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Thread: dirt returning to the pool

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    dirt returning to the pool

    Hi I have been looking at the forum for some time and find it really useful.

    I have had the pool for 5 years and had no insurmountable problems. I now find myself a bit confused.

    When I am vaccuming the pool after about 5 minutes the water returning to the pool becomes discoloured. I assumed it was a problem with the multiport valve (it is an Astralpool 6 way) I changed the spider gasket but it made no difference. When the valve top was off I had a look and there were no obvious breaks (the spider gasket also looked OK but I kind of hoped I also backwashed the sand filter and even took the lid off the sand filter and gave it a good stir (and backwashed again!)

    So I am doing nothing different to what I have done in the past, I get the impression that not all the dirty water is going back in as it is only slightly discoloured, any ideas?



  2. Back To Top    #2
    New2Me's Avatar
    Join Date
    Jun 2008
    SW Indiana

    Re: dirt returning to the pool

    Don't backwash until you see a pressure rise from baseline.
    A "dirty" filter will usually catch finer stuff. You might want to look at adding a little DE to help your sand filter "polish" the water, or look at replacing the sand. The "sharp" sand used in filters will smooth out over time, and become less effective.
    Good Luck, and Best Wishes!
    22 x 40 IG vinyl lined, 23,570 gal.
    1 hp. Pac-Fab Challenger pump 300# sand filter
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  3. Back To Top    #3
    spishex's Avatar
    Join Date
    Oct 2008
    Hillsborough, NC

    Re: dirt returning to the pool

    Some finer debris is just too small to be captured by sand. Adding DE as suggested may help, or you can consider vacuuming to waste if you have enough water.

  4. Back To Top    #4

    Re: dirt returning to the pool

    It looks like it may be time for a sand change. If you are looking for better water clarity you may want to look into alternate media like Zeobrite or similar.
    Frank Bowman

    Authorized Dealer: Pebble Tec, Paramount, Aquamatic Covers, Pentair, Crystal Fountains, Jandy, Hayward

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: dirt returning to the pool

    Hi, John,

    I doubt changing sand will help that problem.

    It sounds like one of the laterals is broken but that's a guess.

    Since dirty water is being passed thru the filter, I don't see the multi-port valve as the problem, either.

    Have you looked inside the filter? I believe that's where the problem is and I think a phsical inspection is gonna' be your best bet to find it.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6

    Re: dirt returning to the pool

    Hi Guys
    Thanks for the info, I have had a great day pulling the sand filter apart, I have emptied the sand and cleaned it out and stripped the pipework and laterals, its now dark so investigations will continue tomorrow (I’m in Spain).

    “Don't backwash until you see a pressure rise from baseline” Thanks for that New2Me, I understand the thinking behind it and will bare it in mind in future.

    I don’t think I need the DE as up to two months ago (before the problem arose) the water was returning to the pool clear enough. So whatever problem I now have is happening after a lay off from cleaning for about 2 or 3 months

    As several of you recommended a change of sand and as I have removed it all to check out the pipework I will renew it before I start it all back up again.

    Dave S – I didn’t understand what you were referring to when you mentioned “laterals” Now I have read the manuals and stripped the filter I’m now an expert!! I see how it all works and understand your thinking. Unfortunately (fortunately!?) there appears to be no problem with the laterals (all tight and un-broken) or the attached pipework.

    You say “Since dirty water is being passed thru the filter, I don't see the multi-port valve as the problem, either”
    My thinking here is if there is a break internally in the valve then a small portion of the dirty water may go back to the pool bypassing the filter, although the majority of the water goes through the filter. Just clutching at straws as I could find nothing broken in the filter.

    The only thing I did find wrong in the filter was the cap had come off from the top of the inlet pipe. This is mushroom shape with 6mm holes so I cant see it would have caused any problems.

    I will continue looking tomorrow – thanks again


  7. Back To Top    #7

    Join Date
    Jul 2008
    Solon, Iowa

    Re: dirt returning to the pool

    Is mustard algae a possibility?
    15X30 AGP, Lomart beaded liner;
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  8. Back To Top    #8
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    SWSuburban Chicago, IL

    Re: dirt returning to the pool

    Quote Originally Posted by kjcole
    Is mustard algae a possibility?
    OP sees the dirty water returning to the pool thru the return. That doesn't indicate a Mustard Algae problem.
    Helpful links: Pool School; CYA/Chlorine Chart
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