Dead spots

Discussion in 'Sand' started by Hevgotdat4u, Jul 6, 2009.

to remove this notice and enjoy 3reef content with less ads. 3reef membership is free.

  1. Hevgotdat4u

    Hevgotdat4u Fire Worm

    Joined:
    Mar 7, 2009
    Messages:
    173
    Location:
    New Haven, CT.
    I've heard in the LFS's that you dont want to much sand in order to avoid dead spots can you have dead spots in 2-3 inch beds and if so how do you prevent this.
     
    Hevgotdat4u, Jul 6, 2009
    Hevgotdat4u, Jul 6, 2009
    #1

    2. Click Here!

  2. reefer Bob

    reefer Bob Montipora Digitata

    Joined:
    Jan 19, 2009
    Messages:
    1,070
    Location:
    Largo, Fl
    I dont think the sand depth matters when having dead spots. A dead spot is from not having water flow in that area. Since you have a good variety of sand sifting stars and eels and gobies, I dont see you having a problem. If you get a spot where sand dont move then waste will gather there and when it does move it will let all the waste in the water.
     
    reefer Bob, Jul 6, 2009
    reefer Bob, Jul 6, 2009
    #2
    1 person likes this.
  3. Phayes

    Phayes Aiptasia Anemone

    Joined:
    Feb 25, 2008
    Messages:
    584
    Location:
    Ontario, Canada
    Yeah, dead spots are caused by lack of water flow in that area and not the depth of the sandbed.
     
    Phayes, Jul 8, 2009
    Phayes, Jul 8, 2009
    #3
  4. greysoul

    greysoul Stylophora

    Joined:
    Apr 19, 2009
    Messages:
    975
    Location:
    Albuquerque
    Dead spots on the surface of the sand is a flow issue. If you're getting bad alage blooms on the sand in one region of the tank it's probably because detritus is getting trapped right there. A small powerhead or realignment of those you already have can fix the problem.

    The other issue is anoxic regions in Deep Sand Beds. By design a properly established DSB should have a "dead zone" in a plenum at the bottom of the tank. Disturbing that region can in a worst case scenario kill the tank.

    An unintentional or poorly made DSB can develop dead zones that can be a bigger problem. 2" should be fine, 3" is pushing it, 4" or deeper and you will have anoxic regions in the sand that could lead to trouble.

    Also, anoxic dead zones can build up under rock in as little as 1" or less of sand if there's no natural flow through the sand. It's always a good idea to have your live rock on the bottom of the tank before adding sand. Even if it's not most live rock is so porous that the sand under it should be fine, but large dense flat rocks are riskier than well shaped airy rock.

    In the case of anoxic zones in deep sand do all you can to avoid disturbing them. If one does get mixed up you'll smell a sulfurous smell and the water may get very cloudy. If that's the case an immediate 25-30% wc is called for, more if you can, as well as carbon filters and a strong skimmer.... keep an eye on the fish and inverts, and hope for the best.

    I have some deeper areas in my tank and I make it a point to siphon them heavily during WC's to prevent any release of bad stuff into the tank.

    -Doug
     
    greysoul, Jul 12, 2009
    greysoul, Jul 12, 2009
    #4
    1 person likes this.