what size return pump?

Discussion in 'Pumps and Waterflow' started by RiaanP, 20 Nov 2008.

  1. RiaanP

    RiaanP Moderator

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    On a 500L tank, what size or liters per hour rating return pump should be ideal from the sump to the tank?
    I do not want a sandstorm DSB.
     
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  3. Mekaeel

    Mekaeel Moderator MASA Contributor

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    What is the height from the sump to the top of the tank Riaan?
     
  4. RiaanP

    RiaanP Thread Starter Moderator

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    ah, yes, very important part I forgot.
    From bottom of sump to top of tank - 1.4m
     
  5. Mekaeel

    Mekaeel Moderator MASA Contributor

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    A Lifetech 2500lph pump should be fine, taking head loss into consideration.
     
  6. Quinton

    Quinton Smarty-pants Newbie

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    Ideally you want a sump design where you can redirect some of the flow around your DSB. That way you can fine tune your DSB flow rate, and have a higher turnover return pump. Personally I'd go for more like 10-15x, i.e. 5000-7500 l/hr effective, which given a head of about 1.4m means you need a pump nominally rated at more than this.

    As an example, here's the flow graph for a pump nominally rated at 450 l/hr, but with a 1.4m head it only achieves about 300 l/hr.
    Info: Pump Head vs Flow Rate - Overclock.net - Overclocking.net

    In summary, I think you'd be well served by a Lifetech AP5800 or similar pump. It's rated at 12,000 l/hr, but probably achieves around 8000 l/hr with a 1.4m head and some piping, which is around 16x your system volume. Provided of course that you divert some of that flow around your DSB, as it's probably too much flow for that.

    You could also install one of those clever-dick flow mechanisms at the outlet (I forget the name) to create varying, turbulent flow in the display tank.

    Q
     
  7. RiaanP

    RiaanP Thread Starter Moderator

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    Quintin
    what and where can I get those "clever-dick flow mechanisms at the outlet"
    I looked at the squid, but can not find it in Pretoria.
     
  8. Tobes

    Tobes Retired Moderator

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    I would say it all depends what you want or want to achieve with it. My new tank's head will be only 1.2 high and I split the return pipe in to 2. One side is a normal return pipe on the far end of the tank and the other one is attached to a live rock stand drilled full of holes. I'm using a 3000lph Rio Hyper flow pump. Tested it the other day and it works the bomb :thumbup:.
    You want good flow inside your tank, not a too fast turn over. Your skimmer will remove more stuff from the water and the flow over your DSB won't be too strong. Just my opinion anyway :)
     
  9. jacquesb

    jacquesb Retired Moderator

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    I would say a 2500 l/hour might be SLIGHT overkill for a 500 litre tank. 1800 to 2000 litre / hour will be more than good enough....
    You do not want too fast flow through your sump.....
    Otherwise the sump's filtration does not get a chance to work as it should.....

    And oh yes - you want to aim for a 2 to 3 times SUMP water volume turn-over, in sump water flow....
     
  10. bob o

    bob o

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    Hi guys.

    I have the same question here.

    I too have a 500l tank.

    Was think of getting a dc pump.

    What would be suitable?

    Jacod dct 2000 or jacod dct 4000?
     
  11. dubediver

    dubediver

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    Great thread , sitting with same issue. Thinking of upgrading return pump. Like the D.C. Cause you can adjust flow nicely. Was looking at small red devil, wonder how that compares to the Jacod.
     
  12. dubediver

    dubediver

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    My return runs across my sump then up, would this increase the head height ?
     
  13. dubediver

    dubediver

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    IMG_4578.JPG
     
  14. RiaanP

    RiaanP Thread Starter Moderator

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    Go for the bigger pump. Can always run it at half speed being a DC pump.

    Yes, you got two 90 degree elbows. If it is a problem, I would remove the blue horizontal return PVC pipe and replace it with a longer flexible hose. Do admit that the blue pipe do look neater.
     
  15. RiaanP

    RiaanP Thread Starter Moderator

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  16. dubediver

    dubediver

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    About 15cm, just a touch too shallow. I definitely think my return is too low, , but the tank is running nicely, so am thinking to wait a bit, unless I find a bargain second hand.
     
  17. Forbes

    Forbes

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    Hi Guys, stupid question, why cant you divert all the flow to the return pump chamber, bypassing the DSB, and then branch off the return line to the DSB with a ball valve to control the flow.
     
  18. RiaanP

    RiaanP Thread Starter Moderator

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    Normally the flow over the DSB is anyway too low. Most guys will get better results by adding another pump to the return chamber pumping directly back to first chamber. To increase the total flow across the DSB.

    Excess settlement is a problem on the DSB.
     
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  19. Forbes

    Forbes

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    Neat solution, I like it. Surely if your return pump was big enough, you could still branch off and achieve the same results but with one less pump.
     
    Last edited: 2 Dec 2016 at 12:22
  20. dubediver

    dubediver

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    Forbes, sure that would work providing your flow back to your tank does not drop too low.
     
  21. dubediver

    dubediver

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    So higher flow over dsb is better ? To what degree can you increase the flow ?

    How does flow rate affect sediment ?

    Adding more aragonite to my dsb today, try to get al least 18cm

    should light cycle in dsb mimic tank, or more beneficial to run 24hours or inverse to tank. ( of inverse how dark does it need to be during the day ? ) I have some macro algae in my dsb compartment.
     
    Last edited: 2 Dec 2016 at 14:18
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