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Thread: DE filter not filtering? (All new grids, Water is Clear)

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    DE filter not filtering? (All new grids, Water is Clear)

    I replaced all the grids in the filter, and I'm still having dirty water being recirculated into the pool.

    There's dirt and/or dead algae sitting on the floor of the pool. I'll vacuum it all up, and let the pool sit for a couple days, and then it's all just sitting on the floor again.

    What's going on?

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    frustratedpoolmom's Avatar
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    Re: DE filter not filtering? (All new grids, Water is Clear)

    You coated the new grids with DE, correct?

    Are you sure thats just not new pollen/dust that is settling? If it was passing thru the filter - you would notice it in hours, not days. If its dust/pollen, you won't see and overnight FC loss. If you have a "nascent" algae situation - and what you see is dead algae, then you should do an overnight FC loss test to see if something organic is causing this.

    Overnight FC Loss Test
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    Richard320's Avatar
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    Re: DE filter not filtering? (All new grids, Water is Clear)

    If the old grids had tears, that might be old DE that was in the pipes being washed out.

    When your replaced the grids, you didn't hear any expensive cracking sounds, did you? And they all seated completely?
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: DE filter not filtering? (All new grids, Water is Clear)

    Yes, I applied fresh DE to the filter by mixing it in a 5 gallon bucket then running it into the filter.

    I'm positive that it's not just new dirt settling in the pool. There is a TON of it; it literally coats the bottom of the pool.

    It doesn't take days to settle, I just get real busy and don't look at the pool for a couple days at a time. As I'm vacuuming it starts blowing dirty water back into the pool, and it gets real cloudy. Pretty soon the water is clear again and everything has settled back onto the bottom.

    I dumped about two pounds of powdered shock into the pool, and then we put 8 gallons of 12.5% sodium hyperchlorate into it also (after some algaecide). It doesn't look like anything is growing in there anymore, just sitting in the bottom like dirt.

    Thank you for the feedback.

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    Re: DE filter not filtering? (All new grids, Water is Clear)

    I thought it might be residual stuff, but not anymore as I've vacuumed it up about 3 times I even backwashed the filter again and applied new D.E.

    I had help putting the grids in. We were very careful placing them all in and everything seated well without applying excessive force. Aside from the dirty water, I have no other reason to think the new grids are damaged.



    Quote Originally Posted by Richard320
    If the old grids had tears, that might be old DE that was in the pipes being washed out.

    When your replaced the grids, you didn't hear any expensive cracking sounds, did you? And they all seated completely?

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    JasonLion's Avatar
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    Re: DE filter not filtering? (All new grids, Water is Clear)

    There are a couple of situations that can cause fresh dust to rain out of the pool constantly even though the filter is catching what you vacuum up. Some of the most common ones include: dead algae when the FC level is just slightly too low. Algae is constantly growing, but never really gets going, so dead algae rains down constantly, pollen, is it pollen season where you are, and blown in dust from a major storm, which can takes three to five days to all settle out.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: DE filter not filtering? (All new grids, Water is Clear)

    But they're seeing dirty water coming from the returns when they vacuum...

    I think you should open the filter and check that everything is still seated properly. If it really is DE then the grids won't be well coated. Also check for new tears etc.

    What about the air bleed assembly? Is this still installed properly and not damaged? I mean the internal part at the top of the filter stack. On my old Hayward it was a tub with a mesh bag. On my current petair quad de filter it's a round mesh filter on top of a tube. I believe if these are damaged or missing then DE can blow out of the filter.
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
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    Re: DE filter not filtering? (All new grids, Water is Clear)

    Having just gone through something similar I say you take it apart again and re-inspect those grids. Last week after the pool guy got the system up and running and inspected all the grids 2 days later I had DE blowing back into the pool. Took the whole thing apart and didnt find anything. As I was putting it back together I noticed a hole in one of the grids on the very bottom that I missed on first inspection. 1/2 an acorn had some how gotten into the system and blew a hole in one of the grids. Things happen you know. If there is DE blowing back in the only explanation is a damaged grid. I know it is a pain to take it all apart but thats what I would do. Good luck!!!
    Cleveland, Ohio
    IG 36,000 gallons. Vinyl Liner, Hayward ProGrid 3620 DE Filter, Hayward Super Pump, Hayward Gas Heater

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    Re: DE filter not filtering? (All new grids, Water is Clear)

    It seems to be filtering at least some of the dirt... I keep vacuuming it and the floor is much cleaner than it was.

    But, now my Hayward vac isn't moving very much. Took it apart and cleaned the bearings and it's slowed down again. The vac was rebuilt last year with basically everything that could be replaced.

    I'm off to do some research on that now.

    Thank you guys for taking the time to help me out. I'm sure I'll be back here before I get this all figured out

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    Re: DE filter not filtering? (All new grids, Water is Clear)

    Welcome to TFP!!

    Is there any chance the manifold that holds the new grids is cracked? Did you check to make sure that the fabric on the grids isn't fully in place to the manifold? As carlscan suggested, how's the air relief tube? Did you check the o-ring on the stand pipe and check the pipe itself?

    Sorry for all the questions but I'm trying to point out the places that DE can bypass the filter. The last option is that the multiport gasket might be torn or warped.

    We'll get you through this, we just need to exhaust all the possibilities
    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

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