, hydrogen sulfide released by decay and sulfate reducing bacteria in the anoxic zone diffuses into the anaerobic zone above, where nitrate reducing bacteria like the common thiobacillus denitrificans oxidize it.

Deep sand beds are boosted by material decaying and introducing nutrients into the system. My latest, a 7 gallon invert tank's sand bed is mixed with a small fraction of compost based potting soil, which definitely decays in the sand. It sometimes bubbles but there's really no harm in that.
 
Thanks for explaining it here DeeDeeK, I don't have as firm an understanding of the process as you do.

I have read a few things since setting this system up that warned against doing exactly what I did - putting too much decomposing matter (mulm-filled gravel) down in the anoxic zone. But it must not be such a huge sin as I was led to believe, because nothing went terribly wrong after all.

I got some dark areas in the sand and a good amount of bubbles, but these do no harm, I just think of them as evidence the DSB is working. I believe a mild sulfur smell I had for about one or two weeks was the only real consequence, but that was no big deal, and then it went away entirely. Ammonia is still 0, Nitrites 0, Nitrates under 10. The fish, frogs, snails, worms, and plants are very healthy.
 
Well, too much decomposing matter is a problem but since you didn't have a problem, it wasn't too much! Unless you considered the sulfur smell to be a problem 'cause surely the smell was from all that gunk decaying. It coulda stopped stinking because that layer ran out of sulfurous gunk to spew or, and I believe this is more likely, enough various sorts of sulfide-oxidizing bacteria established themselves in the sand above the stinky layer.

Someone suggested priming the DSB with earthworm castings, which I sorta liked but the more I think about it the more I like it. It would help jump start the DSB, especially nutrient-wise, but only add a little organic matter. So you could use a bunch of it and not worry about H2S and other sulfurous stinks. Hmmmm...
 
I believe you're right, all I needed was the right bacteria at the right levels, and that just took a little while to build up. It smells like a forest floor now - hard to describe. Similar to that earthy smell you get after rain, which I've always liked. I think it comes from all the soil I used in the DSB, I guess that's the smell - "wet soil". Heck of an improvement over sulfur!
 
I asked a biologist friend about sulfur from decay and he explained that in the absence of sulfates anaerobic bacteria produce hydrogen sulfide and CO2 as they digest proteins from decaying organisms. How this is done I'm unclear on but it has something to do with cracking the proteins and getting energy from that process.

Oh, have I mentioned than here in San Francisco, freshwater DSBs are not experimental but are common practice? There's even an LFS where every tank has a planted DSB. The fish are sometimes heavily stocked and they're very healthy. Anyhow, a great number of his customers (yours truly included) learned from him how to do it. He doesn't use critters to oxygenate the sand but plants alone will do the trick. Worms and snails should improve the performance but they aren't strictly needed. They are very cool, however.

By the way, Anoxia, I like the photo of your tank. It's lovely.
 
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