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Thread: DE Filter Woes...No D.E. in filter?

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    DE Filter Woes...No D.E. in filter?

    Hello all.

    When opening my pool last weekend, I added D.E. to my filter through the skimmer. However, I think that the D.E. ended up in my pool. The pressure on my filter is 4 psi and didn't rise at all when the D.E. was added, but the pool became cloudy. So I waited a little while then decided to backwash the filter, but the water was clear the whole time. Then, I decided to open up the filter and found no D.E. at all in it. I did a cursory inspection but didn't find any rips or tears on the inside. So, I put it back together and turned the filter back on, and the pressure is still 4. Any ideas why the filter isn't accepting the D.E.? Any help would be appreciated.

    The pool is 20,000 gallons and the filter is 60 sq. ft.

  2. Back To Top    #2
    If it's going back into the pool, there has to be a breach some where in the grids or piping inside the filter. I had this problem once, I could not find a hole but changed out 3 questionable grids and the problem went away. One of them had a hole, I just did not find it.

    How old are the grids?
    In Ground Plaster Pool
    20000 Gallons
    Ecomatic SWCG
    1 HP WhisperFlow Pump
    Pentair FNS Plus 48 DE Filter

  3. Back To Top    #3
    JasonLion's Avatar
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    It is also possible to have the grids installed in the wrong positions such that water can go through without being filtered.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  4. Back To Top    #4
    I have had the pool for 4 years and I don't think that we have ever changed the grinds. The previous owner had it for 3 years but I am not sure if he ever replaced the grinds.

    I took another look at it and found a crack in the plastic part that holds the grinds together (I think its called the manifold). I vaguely remember the same crack being there last season and not having a problem...do you think that could be causing the leak?

  5. Back To Top    #5
    Yes.
    In Ground Plaster Pool
    20000 Gallons
    Ecomatic SWCG
    1 HP WhisperFlow Pump
    Pentair FNS Plus 48 DE Filter

  6. Back To Top    #6

    Join Date
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    Central Texas
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    I can see SOME of the DE leaking back to the pool from such a small crack, but not all of it. Are you certain that the water valve wasn't in the "recirc" position when you dumped the DE into the skimmer? That would bypass the filter completely. 8)
    26,000 Gallon Gunnite IGP
    2 HP Challenger High Head Pump
    60sf Nautilus DE filter
    Polaris 280

  7. Back To Top    #7
    I am positive it was in the "Filter" position. Even if the D.E. did by pass the filter when it was added, wouldn't it slowly begin to coat the filter once the water containing it was filtered?

    Anyway, I guess that that crack is probably at least part of the problem. Would that also account for the low pressure (4 psi) in the filter?

    Thanks for all your help so far.

  8. Back To Top    #8

    Join Date
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    4 PSI is very low, at least when compared to my DE filter. Mine is around 13 PSI when clean.

    One other thought... Have you bled the air from the filter tank? The DE can't coat the grids unless the water level in the tank can reach them. It seems to me that if the tank is full, then most of the water would pass through the grids, leaving the majority of the DE behind.

    I suppose that if the water level is very low and the bottom manifold is cracked then the DE would find its way back to the pool.
    26,000 Gallon Gunnite IGP
    2 HP Challenger High Head Pump
    60sf Nautilus DE filter
    Polaris 280

  9. Back To Top    #9
    I bled all of the air out of the tank before I added the DE and after took the tank apart to look at it inside. All the water is filling the tank.

    Also, I am pretty sure than only the top manifold is cracked. If this is the case, shouldn't only the top part of the grinds not have D.E. on them?

    And one more thing When I do get this problem solved, should I add more D.E. or let the D.E. that is in the pool coat the filter?

  10. Back To Top    #10
    What brand of filter is it?

    Did you take it all apart and examine each grid, especially the ends?

    Once you get it fixed I would vacuum to waste if you can and reload with fresh DE.

  11. Back To Top    #11
    It is a Pentair FNS Plus 60.

    I am going to take it apart again tomorrow and throughly examine everything. Should I be looking for anything else besides rips and holes?

  12. Back To Top    #12
    You need to check the spider gasket in the multi port valve as well as the o-ring on the stand pipe. If either of these are bad the DE will also bypass the filter.

  13. Back To Top    #13
    JasonLion's Avatar
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    Silver Spring, MD
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    37,887
    Also, if you skip the rinse step when backwashing, small amounts of DE can get into the pool.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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