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Thread: "DE has built up and 'bridged' grids in filter."

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    "DE has built up and 'bridged' grids in filter."

    Can someone explain what this means exactly? I am three days post opening and still trying to get my water right, but one thing is consistent from last year. I continue to have a slightly milky or cloudy look to my water. It isn't the crystal clear water I used to have in the past.

    I am presently trying to decide whether it is a hardware issue or a chemical issue and found this link which mentions DE building up and bridging grids?
    10,000 gallon
    Viking Freeform Fiberglass Inground Pool. FNS Plus DE Filter Pentair Challenger .75hp pump

    NC KANSAS44

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    Mod Squad Bama Rambler's Avatar
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    Re: "DE has built up and 'bridged' grids in filter."

    If you suspect it's bridged then you should tear it down and inspect it to see for sure.

    Also post a full set of test results so we can see if it's a balance issue or something else.
    Dave J. TFP Moderator
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    Melt In The Sun's Avatar
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    Re: "DE has built up and 'bridged' grids in filter."

    Given the other issues you've been having, I'd say don't worry about it just yet. Like Bama said, there's nothing wrong with opening it up and cleaning it out to be sure, but I'd keep up those partial drains for CYA before you worry about your equipment
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    Re: "DE has built up and 'bridged' grids in filter."

    Quote Originally Posted by Melt In The Sun
    Given the other issues you've been having, I'd say don't worry about it just yet. Like Bama said, there's nothing wrong with opening it up and cleaning it out to be sure, but I'd keep up those partial drains for CYA before you worry about your equipment
    I just cleaned it last week prior to opening. I am just curious what they mean by bridging the grids? I always have de caked between my grids at the end of the year.

    These were my test results from yesterday. As mentioned in other posts, I am planning to attempt a partial drain once my cya reagent arrives so I can test.

    FC 48
    CC 0
    TC 48
    pH 7.5
    TA 230
    CYA 100 +

    Additionally, after further examination, it seems like the term cloudy doesn't really describe my water. In full sun it has more of an "oily" appearance like perhaps baby oil. Don't misunderstand, I am not saying it looks like there is oil in my water.

    It's just that the water is a bit opaque rather than crystal clear. I keep thinking baby oil when I look at it.
    10,000 gallon
    Viking Freeform Fiberglass Inground Pool. FNS Plus DE Filter Pentair Challenger .75hp pump

    NC KANSAS44

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    maxepr1's Avatar
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    Re: "DE has built up and 'bridged' grids in filter."

    Thinkly, my filter is "Bridged" every time I break it down and clean it. I really don't know how to prevent it but it hasn't had an effect on my water clarity. I have an FNS 60 and if I follow there recommendations for charging after breakdown( 12 1lb. coffee cans full of DE) the bottom 12" of the grids are "Bridged"! So I have been backing off the amount I put in and it does lessen the "Bridging" but it doesn't stop it. Also make sure your vent/breather at the top inside your tank is not blocked. Not sure what filter you have but FNS's have a vent at the top, if it gets clogged it will put DE back into the pool. Your FC is high are you doing a open up shock?
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  6. Back To Top    #6

    Re: "DE has built up and 'bridged' grids in filter."

    Quote Originally Posted by maxepr1
    Thinkly, my filter is "Bridged" every time I break it down and clean it. I really don't know how to prevent it but it hasn't had an effect on my water clarity. I have an FNS 60 and if I follow there recommendations for charging after breakdown( 12 1lb. coffee cans full of DE) the bottom 12" of the grids are "Bridged"! So I have been backing off the amount I put in and it does lessen the "Bridging" but it doesn't stop it. Also make sure your vent/breather at the top inside your tank is not blocked. Not sure what filter you have but FNS's have a vent at the top, if it gets clogged it will put DE back into the pool. Your FC is high are you doing a open up shock?
    I have an FNS Plus 36 sq. ft. and yes I have the vent/breather. I do not believe I am putting any DE in the pool as I have done the sock test on the returns and the returned water seems clear. I have high FC because yes I just opened.

    My current plan is to to some major drain/refills as soon as time allows to try and make a dent in my cya.
    10,000 gallon
    Viking Freeform Fiberglass Inground Pool. FNS Plus DE Filter Pentair Challenger .75hp pump

    NC KANSAS44

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    maxepr1's Avatar
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    Re: "DE has built up and 'bridged' grids in filter."

    Thinkly, has it ever been clear? What are you putting into the water besides bleach right now?
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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