Help with plumbing a DIY

Discussion in 'Anything DIY Related' started by erratiC, 16 Jul 2013.

  1. erratiC

    erratiC

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    Hey guys,

    I'm trying to design a primarily SPS-dominated cube and am needing a bit of advice, please.

    My cube's dimensions are 510 x 570 x 580 (h) with a water level at 550 so 160 litres. Height from Return pump into the DT is at 1.5m. Sump volume is 65 litres so total volume is 225 litres.

    I've got a Syncra Silent 5.0 pump that I'm wanting to use as my return pump - it is rated at 5000l/h.

    Ok so, first, how do you decide on what literage/hour return pump is sufficient?
    Second, Will my return pump be decent enough?
    Third, before i go purchase any DT glass/piping and get gluing, is my plumbing decent in the pic included?
    Fourth, I was thinking 50mm from DT to sump and 32mm from Return pump split at the end into the DT like in the pic. Is this ok?

    If i think of anything else, i'll add to the list... :blush:

    Thanks.

    [​IMG]
     
    Last edited: 16 Jul 2013
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  3. 459b

    459b Moderator MASA Contributor

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    I'd try lessen the kinks in the return pipe. 90 degree bends will limit flow so the less the better. Bends from the overflow wont be an issue as its gravity fed.
    What's the head height of the pump? Will need to check how much it can push at that height.
    Pipe sizes sound fine.
     
  4. erratiC

    erratiC Thread Starter

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    Thanks @459b, there are actually 2 bends but they aren't showing in the pic that well.

    I've had a look at graphs for that Syncra Silent 5 and it looks like at 1.5m height it pushes around 4000l/h. Would that be still be enough?

    [​IMG]
     
    Last edited by a moderator: 26 Nov 2015
  5. RiaanP

    RiaanP Moderator

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    After head height and back pressure due to elbows, you end up with about 4000L/h delivered into the display. Divided by 2 and you get 2000L/h flow per outlet.
    That would give your display a turnover of only 12.5
    For SPS you need 40 to 60 times turnover.
    You will need internal powerheads to provide additional flow.
     
  6. erratiC

    erratiC Thread Starter

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    Hey Riaan, I understand that I will definitely be needing additional flow in the DT, thanks.

    I'm just trying to figure out that by having a 50mm pipe running from the DT to the sump moving the water at x l/h - how does one figure that the return pump will be able to keep up with the rate coming from the DT using the 32mm return pipes I have?

    If the rate at which the water is coming from the DT is more than what the return pump can deliver then surely the sump will overflow?
     
  7. 459b

    459b Moderator MASA Contributor

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    Pump will be fine. I doubt it will cause the sump to overflow. You need to run the sump with some empty space so that the excess water has a place to go when you switch off the return pump.
     
  8. ScottK

    ScottK

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    If your overflown is setup correctly the water coming from the DT can never exceed the rate of the return.

    I run 50mm on my overflow and 25mm splitting to two 20mm's on my return.
     
  9. erratiC

    erratiC Thread Starter

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    @ScottK, any chance you've got a pic if your plumbing? Do you have a thread somewhere? I'd look but I'm on Tapatalk atm.
     
    Last edited by a moderator: 26 Nov 2015
  10. Fred d

    Fred d

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    remember bud your flow from the dt to the sump stops when the waterlevel drops lower than return chamber ... thus ... every litre pumped into the dt will end up as the potential of volume that can possibly return to the sump ... thus ... the rate of flowthrough in your dt is determined by your return pump (keeping in mind the loss of flow due to headhight and restrictions with bends) I have 1 x 40mm return pipe from my dt to my sump and 1 x 16mm line from my sump to my dt and it works perfectly ...

    the volume of water in your dt between your return chamber and your feed ports will be the volume you need to leave space for in your sump as it will be the point to wish the the water will drop when the pump stops ...

    personally I would put a 30 degree bend on the 2 feedports into the dt to have the water flow into the watercolumn instead of splashing onto the top of the water surface . also look at some sort of durso setup in your return pipe to get things nice and quiet ....

    hope this helps
     
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  11. Fred d

    Fred d

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  12. dallasg

    dallasg Moderator MASA Contributor

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    hi
    if i may add some advice, on the pipe going to the second return, you will need to add a valve so that you can adjust the flow to force water through the first opening which the flow will naturally bypass, by limiting the flow to the second outlet it will force it through the first.
    as for the return pump thats fine, wont be an issue.

    in my opinion the water flow rate through the tank and sump is irrelevant, as long as you have super flow in the DT then that is perfect. a return pump shouldnt be used to create flow but return water. with todays new technologies there is no need to have specific flow unless you run a dsb,

    keep it simple and things will be perfect
    here is a nice small effective sump

    product.jpg

    IMG_5902.jpg

    IMG_5898.jpg
     
  13. ScottK

    ScottK

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    I'll try take some pic's this evening but as @dallasg says it's best to keep it simple.
     
