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Thread: Design Flow Rate - Sand Filters

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    Design Flow Rate - Sand Filters

    Is there any problem with going under or over the design flow rate on sand filters? If it is ok to go under or over this flow rate, how high over or how far under can one go?
    16 x 38 inground pool, 20K gal, vinyl liner, 0.75 HP Hayward Superpump (SF 1.0, 115 V), Hayward Pro Serier Top Mount 24" sand filter (300lbs sand) with 62GPM design flow fate and 3.1 sq ft effective filtration area, Kreepy Krawly cleaner

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    duraleigh's Avatar
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    Re: Design Flow Rate - Sand Filters

    Not a good idea to exceed the flow rate but it is a VERY good idea to stay a little under it say by about 25% or so.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad Bama Rambler's Avatar
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    Re: Design Flow Rate - Sand Filters

    Going over the designed flow can channel the sand and cause debris to bypass the sand. Staying under it is great the more slowly the flow through the sand bed is the more debris gets caught.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Design Flow Rate - Sand Filters

    For backwashing, you need to achieve the minimum flow rate to get the sand clean.

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    Re: Design Flow Rate - Sand Filters

    How do I find out the minimum flow rate?
    16 x 38 inground pool, 20K gal, vinyl liner, 0.75 HP Hayward Superpump (SF 1.0, 115 V), Hayward Pro Serier Top Mount 24" sand filter (300lbs sand) with 62GPM design flow fate and 3.1 sq ft effective filtration area, Kreepy Krawly cleaner

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    Re: Design Flow Rate - Sand Filters

    Quote Originally Posted by jordangregory
    How do I find out the minimum flow rate?
    Backwash flow rates are typically between 75 to 100 % of the design flow rate, or between 15 and 20 GPM per square foot of sand surface area.

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    Re: Design Flow Rate - Sand Filters

    Thank you. That was very helpful. I almost feel good about opening my pool this season!!
    16 x 38 inground pool, 20K gal, vinyl liner, 0.75 HP Hayward Superpump (SF 1.0, 115 V), Hayward Pro Serier Top Mount 24" sand filter (300lbs sand) with 62GPM design flow fate and 3.1 sq ft effective filtration area, Kreepy Krawly cleaner

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