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Thread: DE filter - spewing DE, and clogging??

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    DE filter - spewing DE, and clogging??

    I think I know whats wrong... But I'm hoping maybe there is a good way to confirm it before I have to go off and spend all kinds of money... Or ideally I'll be just wrong, which would be awesome!

    I have a Pentair NS48 stainless steel DE filter, its probably at least 20 years old... But I don't actually know (manual revision date was 4/1/91).

    I had an algae outbreak, so after knocking that problem out, my pressure had risen. I backwashed, pressure was still high, so I went for the manual cleaning. I should also note that we have a pool jet about a foot above the pool, and I usually use how far that sprays as kind of a side indicator something is off....

    So, I take them apart, clean them per manufacturer instructions, and re-assemble the grids, which each time I do it reminds me that I'm terrible at jigsaw puzzles. I did a chemical cleaning 5 or 6 months ago as well, so these things should be nice and clean. I go to recharge the filter, and my water goes from clear to "where did the bottom go??". I waited a week, it cleared up, until I went to sweep it, then I found all that DE. Frustrated, I took the filter apart, and looked for tears (I have had to replace 2 of the "fingers" already), but I couldn't find anything that looked obviously wrong. So I started with replacing cheap parts. New O-Ring on the standpipe, and a new "mesh" filter on top of the manifold (I think I saw a thread somewhere on here where that was an issue). When I cleaned the filters, there was at least some DE on the grids, but I don't think it had enough....

    I start re-charging the filter, and it looks like DE is just coming straight out without stopping. So I went and grabbed some of my wife's stockings (which I think was recommeneded in another thread) to catch what was coming out just to verify, and it was mostly DE (and some larger dirt particles... which sort of surprised me). This was on Sunday. It was hot, late, so I let it run all week. Things again, cleared up, until I just went out and swept. And there was all the DE. I also see it coming out when I turn the pump off, then on.

    So, I'm at the point, I strongly suspect I have a torn grid, but I don't know which one.... There are 6 that I haven't replaced... And I was hoping not to have to do them all... Does anyone have a way to checking/testing a grid for leaks? DOes this seem like the problem? Should I just break down and replace the other 6? Any help would be greatly appreciated.
    17k gal, plaster, Pentair DE Filter (48sf), 2hp hayward pump

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    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: DE filter - spewing DE, and clogging??

    Sounds like a torn grid to me. Since you've already replaced two, and you're looking at replacing a third or maybe a fourth, why not just bite the bullet and replace them all now?

    One afterthought... you don't have a multiport valve that's set on recirculate, do you?
    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!

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    Re: DE filter - spewing DE, and clogging??

    No - I have the up/down slide kind that either goes into the pool, or into the drain.

    On a side thought, does my "elevated" jet (about a foot above the pool, built into the wall) getting less and less flow throughout the day indiciative of anything? It starts out maybe going 6 inches horizontally into the pool, and in a few hours, it barely comes out at a trickle... Does it sound like something else could be wrong as well, while I have the stupid thing taken apart again, or something else I should look for?

    *sigh* There goes my afternoon tomorrow
    17k gal, plaster, Pentair DE Filter (48sf), 2hp hayward pump

  4. Back To Top    #4

    Re: DE filter - spewing DE, and clogging??

    Your slide valve might be bad. You can take it apart to check it.

    The best way to find a rip in a grid is to take it out, clean it thoroughly with a hose, and carefully inspect it for damage. Any damage should be noticeable.
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    Re: DE filter - spewing DE, and clogging??

    Thought I'd throw in an update.

    I spent this afternoon sweating profusely and taking far too many trips between the pool store and home depot.... I replaced the stupid grids, and all the other broken parts (like the clamp...), and added new DE, and miraculously, my pool did not turn to milk ! And my elevated jet is spraying water like a champ.

    I couldn't find anything obviously wrong with the old filters... They had yellowed... And were a little frayed... Some of the plastic clamps seemed a little weak, but no big tears (I've had a couple with very obvious tears....), but replacing all of them seemed to fix it, so torn grid was right on! Thanks!!! Water looks crystal clear now
    17k gal, plaster, Pentair DE Filter (48sf), 2hp hayward pump

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