To DSB or not to DSB!!!

Discussion in 'Beginner Discussions' started by marsbrat, 19 Apr 2011.

  1. marsbrat

    marsbrat

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    Hi all,

    I have a DSB about 600 x 250 and about 20cm deep. I have course sea sand in the bottom 3/4 and a finer sea sand on the top 1/4. Water flows over at about 25mm over the bed and feeds back with an Eheim compact 3000 pump. Is this the correct manner? Do i have enough flow? Should I perhaps add another 3000l return pump to increase circulation rate over the DSB.

    My reason for asking. My tank is now 4 months old. I do waters changes every 4 to 6 weeks, and I seem to have a major algae problem. Today I had the water tested and found Calcium lacking, phosphates ok. Bought some Calcium additives and added bicarb to my return RO unit.

    I want to get rid of the green. Is this going to take forever, can I hurry it along?

    Please help!!!

    :yeahdude:
     
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  3. Robert.

    Robert.

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    The main purpose of the deep sand (DSB) is to provide nutrient export by providing a stable home for nitrifiying bacteria to convert harmful toxins that pose a danger to fish and inverts to less harmful nitrogen gass. I think :)

    The DSB should contain a relitavily small substrate ( the grains of sand should be shugar fine) as this increases the surface area. Also ur DSB is a bit to small, to my knowledge the weight of ur live sand should account for 10% of the total weight of ur tank.

    Also it is VERY VERY important to make sure that the flow of water isnt going through the sand but just gently across as this will defeat the perpose as the enviroment were the bacteria live will be disterbed.

    I learnt all this and much more from supplied information in these forums, found on this website:) - just go to the forums page and scroll down ull see biological filtration,
    there ull see a sticky on DSB.:thumbup:

    Hope i helped:blush:
     
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  4. robertkukla

    robertkukla

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  5. Tony

    Tony

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    I've never kept a DSB. I use bacteria and carbon dosing to lower my nutrients. This has always worked for me
     
  6. marsbrat

    marsbrat Thread Starter

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    Thanks...I think...
     
  7. Reef Maniac

    Reef Maniac MASA Contributor

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    Agreed - there is an optimum particle size grading, but over all, it should be very fine.

    Even more important, though, is that the deep sand bed must be ALIVE, with various sand-living critters to "turn over" the sand, and to allow water movement through the sand bed at a rate that will maintain the anaerobic conditions required to make it work. Just having a thick layer of sand will not do the trick, and that's why I prefer to refer to it as a DLSB (Deep Live Sand Bed).

    That course sand on the bottom of the bed is also not helping.

    Hennie
     
  8. marsbrat

    marsbrat Thread Starter

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    Maybe to clarify, my "more coarse" sand is about suger size and the fine sand is even finer!

    What do u suggest in terms of giving it life? I have a few crabs running about but they tend to climb up and down everywhere!
     
  9. Reef Maniac

    Reef Maniac MASA Contributor

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    Crabs are predators, and I would not have any on my DSB if I could help it - neither would I "store" any predatory fish (such as wrasses, blennies, dottybacks, etc) in my DSB containing sump.

    Well, the easiest is to add one or two pieces of live rock, preferably fresh and uncured (but then you must take it slow, and not over do it, because the uncured rock could cause a mini cycle if your setup is not mature enough). You could also ask fellow aquarists for donations of small amounts of sand from established DLSB's (just a cup full would be enough). Lastly (and IMHO the best way) you could arrange with a LFS to allow you to collect some of the "grunge" off the bottom of the boxes when they receive a delivery of live rock. When opening a box of LR, there is invariably a large amount of dead and dying critters on the floor of the box - if you can get these worms and other critters into some fresh salt water you can usually save a lot of them, and then it's pretty easy to remove the harmful ones, and place the rest into your DSB compartment (preferably already housing some live rock as well)

    Hennie
     
  10. marsbrat

    marsbrat Thread Starter

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    Thanks Hennie...

