Too much return flow,

Discussion in 'General Discussions and Advice' started by magman, 1 Sep 2009.

  1. magman

    magman

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    Is it possible to have too much flow over a DSB, I am moving 6000l/hr from the return, now do you think this is too much over a 100x45 DSB, my point in that most of the detrus going to the sump does not have a chance to settle on the bed?
     
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  3. jacquesb

    jacquesb Retired Moderator

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    Yes, it indeed is possible, magman. Our tank's return flows should be between 1500 litres per hour, and 2500 litres per hour....

    Otherwise, the detritus does not get to settle, as it should, in the sump's DSB (on the sump's DSB).... and the sump does not get to do it's job (ie clean the water) - and you will have "dirty" water being returned to the display tank....
     
  4. Falcon

    Falcon

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    well yes and no,this is relative and there are two main factors to take into consideration..think of the detritus right it starts in your tank and keeps getting blown around from tank to sump UNTIL THE SKIMMER REMOVES IT:thumbup: which is what we want in reality we dont really want detritus to settle anywhere.

    so 1st make sure that the dsb sand itself is not being blown around.

    Then make sure the detritus is not settling in your display tank either, by having lotsa flow in your display.

    this would work brilliant in a sps system especially as you have high flow rate in your dt.

    oh yes and make the dsb atleast more than 15cm and with ultra fine sand like playsand to make sure that it does indeed become anaerobic at the bottom layers.
     
  5. seank

    seank

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    Reggies play sand has a tendancy to do that, especially if your buffer is cut too low, meaning, your sand is filled to the rim of the overflow section of glass;)
     
  6. ADVdiver

    ADVdiver

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    Magman a general rule of thumb is that the flow through one's filter should be between 1 and 3 time's per hour. I find the slower the better it all comes down to contact time.
     
  7. brentnorm

    brentnorm

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    Agree, the more contact with your sand bed and skimmer the better.
     
  8. Tobes

    Tobes Retired Moderator

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    I'd say 3 to 5 times is better.
    Posted via Mobile Device
     
  9. ADVdiver

    ADVdiver

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    Depending on your application this may work for you.
     
  10. aslam

    aslam

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    Correct me if I misunderstood,do we want detritus building up on our dsb's,or should we have cuc to take care of this should detritus does build up on the dsb.Is it advisable to touch the surface of the dsb.
     
  11. Mekaeel

    Mekaeel Moderator MASA Contributor

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    Aslam. We got to try our very best to have minimal detritus settlement anywhere in our systems including our DSB.
     
  12. Mekaeel

    Mekaeel Moderator MASA Contributor

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    My choice in terms of flow from sump to tank is low.
    Take for eg. my system, i probably have about 1000lph flowing from my tank to my sump.
    The reason why i like it so low is because of my feed pump on my skimmer.
    My feed pump is 1000lph, and I feel anything going faster than that, is a waste. Not all the water passing is going through mechanical filteration (skimmer).
    This is what leads to detritus settlement all over the sump, thus causing Nitrate and Phosphate issues and then nuisance Algae which takes ages to resolve.
     
    Last edited: 1 Sep 2009
  13. ADVdiver

    ADVdiver

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    perfectly put Mekaeel
     
  14. magman

    magman Thread Starter

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    I am going to start a bun fight now,

    I am running between 12x and 15x return flow, and I think it is exceptional. There is so much more natural flow in the tank, and everything looks so much more natural.

    The powerheads are all on the bottom of the tank on the rocks, except one, wich is at the surface pointing up to break the surface.

    The tank is clean from detrus, my only concern is where is all the detrus, tonight I am going to make a detrus trap under the baffle, and empty it when I empty the skimmer.
     
  15. ADVdiver

    ADVdiver

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    Its not a problem to do this through your aquarium but you will flush your filter with that flow
     
  16. seank

    seank

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    Just make sure you clean the trap daily, otherwise it could get clogged up, and flooding can occur
     
  17. davidfr7

    davidfr7

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    What if you make your glass a little higher for the water coming out of the dsb. Wont that allow for more settlement
     
  18. Falcon

    Falcon

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    WHY DO YOU WANT IT TO SETTLE ON YOUR DSB????!!

    read meks posts i agree completely,you want your skimmer to take it all out.

    as for contact time well its relative,if the water contains 5ppm of nitrate then that 5ppm is spread evenly through all the water and when its removed from lets say half the water then the other half contributes half of its 5ppm to the nitrate free water effectively simply making all the water contain 2,5ppm nitrate.

    this is the same as the dsb removing 2,5ppm from ALL THE WATER.

    THE MAIN CONCERN HERE IS THAT YOUR DSB SHOULD NOT BE OVER OXYGENATED AT BOTTOM.so make your dsb a bit higher and add in a few small pieces of live rock to prevent any sand geting too diturbed and bobs your uncle!
     
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  19. jacquesb

    jacquesb Retired Moderator

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  20. Falcon

    Falcon

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    just to verify how i got to this conclusion,in my nemmie tank where i have no power heads in tank so all my flow is provided via return pumps i have a 1750lt pump and a 2000lt pump running water through a small 25lt dsb and it works brilliant,macro algae cant be grown in that high flow but the dsb is working for the last few months as my nitrates are zero and i have no phos remover(will get soon) but still my algae growth is non existant and i only have to clean the glass once every two weeks.
     
  21. Hermanus

    Hermanus

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    I'm returning with a 2500l/h pump and a 3000l/h pump in my 1,8m X 0.6 x 0.6 total water volume is plus minus 650l, the lift is 2m so both pumps will deliver Les than what thy are rated for, The 2500 will do about 1200l/h and the 3000 will do 2400l/h. So it is what 3600l/h which gives me 5-6 times total water volume over dsb. Is this OK?
     
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