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Thread: Coating the grids of a DE filter with a variable speed pump

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    Coating the grids of a DE filter with a variable speed pump

    When coating the grids of a DE filter on a system with a variable speed pump, is there a particular pump speed which must be used? I thought I read a post somewhere on this board stating that the grids will not coat correctly at lower speeds. I am asking this because I stripped apart my one year old filter at the beginning of this season and completely cleaned the grids. I then re-coated the grids using the total amount of DE required for a new filter but I think that I did it at a pretty low speed. I mentioned in one of my other posts that I have been trying to vacuum out fine silt but it is coming back to the pool in the returns. I don't remember having this problem last summer when the pool was new and was wondering if I did not coat the grids correctly.

    So, what is the correct way to coat the grids using a VSP? Could this be the reason that the fine silt is not getting trapped in the filter?
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    mas985's Avatar
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    Re: Coating the grids of a DE filter with a variable speed pump

    You probably don't need to do it at fully speed but I would at least have about 15 PSI of filter pressure when you do coat the grids.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Coating the grids of a DE filter with a variable speed pump

    Could this be the reason that I can't vacuum up fine sand/silt without it returning back to the pool? From what I have read, a DE filter can filter to the 3-5 micron range. Shouldn't this be a high enough filtration rate to capture fine sand/silt?
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    mas985's Avatar
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    Re: Coating the grids of a DE filter with a variable speed pump

    Yes it should be able to filter that out so the problem could be that you have not coated the grids properly or perhaps not enough DE.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Coating the grids of a DE filter with a variable speed pump

    Actually, the most important thing when adding de is to have all the air bled out of the tank (de can't jump out of the water and pre coat dry grids). An increased pump speed will probably help with the pre coat. But not any faster than say 10-15 # on the filter.(like Mark said)
    Factory Warranty Station for:
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    Re: Coating the grids of a DE filter with a variable speed pump

    I called Jandy tech support today and spent approximately 80 minutes on hold (even though their message said a 20-25 minute wait) before giving up a leaving a voice mail. To my surprise, they called me back within a couple of hours. The support person that I spoke with said that the grids will coat properly at whatever speed you run the pump at. I believe the answers that I received from Mark and Pool Clown are correct and that the support person that I spoke with does not know the technical aspects of Jandy's products.

    I will probably open the filter up again this weeked and do a complete cleaning and then recoat the grids at a faster pump speed using the total amount of DE required for a new or clean filter. Thanks again for the help.
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    Re: Coating the grids of a DE filter with a variable speed pump

    Did you open the air bleed valve on top of the filter when you were refilling it with water?
    15ft round above ground pool (6600 gallons)
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    Re: Coating the grids of a DE filter with a variable speed pump

    Definitely depends on the design of the filter, but definitely make sure there is no air in the tank. A properly designed filter will coat the grids fine at any speed.
    In-ground Filters Engineer
    Pentair Water Pool and Spa, Inc.
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    Re: Coating the grids of a DE filter with a variable speed pump

    This weekend, I opened the filter and completely cleaned the grids using a garden hose with a nozzle. I then re-started the pump and made sure that all air was bled from the filter before re-coating the grids. Per earlier recommendations, I used a higher speed (3200 RPM) when re-coating the grids. I also left the pump running for the rest of the day at 3200RPM so that the DE would stick to the grid.

    I then tried brushing the silt towards the main drain but still can not remove it from the pool. I don't know if it's passing through the filter or if it gets suspended in the water (during brushing) and settles out when the pump is not running. I will try to use the vacuum head rather than brushing to prevent it from getting stirred up.
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    Re: Coating the grids of a DE filter with a variable speed pump

    Quote Originally Posted by poolneophyte
    ....I will try to use the vacuum head rather than brushing to prevent it from getting stirred up.
    Good plan.
    18k gal inground, everbrite finish, 505 sq ft; 1.5 hp two speed whisperflow; rheem 5100ti 100k btu heat pump; 3 sheer descent falls; DE filter; swg (cell out and using trichlor for now)

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