    Last edited by a moderator: 26 Nov 2015
  14. RiaanP

    RiaanP Moderator

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    Actually its the other way around. The overflow needs to be able to cope with the water pumped into the display by return pump.

    Not the return pump needs to be able to cope with the volume of water coming down the overflow.

    On less powerfull pumps, that rate down the overflow, and up the return is equal. The overflow can only let out 2000L per hour, if 2000L per hour enters the system. If less enters, it can only let out what came in.

    But on too strong return pumps, with too small overflow wall, you can end up with an increased head height in the display. Even until the water touches the braces or even overflows. Same will happen if there are suddenly a restriction in the down pipe, like a snail or fish caught in the ball valve restricting the flow on the downpipe. Had a Blue Green Chromis do that to me one time, flooded my display. Best is, after I opened the ballvalve the fish actually survived all the way to the sump. that is why I do not like restriction on overflow, and therefor slimline overflows as they depend on ballvalves to silenced them.

    Anyway, a 50mm PVC pipe with smoothed down edges can handle up to 6000L/h under gravity feed. So you can easily push 6000L/h into the display, the entrance to the PVC pipe can take up to 6000L/h.
    The problem is your overflow. The total linear length must be sufficient to ensure a low head height. No point in having a 10mm or more head height in your display, flushing fish over into the overflow. Using combs will restrict the flow and increased the head height even more. There is a formula for that, but to explain in simple terms, a 50mm wide overflow with a water depth of 50mm will allow 3000L/h. A 100mm wide overflow for same rating will have a water weir head of 28mm. 150mm wide and the weir head drops to 21mm

    For a flow rate of 3000L/h and a weir head of 5mm, your overflow needs to be 1250mm wide.

    Take into account that the weir head, is the water that will go down extra to the sump in case of a power failure.
    On your tank of 510 by 570 footprint and 5mm head that is 1.45L water. 10mm weir head and your return chamber needs to be able to hold 2.9L extra.
     
  15. RiaanP

    RiaanP Moderator

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    On your tank, if 570 is the width, and you want a weir head height in display of 5mm, then you are looking at 1400L/h entering the display. I think your return pump is too strong.
     
  16. erratiC

    erratiC Thread Starter

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    Thank you, @dallasg, @Fred d, @459b.

    @RiaanP, what you've just said is exactly what I was looking for - hard info on how it all works - for me to design something, it really does help knowing all the facts that go with it.

    I plan on adding a gate-valve to the 50mm coming from the overflow with a union(I think it's called that?) on one end for easy removal and to "dial in" the sound coming from the skinny overflow.

    My skinny overflow has a width of 458mm with a depth of 30mm. How do you work out the vol./hour going over it? If my return pump is in fact too strong I'll have to add a t-piece with a valve after it to the return pipe. That t-piece could either be ended with a tap or lead back to the skimmer chamber.
     
    Last edited by a moderator: 26 Nov 2015
  17. dallasg

    dallasg Moderator MASA Contributor

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    here is my skinny overflow, return was 5000L and drains were 32mm x 2
    overflow was 400 long x10 gap x 100 deep

    [​IMG]
     
  18. RiaanP

    RiaanP Moderator

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    here is the formula
    Q = 1.84(L – 0.2H)H**(3/2)

    The depth of the overflow does not matter really, as long as the bulkheads are hidden.

    The gap width should be more than the weir head height. So 10mm is good.

    On 458mm wide, with 10mm weir head, it works out to about 3100L/h that will go over.

    Weir head is the depth of the water as measured between the overflow glass and actual water depth. That few millimetres.
     
  19. RiaanP

    RiaanP Moderator

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    Q is the water flow rate in m3/sec,
    L is the length of the weir in metre
    H is the head over the weir in metre
     
  20. RiaanP

    RiaanP Moderator

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    It is the calculation used to calculate the water released by an overflowing dam. The dam wall width is known. The weir height is measured. And the volume released calculated.
     
  21. erratiC

    erratiC Thread Starter

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    Thanks @RiaanP. Having a look at the following website goes into detail as well, it's good to understand how it all fits together :

    Stream Gaging Using the Velocity-Area Method

    @dallasg, how did you decide on those measurements when you designed that overflow? Are you using 2x 32mm pipes for failover against using a single 50mm?
     
    Last edited by a moderator: 26 Nov 2015
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