Cycling a 3000L plus tank

Discussion in 'Pumps and Waterflow' started by FDB, 7 Dec 2009.

  1. FDB

    FDB

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    Hi guys.
    Apparently to cycle a 3000L plus tank, i need a 30000L per hour pump.
    That is all fine and well, but geez.
    Would i split that flow so half of it goes to the sump/skimmer and the other is just looping back to the tank?
    Or does it mean that i have to cycle 30000L per hour though my filters and skimmers on a 3000L tank?
     
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  3. viper357

    viper357 Admin MASA Contributor

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    30 000 lph pump....wow, I don't think the titanic had bilge pumps that big :p

    I think you may be confusing yourself with the required amount of turnover in the display tank, get a few pumps for waterflow in the main display tank then use (perhaps an OR3500?) to run from your sump back to the main tank, split into 2 or 3 outlets into the display tank. You don't want 30000lph running through your sump, your sump must have relatively gentle flow running through it.
     
  4. Bob the (reef)builder

    Bob the (reef)builder

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    Yup an OR3500 or OR6500 will do the trick. You going to need a pretty huge sump and skimmer to deal with 30 000l .;)
     
  5. FDB

    FDB Thread Starter

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    Ah ok.
    I can relax then.
    So i don't have to push the 30 000Lph through the skimmer and filter. I just have to have that kind of flow in the tank...
    Now.
    Based on the 3000L tank, how much lph must u push through filtration?
     
  6. viper357

    viper357 Admin MASA Contributor

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    If you are going to have a normal display tank with a sump underneath it then I would go with an OR3500 (Aqua Medic Ocean Runner 3500 lph) pump, or if you want to split the returns to 3 or 4 outlets then go with the bigger OR6500, I have an OR6500 running from my sump into my 8ft tank, it is split into 3 returns and it's a fairly decent amount of flow coming out, although perhaps a bit too much flow for the sump, but I don't have a DSB in my sump.
     
  7. RiaanP

    RiaanP Moderator

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    Flow accross the DSB should be slow enough not to blow the sand away, but fast enough not to be stagnant. Recommendation is somewhere between 3 to 5 times your total water volume turnover per hour. But this obviously is not a golden rule. It depends on the DSB width (not the length). A 300mm wide DSB cannot handle the same water flow than a 600mm wide or even wider. So it depends on the setup.

    I believe that the same calculation used to determine the overflow box width can help you in this calculation. have to find that link.:(
     
  8. RiaanP

    RiaanP Moderator

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    the link was easy to find...

    Check in this thread,
    Calculating overflow width - Pumps and Waterflow
    or directly
    Drain/Overflow Size

    the partition between the DSB and return chamber works basically just like the overflow box in the tank. Just not sure if it is correct to calculate the flowrate the same

    So a 1500 Gallon per hour = 6813 L/h
    needs an overflow width of 23 inches = 584mm

    But I think almost 7000L/h over 600mm wide DSB will be too much.
     
  9. FDB

    FDB Thread Starter

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    3 times total volume = 3x3000 = 9000L per hour through my filtering system.
    That means a 50mm drain pipe diameter and a 1M linear overflow size (i assume the width)..
    I cannot push 9000Lph over a DSB. But i can make my whole tank's floor 20cm deep no problem. (How many years before a dsb crash.. what then?) :)

    My worry is skimmer and the plants like cheato..
    I can run pipes outside, install a 500L Refrigium that can also maybe house my skimmer, and put a seethrough canopy over it to keep dust and leaves out. The cheato will then grow in sunlight. In the canopy, i can install fans for cooling...

    So i will have the tank thing, with 20cm deep sandbed as floor stacked with live rock. Diffused natural light for lighting, water overflowing to the 500L refrigium that is in the canopy whatnot with the skimmer, and a pump pumping 30000Lph in a split system (lets say 6000Lph through the refrigium) and teh remaining 24000Lph closed back to the tank's various inlets. (Or two pumps for redundancy)

    Me thinks this thing is going to overheat....
    I can run the water through a radiator........... Hmmmm. (The plastic ones you get for cars)
     
  10. RiaanP

    RiaanP Moderator

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    Just remember an in display tank DSB got its own set of problems.

    Sandstorms, especially with over 40 times water volume pumps blowing it all over. You will be surprised what happens if one pumps is adjusted into another angle. Next night the sand shifted to form another sand dune at another place in the tank.

    Also beneficial critters in the sand should be "protected" from crabs, gobies, sea stars, cucumbers and snails that will predate on them. So having them all together in main display gives you a limit on life stock options. Even your humble hermit crab will eat what you want to encourage to strive in the sand.

    That is why a remote DSB is better.

    Yes 9000L/h over a DSB? now that will be a sandstorm in the making. This you need to test beforehand, but I believe a 600mm wide dsb with around 4-5000l/h return pump should be ok.

    Rules changes or are adjusted the bigger you go.
     
  11. FDB

    FDB Thread Starter

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    Ah man!
    Ok wait.
    Aerobic goggas would be all over the tank right?
    the DSB kicks but because it allows the anerobic gogaas to live.
    So.
    If i limit my Hermits, add snails and selectively put fish in (I'm thinking bigger spiecies rather than smaller.. you know.. those that most tanks are too small for..) The small organisms should be ok?

    I guess what i'm saying is....
    If i want an in-tank DSB... Can i solve the in-tank DSB issues by carefully selecting inhabitants? (i mean one shark/Moray/whatever in the tank and two hermits should not impact the DSB negatively for example)

    Then. From the floor (Sand) to the top of the tank is about 1.2 to 1.5M
    So it should be easy to make sure the water movement on the sand is limited?
     
  12. RiaanP

    RiaanP Moderator

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    Check out this link, posted today on some other thread on LR vs DSB by Adee.

    Article by Anthony Calfo, makes interesting reading and justify remote DSB vs in tank DSB
    DSB article - CALFO
     
  13. RiaanP

    RiaanP Moderator

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    And your proposed set-up is almost mangrove set-up. Big water in tank turnover and water flow is not that important. I doubt that more than 10 times will be needed. That again will create other issues, like detritus settlement. There for a clean-up crew will be vital. You have to be very careful in your inhabitant selection.

    This will be a very interesting but challenging set-up to get it right.

    Unless I misunderstood, and you will not have plants standing in the water. Then it is more like a rock pool. That could work.
     
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