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Thread: Pump too big for filter?

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    Join Date
    Jul 2013
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    Pump too big for filter?

    I've always had a problem with dirt blowing back in the pool when vacuuming. Essentially the filter never clogs, it just blows dirt right through.

    The filter is a Waterway Plastics - Clearwater high rate sand filter 22" rated for 55gpm max.

    The pump is a Hayward SP1580X15 which says 70gpm on the tag.

    Am I on the right track here? I'm thinking that a smaller pump might actually work better in that the filter will actually plug up when it's dirty.

    Or, can I just close the valve on the intake to slow the flow down a little?
    18K gal 28ft round AGP, Hayward Power-Flo LX 1.5HP pump, 22" diameter round Sand filter 150lbs

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    Re: Pump too big for filter?

    I had the same problem and put a smaller pump in
    Pumps should be matched to filter


    10,000 gallons inground Leisure fibreglass pool, Hayward powerline pump, Quality120 glass media filter, 27kw output air source heat pump and thermal cover.
    Retractable cover with Polycarbonate roof and glass side for all year round use. K-2006C test kit and Speed stir

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    Re: Pump too big for filter?

    You could also try adding some DE through the skimmer to raise the pressure a bit and see how it goes first


    10,000 gallons inground Leisure fibreglass pool, Hayward powerline pump, Quality120 glass media filter, 27kw output air source heat pump and thermal cover.
    Retractable cover with Polycarbonate roof and glass side for all year round use. K-2006C test kit and Speed stir

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    CJadamec's Avatar
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    Re: Pump too big for filter?

    I wouldnt add DE to your filter until you get the filter sorted out. If you are getting fine silt back when you vacuum but no sand it's possible the sand bed has channels in it from the high flow rates. If you are getting sand back as well then you might have damaged laterals. I would first try deep cleaning your filter which should fix any channeling for a while.

    If you are looking to change your pump flow you can get a 2-speed motor for your pump and run the pump on low speed for everything but vacuuming. It will lower your electricity cost considerably and make you filter happier. Don't use valves to alter the flow rates in and out of your pump.
    Chuck-
    15x30 AG, Pentair Superflo VS, 19" sand filter, TF-100 test kit
    Aqua Comfort ACT750 heat pump / 6x20 ground mount solar panel / DIY automation

    Photos of 2016 Build, Inside Your Breaker Panel, Free Copy of 2017 NEC code
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  5. Back To Top    #5

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    Re: Pump too big for filter?

    This is what I have tried so far:
    • deep cleaned the filter, twice
    • disassembled the filter, dumped the sand, examined the laterals for cracks, replaced the sand
    • replaced the spider gasket

    I just checked the pump specs on Hayward's website. The SP1580X15 is rated for 91gpm! (depending on head pressure) That seems ridiculously high for the filter I have.

    Is the 22" filter appropriate for the pool? Any reason to consider replacing it?
    18K gal 28ft round AGP, Hayward Power-Flo LX 1.5HP pump, 22" diameter round Sand filter 150lbs

  6. Back To Top    #6
    CJadamec's Avatar
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    Re: Pump too big for filter?

    A 22 inch sand filter is fine for your pool, you can always go bigger with sand but the one you have is fine. By the sounds of it your current pump is pushing way more water than your filter can handle. What kind of filter pressures were you running.

    If all you have in your system is a pump and a filter with no heaters or solar panels you would be fine with a 3/4hp pump. So you can either change out your motor with a 2-speed model which is probably your cheapest option or you can buy a whole new pump.

    I would recommend a 2-speed pump no matter which way you go because it will save you a lot on the electric bill. You should also look to see if your power company offers rebates for switching to an energy efficient pump.
    Chuck-
    15x30 AG, Pentair Superflo VS, 19" sand filter, TF-100 test kit
    Aqua Comfort ACT750 heat pump / 6x20 ground mount solar panel / DIY automation

    Photos of 2016 Build, Inside Your Breaker Panel, Free Copy of 2017 NEC code
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  7. Back To Top    #7

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    Re: Pump too big for filter?

    We have a heater that came with the pool but I've never hooked it up. Filter problems have kept me distracted.

    Is a 1hp 2-speed pump appropriate considering we might want to use the heater some day?
    18K gal 28ft round AGP, Hayward Power-Flo LX 1.5HP pump, 22" diameter round Sand filter 150lbs

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    CJadamec's Avatar
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    Re: Pump too big for filter?

    Even with a heater a 1 hp pump will be plenty. Assuming your pump and filter are right next to your pool you should have very little plumbing head on your pump. Your electric bill will be much nicer running that pump on low speed.
    Chuck-
    15x30 AG, Pentair Superflo VS, 19" sand filter, TF-100 test kit
    Aqua Comfort ACT750 heat pump / 6x20 ground mount solar panel / DIY automation

    Photos of 2016 Build, Inside Your Breaker Panel, Free Copy of 2017 NEC code
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  9. Back To Top    #9

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    Re: Pump too big for filter?

    If I put a smaller hp pump on the same impeller assembly, will the motor just run slower (at full speed) to give me less flow through the filter? Does the resistance slow down the new pump, or will it run at full speed and still give me the same flow, which is too fast.

    Just want to make sure I understand this before I start spending money.
    18K gal 28ft round AGP, Hayward Power-Flo LX 1.5HP pump, 22" diameter round Sand filter 150lbs

  10. Back To Top    #10
    CJadamec's Avatar
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    Re: Pump too big for filter?

    If you put a smaller motor on your current impeller you will burn out the motor. Single speed motors are just that. If you want to keep your current wet end and just replace the motor get a 1.5hp 2 speed motor for your pump. That motor can be found HERE.

    Alternatively since the new motor is just as expensive as a whole new pump a good selection can be found HERE. Either a 3/4hp single speed or a 1hp dual speed should be plenty of pump and not kill your filter.
    Chuck-
    15x30 AG, Pentair Superflo VS, 19" sand filter, TF-100 test kit
    Aqua Comfort ACT750 heat pump / 6x20 ground mount solar panel / DIY automation

    Photos of 2016 Build, Inside Your Breaker Panel, Free Copy of 2017 NEC code
    TFP is AD Free and is funded solely by member support click here to help

  11. Back To Top    #11
    mas985's Avatar
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    Re: Pump too big for filter?

    What is the current filter pressure?

    You could just downsize the impeller.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  12. Back To Top    #12

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    Re: Pump too big for filter?

    Gauge is broken this year but if I remember correctly it ran around 16 or 18psi and never increased more than 2psi even when its dirty.
    18K gal 28ft round AGP, Hayward Power-Flo LX 1.5HP pump, 22" diameter round Sand filter 150lbs

  13. Back To Top    #13
    mas985's Avatar
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    Re: Pump too big for filter?

    My guess is that the flow rate is below 45 GPM.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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