How much sand??

Discussion in 'General Discussions and Advice' started by Schalkdk, 19 Mar 2010.

  1. Schalkdk

    Schalkdk

    Joined:
    15 Mar 2010
    Posts:
    63
    Likes Received:
    2
    Location:
    Durban
    Hi. I was just wondering, how much sand I should use in my display tank. And why? I have noticed some people barley cover the base of their tanks. Would it not be a better idea for biological filtration if o use a thicker layer of sand?
     
  2. AdS Guest




    to hide all adverts.
  3. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,165
    Likes Received:
    1,232
    Location:
    Centurion
    You got 3 options


    1. Barebottom, ( I do not like it.)
    2. Shallow sand bed, 2 or 3 cm thick layer.
    3. Deep sand bed in display, about 15cm deep in display, but be careful, rocks must be very stable and no burrowing critters, else you will have a rockfall.
    Option 2 is the best.

    And it should be a fine substrate. not crushed coral sea shells or any coarse big items.
    Playsand or aragonite is ok.
     
  4. crispin

    crispin

    Joined:
    22 Jan 2008
    Posts:
    12,223
    Likes Received:
    160
    Location:
    Lilliehammer, Norway
    it really depends on what you want to achieve and how you plan your tank. A sand bed is advantages in that it allows an environment for micro critters and microscopic life to live in. These are very good at helping to process the waste that falls to the bottom, most often fish poo and uneatefood (although thats a drastic simplificion). A sand bed also allows for a spefic environment for fish and certain tank mates to live in (sandsifting goby's, wrasses, star fish etc etc etc). A shallow sand bed should be around 5-8cm of fairly fine rounded pieces of aragonite.

    A bare bottom tank is used as its far easier to get that detritus OUT the tank by using heavey pumps and getting it into suspension, over the overflow and sorted out in a sump. Skimmers, DSB, etc all help process it. Many people with SPS dominated tanks, which like a heavey flow use this as you can keep the water cleaner, easier.

    A in tank deep sand bed (DSB) has the advantages of a SSB in the top layers, but the lower layers which are oxygen deprived also have a nitrate conversion factor. These sound great, but are NOT that often used as the macro life (sand sifting stars, burrowing wrasses etc) often disturb the lower areas which are detrimental. They are also quite expensive to set up as idealy you want 10-15cm of substrate which on larger tanks gets expensive. The lower areas can also look unsightly with dark areas and some find that distracting. The advantage of a in tank DSB is that you have a good foot print and often get very stable water quality.

    my personal choice is 8-10cm aragonite 1-2mm in particle size where the particles are rounded and NOT sharp. But thats an expense, although i feel its worth it for the diversity of life, environment for critters (macro and micro) and can be bracing white.

    Sand shifting starfish (burrow under 1 mm substrate and then cruise at night) or similar things are great at keeping the top layers clean
     
  5. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    I beg to differ - this will depend on the type of reef tank you want to keep. A bare bottom is the best for the really hard-core SPS tank, but other than that a deep live sand bed wins hands down, IMHO.

    Hennie
     
  6. RiaanP

    RiaanP Moderator

    Joined:
    11 Aug 2008
    Posts:
    23,165
    Likes Received:
    1,232
    Location:
    Centurion
    Yes, Hennie,

    But

    If you have a remote deep sand bed, and your Display tank is only 450mm deep, then using 150mm of that for sand is such a waste of real estate. Even on a 600mm deep tank, then 25% is sand? Unless you plan a tank and built it so that it is deep, (750 to 800mm) and that the cabinet can hide most of the DSB.

    Also a remote DSB is better, than an in display DSB. Because all fish that filters the sand like gobies, they will eat the live in the sand you want for filtration. Also disturbing the DSB too much. Also all liverock must be securely supported, else anything that decide to dig, will and can create a rockfall. Also generally the sand directly under the rocks are not "effective" as in acting as a DSB as you would want it. Have to subtract that from the sand footprint to get the real size of your DSB.

    Big pumps, and sand, you get sand storms. Blowing and moving, making heaps where you do not want it. Yes that is why for SPS I can see why bare bottom is preferred.
     
  7. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Well, I thought that was obvious ;)

    On the flip side of your argument, many people buy tanks which are too deep (750mm - 800mm +), and then cannot reach the bottom to do cleaning, etc. Having a nice, deep sand bed would lift everything to a nice, manageable level, and boost the amount of light reaching the corals, as a bonus.

    I do agree that a 150mm thick DLSB in a 300mm high nano would look quite odd. Of course, with the correct (fine) sand grading you only need between 75mm and 100mm of sand thickness for it to start operating as a DLSB...

    But that would only be a problem IF you had such fish in the tank. I regularly advise aquarists to not keep gobies, wrasses, etc. in their tanks containing a deep live sand bed, if the DLSB is to operate as a filter. This is part of having a balanced ecosystem.

    On the other hand, IF you really wanted to keep a few wrasses, I would recommend that you still have a medium to deep (50mm - 100mm) sand bed in the tank, because these fish bury into the sand every night and it's unnatural and stressful to keep them in a tank with either no sand, or a very thin sand bed. In this case, I would certainly also run a remote DLSB, as the sand bed in the tank would not perform adequately as a bio-filter (although it would still do SOME filtration)

    Agreed - that is a must, but do to so is neither difficult nor expensive, so there is no reason not to do so. I personally cut rings from a 150mm - 250mm diameter PVC pipe, drill large holes into the sides to ensure proper flow & movement of the infauna, and then just push these rings into the sand, until they reach the bottom glass. If you make the rings high enough that they protrude about 5mm - 10mm above the sand, you also solve the problem of the "dead zones" below the rock.

    Agreed, but that also goes for the shallow sand bed :whistling:

    Once the tank has settled in, and there is a good growth of bacteria & micro algae in the sand, it can withstand pretty strong water movement. My tank has about 30 000 liter per hour flow in it (thanks mainly to the Polario), and if you have not seen it yet, here is a link to a couple of video clips showing this movement. Even with this flow, there is absolutely no disturbing of the DLSB - but one must obviously not aim the pumps directly at the sand...

    Hennie
     
Recent Posts

Loading...
Similar Threads - much sand Forum Date
How much Live rock and live sand? New Members 26 Feb 2008
This is for all those who have to much money Reef Hunters 11 Sep 2016
How much salt? Beginners 19 Jul 2016
My first marine tank... much needed advise Beginner Discussions 21 Sep 2015
New, broke & reading way to much. New Members 29 Mar 2015
How much light is too much? Lighting 16 Feb 2015
lighting is it too much. General Discussions and Advice 25 Nov 2014