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Thread: DE does not coat filter grids

  1. Back To Top    #1

    DE does not coat filter grids

    Hi,

    I am in Maryland. I am struggling to understand an issue with my filter that I started to have near the end of last swim season. The issue is that D.E. powder does not stick to my filter grids! I opened my pool last week and I have started from scratch twice using D.E. from two different manufacturers, first with a product bought from Leslies and then a product brought from WaterCrafsters. No difference. When I opened the filter tank I still see no coating on the grids.

    Then today I noticed one thing. After the pump stops, white powdery water comes back to the pump (I can see it through the clear window) and goes slowly all the way back to the skimmer (I only have one skimmer). I don't remember I saw this when I had no problem with the pool. I don't know if these two are related.

    I asked Leslie's and a local pool service store WaterCrafters and they didn't seem to know why DE wounld not stick to the grids either.

    I don't want to run the filter without the grids properly coated with DE.

    Anyone knows what is going on here? I am starting to get frustrated.

    Any help is greatly appreciated.

    John

  2. Back To Top    #2
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: DE does not coat filter grids

    DE falling off the grids isn't so bizarre, but it shouldn't be flowing backwards.

    I'd look for a lot of air trapped in the filter (that's why there's an air bleed on top) and then see if the check valve is stuck - or was never installed.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  3. Back To Top    #3

    Re: DE does not coat filter grids

    Richard320,

    Thanks for your quick reply.

    I also thought of air inside the filter tank. What I did to ensure that air is out is that I opened the relief valve on top of the filter until water comes out. I also can tell there is no more air inside the filter by gently tapping the top - you can tell the difference when there is no air.

    What I understand is that after fresh DE is added, it would coat the grids within half hour or so. Once the grids are coated the DE will stay on them unless it is hosed off. I left the pump run over night twice and i still not see D.E. coating.

    The O-ring may be a problem. When the pump is running there are tiny drops of water dripping out - like a drop a second or or so. When the pump stops for hours, I can tell lot of air gets inside the tank. It could be a problem. But this still does not explain why DE would not stick to the grids.

    Any help is greatly appreciated.

    John

  4. Back To Top    #4

    Join Date
    Mar 2007
    Location
    Coastalish 'down easter'
    Posts
    4,160

    Re: DE does not coat filter grids

    Welcome to TFP!!

    Have you read teh 'Use and Care for DE filters" in the Further Reading section of Pool School?
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  5. Back To Top    #5

    Re: DE does not coat filter grids

    I did not see it. I just signed up today. Thanks a lot for pointing me over there. I read the article. Based on the article I might have missed one thing: I added DE before I made sure no air was in the tank. I will do it all over again. Thanks. I will report back to see how it goes.

    Thanks again.

    john

  6. Back To Top    #6

    Join Date
    Dec 2010
    Location
    San Diego, CA
    Posts
    1,129

    Re: DE does not coat filter grids

    Do you have a variable or two speed pump? Are you running on low speed with your pump? You need to run a high speed for 20 mins or so when you first add the DE to make sure it coats the grids. What model filter do you have?
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

  7. Back To Top    #7

    Re: DE does not coat filter grids

    I am pretty sure my pump has only one speed. I am not quite sure what model my filter is. I bought the house two years ago with the pool. What I can tell is the pool was built by Blue Havens and all equipment appear to have "Blue Havens" on it.

    By the way, after I read the article recommended by Ted from Luv&Luk I cleaned up the filter and started from scratch again. I have the filter a couple of hours but I have not opened the filter tank yet so I don't know if the filters grids were coated properly. I will you all how it went when I open the filer.

    Thanks for your response.

  8. Back To Top    #8

    Re: DE does not coat filter grids

    Well,

    I have no air leaks, run my two speed 1.5 hp pump on high for about ten minutes when adding new DE, and Lowtherafter, and never see any DE on the bottom 2/3 of the grids when I clean it once a month, but quite a bit sitting at the bottom of the filter. I always assumed the clean DE falls, and this was normal.
    24' AG Doughboy w/ 5'8 dish bottom, CWII DE Filter, 1.5 hayward 2 speed pump, Aquatrol SWG.

  9. Back To Top    #9

    Join Date
    Dec 2010
    Location
    San Diego, CA
    Posts
    1,129

    Re: DE does not coat filter grids

    I imagine a good bit will fall when you pop the filter off. The fiber clear stuff falls every time - thats something that turned me away from it as I don't see my pump on low speed stirring that stuff up enough to properly coat the grids (cartridges in my case). But that seems weird to be happening with DE. How old are your screens? Have you acid washed them without doing the tsp treatment first? Stuff like this makes me wish all filters had a view strip like the one in the fiber clear video lol
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

  10. Back To Top    #10

    Re: DE does not coat filter grids

    My grids have about 2 months on them--brand new.
    24' AG Doughboy w/ 5'8 dish bottom, CWII DE Filter, 1.5 hayward 2 speed pump, Aquatrol SWG.

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