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Thread: 17000 gal giunite pool black stains everywhere

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    17000 gal giunite pool black stains everywhere

    I have tried every remover product on the market following the label directions. NOTHING BUT NOTHING is aiding in the removal. Last year I used the cl free system. Had several large stains and green stains. Had pool emptied and acid washed. Changed to a salt generator and now the staining is all over... walls and floor of pool. light markings all over. Tried test kit from pool store and nothing helps. I am open to all ideas. i will attach a few pics. i will be grateful for any help you can offer.

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    JasonLion's Avatar
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    May 2007
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    Re: 17000 gal giunite pool black stains everywhere

    Welcome to TFP!

    Several of the chlorine free systems use copper. Copper can cause unsightly stains that are sometimes nearly impossible to remove. Of course, these stains might be something else.

    A couple of additional pieces of information will help us diagnose things. First, could you post a complete set of water test results? What color are the stains? Are they smooth or rough or somewhere in-between? Did they go away when the pool was acid washed and then come back, or never go away in the first place?
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: 17000 gal giunite pool black stains everywhere

    The stains did go away. Yes the old green stains were copper. The black stains appear like chalk marks but they don't rub off.
    According to pool store all chemistry was excellent.
    Attached Images Attached Images

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    JasonLion's Avatar
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    Re: 17000 gal giunite pool black stains everywhere

    That could be metal stains embedded in calcium scale. That could potentially account for why the stain tests don't remove them. I would try an old sock with a handful or two of dry acid in it sitting on the stain for 30 minutes and see if that has any effect.
    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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    Re: 17000 gal giunite pool black stains everywhere

    That sounds similar to the LEMON test. I placed a lemon on stain for 15 minutes and nothing...

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    Join Date
    Aug 2012
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    Herndon, Va
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    Re: 17000 gal giunite pool black stains everywhere

    Any luck removing the stains?
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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