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Required Bell Siphon size

Discussion in 'Commercial & Small AP Farm Information.' started by srujan, Feb 9, 2017.

  1. srujan

    srujan New Member

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    India
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    Telangana
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    Hyderabad
    Hi Team,

    I am planning on constructing a 20ft × 4ft gravel growbed with a bell siphon in it. I need help in identifying the right sizes of PVC pipes i can use to make this and also the placement of the bellsiphon in the growbed. I have searched internet and couldnt find relavant information abt this topic for the beds of this and higher sizes.
    Please let me know if any more information is needed from my side.

    Thanks,
    Srujan.

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  2. Robert123

    Robert123 Active Member

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    I'll be interested in seeing the responses you get here as well as we are expanding this year, but have not built beds this size. Gut instinct tells me that a 20 ft bed length might be the practicle upper limit, but this also depends on the media you are going to use. 3/4" gravel or hydroton is perhaps OK, but smaller gravel (chat) perhaps not. Again - just gut instinct - I'd probably use a 1" diameter stand pipe inside the bell siphon. You'll need plenty of flow area into the bell to feed the standpipe as well.
     
  3. srujan

    srujan New Member

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    Hi Robert,

    I have seen lot of implemetaions done in my area which are of this size (20ft × 4ft), so i beleve it is okay with this size.
    Yes, i am plannimg to use 3/4" gravel. As you said, i dont think 1" stand pipe will support this size of growbed as it may take bigger size of standpipe to drain around 700 litres (30% of growbed volume)+ in 15 mins if i want to have 4 cycles to turn over my 2600 litres fish tank every hour, but let experts comment on this.

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  4. srujan

    srujan New Member

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    Any help here pls....

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  5. Yabbies4me

    Yabbies4me Administrator Staff Member

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    .
    I have a customer with a very similar sized GB (600 x 100 x 20cm). A 25mm standpipe provided about 45 minute F&D cycles when the water flow was tuned to suit.

    We changed the standpipe to 32mm, which reduced the cycles times substantially. I can't remember what the new times were exactly, but it was still nowhere near 15 minutes. I seem to recall we got it down to around 30 minutes, but can't say for sure, it was 3 or 4 years back now. I know one thing for certain though, we both agreed that we probably should've gone 40mm, but he stuck with the 32mm.

    You GB is probably slightly larger, so I would suggest going with a 40mm standpipe. That would require a bell made from 90mm or even 100mm pipe.

    The water inlets into the bell should be near, but not at the base of the bell, and they should be sufficient enough to not hinder the full flow of the 40mm pipe when the siphon initiates. The outer gravel guard should also have sufficient slots to allow full flow.
    .
     
    srujan and omero.combi like this.
  6. srujan

    srujan New Member

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    Thanks Yabbies for the suggestion. Will try this and update here.

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  7. Ringer

    Ringer Active Member

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    Hi srujan,
    Cylcle times are firstly determined by your fill rate no matter what size piping you use . You need to quantify that variable first before calculating pipe diameters and the resulting cycle times .Or adversely choose a desirable cycle rate and then select your pump based on that flow rate and then your stand pipes diameter accordingly. Keeping in mind you ideally want to cycle all of the water in your system around once an hour if you want to maintain healthy water with a high fish stocking density.
    Cheers
    Hope that helps.
     
    Last edited: Mar 6, 2017

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