    Live rock on the DSB, I assume small pieces? Must they be covered in water? Small flat pieces???

    I have taken the crabs back out ant put into my tank...

    Snails in the Sump?
     
  11. Reef Maniac

    Reef Maniac MASA Contributor

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    Well, that would depend on your sump, I suppose.

    My sump is deep enough that I have perhaps 300mm of water depth above my DLSB, so for me it's easy to keep even large pieces of LR in the sump. Remember that your DLSB does not have to be much more than 100mm - 150mm deep, depending on how course the sand is (finer = less thick)

    It is preferable to have the LR suspended above the DLSB, but obviously still submerged. If you cannot do that, you can just leave the rock on the sand, or even half buried in the sand, for a few days - this should be enough time for many of the goggas to migrate into the sand.

    Hennie
     
  12. marsbrat

    marsbrat Thread Starter

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    Here is a pic of my DSB...

    [​IMG]
     
  13. Reef Maniac

    Reef Maniac MASA Contributor

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    Do you need all that empty (waterless) space to accommodate the rundown from your display tank? If not, why don't you just raise the water level in your sump?

    When my return pump goes off the sump fills up to within about 3-5mm of the top, but that's OK, because nothing OVERflows. This way, the normal operating level of the water in the sump is high enough to allow for lots of large pieces of live rock to be kept in there as well (as well as various corals that I just don't have space for in the display tank...)

    Regarding the sand in your sump: I would just mix it all together, and not have two different graded layers. Finer sand on top would result in the sand bed becoming anaerobic at a shallower level (thus increasing nitrate export), and would prevent more detritus from settling/being caught in between the courser sand particles, which is good, BUT the larger "voids" between the courser particles on the bottom would require a deeper sandbed for it to become anaerobic, and would be detrimental to small sand-living organisms trying to move through this layer.

    Hennie
     
    Last edited: 21 Apr 2011
  14. xtreme

    xtreme

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    :slayer: HIJack sorry. Hennie can I use dune sand or is that to fine and mine is about 150mm deep and there is a carpet of crap forming on top of it

    [​IMG]
     
  15. Reef Maniac

    Reef Maniac MASA Contributor

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    No, it's not too fine, BUT there is a much higher chance that it could be polluted. Also, it would not contain any (or at least not many) of the beneficial "filtration" bacteria.

    That should be fine. Depending on the length of time that it's been set up, a correctly sized DLSB should develop smallish black areas towards the bottom of the sand bed. If the black areas grow very large, it is an indication that the sand bed is perhaps too deep - on the other hand, if not even small black zones develop after a few months, it is an indication that the bed could be too shallow for the particular sized sand particles you have in the bed (or that water is flowing through, and not over, the sand bed).

    One thing of concern, though: looking at the photo, I do not see any worm tracks in the sand. a properly live sand bed should have signs of worms and other critters visible in the sand when looking through the glass, and without the correct "life" in the sand bed it will not function properly for very long.

    I see - the red stuff is cyano bacteria, and is an indication that your system has excess nutrients, and/or the flow over the sand bed is perhaps a little too slow. Having said that, cyano bacteria is an excellent natural filter, and if it only grows on your sand you have nothing to worry about - I've had varying quantities of cyano, and hair algae, in my sump for many years now, and consider them part of my tank's ecosystem. I would suggest that you just regularly remove the cyano mats, and thus export all that captured nutrients...

    Hennie
     
  16. xtreme

    xtreme

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    thanks Hennie

    Yip its cayno with other stuff too almost like dust, I cleaned the glass to take a pic
    No black spots yet, running for 5 months now, there is gogas yes but the bristle worms is in the LR or under lol. There is no cayno in the DT and yes high in nitrates, doing vodka dosing with MB7 at the moment, feeding as little as possible. Lights also off and my Bobby (Purple tang) doesn't want to eat algae anymore he is fat and lazy only want pellets and nori lol
     
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