Freshwater deep sand bed?

  1. inignought Initiate Member

    I'm thinking of setting up a DSB (5") in freshwater. I'm going to use tons of MTS ,plants(Vals) and fish that stir sand. I want it to be deep so the anaerobic bacteria that remove nitrates build up like a SW DSB, but i dont want the pockets of toxic gas that all types of sand stirring critters in SW help disperse. I'm using aragonite 60 lb fine, 30 very coarse in a 60 gal hex, going to stock with rift lake cichlids. Has anyone pulled this off, is it even possible in FW? Anyone know of any other burrowing critter that wouldn't be massacred by the fish? I'd appreciate any info you have.
     
  2. Butterfly Moderator Moderator Member

    Most freshwater burrowing snails (MTS) only aereate the top inch or so . Five inches is pretty deep for freshwater sand.
    Horseface ( http://www.loaches.com/species-index/acantopsis-choirorhynchus ) loaches and Dojo loaches( http://www.loaches.com/species-index/weather-loach-misgurnis-anguillicaudatus ) will some times burrow but not always . that's the only fish I can think of right now. Kuhlis will dig in the sand and sift it through their gills to get microscopic critters growing in the sand and left over food. They like most loaches prefer to be in groups of three or more.
    The dojos and horseface both need lots of bottom space.

    Carol
     

  3. kazvorpal Initiate Member

    Many people have an exaggerated sense of how much "sifting" should occur in a deep sand bed.

    The kind of sifting you guys are describing would actually reduce the effectiveness of the setup.

    Deep sand beds are supposed to be stagnant, that's the whole point.

    Only the very surface needs to be sifted, and only in a very minor way. In fact, that sifting is mostly for the benefit of the saltwater tank's surface organisms, so if you aren't going to have those in a freshwater version, it becomes even less imperative.

    The kind of sifting some people have started assuming a saltwater DSB needs is actually enough to be harmful to the process. For example, sand sifting stars are bad for a deep sand bed. It can function with them, but the SSS is actually sifting out the smaller organisms that are good for the bed, while it does nothing beneficial, itself.

    Likewise, the people who advocate stirring a small segment of the bed regularly, in order to keep the bottom from building up toxins, are completely failing to understand the concept. That, too, does nothing but undermine the whole purpose of a DSB.
     

  4. Butterfly Moderator Moderator Member

    There's a world of difference in sand in a freshwater tank and saltwater. Deep sand that isn't stirred in freshwater can cause many problems even fish death.
    carol
    This thread is almost 2 months old. I imagine the OP has decided what they want to do :)
     

  5. David C Well Known Member Member

    Your best bet would be to look up the exact species of bacteria that feeds off nitrate and then research if it can survive in FW or if it requires SW. I would love to hear your results, I've often wondered if this would work.

    Dave
     
  6. pepetj Well Known Member Member

    I have a DSB in my 145gal FW tank that I figure holds 100gals of water (fish, plants, rocks, substrate use the other volume). I have a Eco-Complete/Natural River Sand (6:4 ratio) substrate that goes from 4 to 6 inches depth. I used to stir it while the tank was not mature. Once it reached 8 months old I stopped doing that because it turned heavily planted at that time. If you keep plants, no problem should arise. If you have no plants (or are lightly planted) then... beware of sudden Sulfuric compounds (gases) wiping out the bio-load.

    SW is a whole different ball game. I do have 6" depth DSB in my Nano Reef.

    Pepetj
    Santo Domingo
     
  7. David C Well Known Member Member

    So Pepe, you say it's a strain that can't survive in FW? I guessed it might be, but I've always wondered anyway. Haven't wanted to chance it with my own tanks :)

    Dave
     
  8. DeeDeeK Initiate Member

    I keep a fw dsb, heavily planted, medium light, no CO2. I've never stirred it for the last two years until I recently took a few samples of the deeper sand with a turkey baster to give 'em a sniff 'cause there was so much black sand.

    I got bubbles but no rotten-eggy smell and the black sand just smelled like garden soil, and no fish died or acted sick in any way.

    My nitrate readings haven't gone past 10ppm in over a year. There are plenty of fw bacteria which use nitrate and some of them use it to burn hydrogen sulfide.

    here's an excerpt from a post I made on aquariumcentral.com, in the thread "How Freshwater Deep Sand Beds Work," in the general freshwater forum:

    Autotrophic bacteria such as Thiobacillus denitrificans and Paracoccus pantotrophus can function aerobically, or anaerobically using nitrate as a source of oxygen are examples of especially handy bugs for the biofilter as they denitrify NO3 AND oxidize H2S, and Thiobacillus novellus, which is strictly aerobic, is handy as an H2S oxidizer too. There are many other similar handy microbes which take up residence in these environments, and they aren't from especially rare or exotic genera (plural of genus). Some of the bacteria also consume fatty acids and other organic compounds which come from anaerobic decay.