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Thread: White stains in dark-bottom pool

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    White stains in dark-bottom pool

    I know this is probably a repost and I apologize profusely for that but I couldn't find a related topic in an existing thread.

    I have a dark-bottom pool and since about eight months after we built it, white stains have been appearing throughout. I was told it has to do with not keeping the pH levels right but no matter how diligently I track them, the spots don't seem to fade or change. They are throughout the pool and spa including over the bottom of the pool when the vaccum travels.

    I have those colored test strips for dummies and manage the chemical levels as closely as possible.

    Any advice anyone has so that I can get the pool's plaster back to its original, pristine condition?

    Thanks for your help.
    15k gal, IG plaster, Pentair Quad DE 60, Built - 2007, spa, Zodiac Pro G Plus, Eclipse Del Ozone, Pentair Master Temp 400, Pentair Intelliflo variable 3hp, Jandy Aqualink RS

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    linen's Avatar
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    Re: White stains in dark-bottom pool

    Welcome to tfp, MyOwnPoolGuy

    Quote Originally Posted by MyOwnPoolGuy
    I know this is probably a repost and I apologize profusely for that but I couldn't find a related topic in an existing thread.
    The google search box at the lower left of each page is the best way to find stuff on the site...with that said, it is fine that you are starting your own post.

    A picture or two of what you are seeing would be helpful.

    Quote Originally Posted by MyOwnPoolGuy
    I have those colored test strips for dummies and manage the chemical levels as closely as possible.
    Test strip results tend to be very inaccurate/outright misleading. You need an appropriate test kit to deal with your pool investment. See: http://www.troublefreepool.com/pool-...kit_comparison ...the tf-100 is the most bang for buck.

    We need good reliable results for FC, CC, ph, TA, CH, and cya to start helping you investigate your pools staining. If you have pool store results you can post them...but they tend to be much less reliable then the results you will get yourself with the test kits in the link above.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    JasonLion's Avatar
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    Re: White stains in dark-bottom pool

    Welcome to TFP!

    That sounds like calcium scaling, which occurs when you let some combination of PH, TA, and/or CH get too high. If it is indeed calcium scale the only reliable way to remove them is to drain the pool and manually acid wash the scaled areas.
    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: White stains in dark-bottom pool

    Ok, I just ordered the TF-100, thanks for the heads-up on that.

    I attached some images of my problem. Thanks for your help.
    Attached Images Attached Images
    15k gal, IG plaster, Pentair Quad DE 60, Built - 2007, spa, Zodiac Pro G Plus, Eclipse Del Ozone, Pentair Master Temp 400, Pentair Intelliflo variable 3hp, Jandy Aqualink RS

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    Re: White stains in dark-bottom pool

    Read this post: white-spotting-of-new-plaster-pools-t56607.html
    What sometimes happens to white plaster pools can also happen to dark colored plaster pools.

    Have you felt the white areas to see if the surface is smooth or rough?

  6. Back To Top    #6

    Re: White stains in dark-bottom pool

    Yep, it is smooth and it seems like this is exactly what may have happened in my case. Is there a cure for this or is the only option to get my pool replastered?
    15k gal, IG plaster, Pentair Quad DE 60, Built - 2007, spa, Zodiac Pro G Plus, Eclipse Del Ozone, Pentair Master Temp 400, Pentair Intelliflo variable 3hp, Jandy Aqualink RS

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    Re: White stains in dark-bottom pool

    If I am diagnosing the problem correctly based on your pictures, I highly doubt that anything can be done to make the surface color uniform and dark again.
    The white spots actually go deep (about 4 mm) and would require severe and intensive sanding to restore the consistant gray color.

    It is a plastering defect, and the plasterer should be willing to make it right by re-plastering.

    See this blog: scientific-evidence-on-plaster-spotting-t57853.html

  8. Back To Top    #8

    Re: White stains in dark-bottom pool

    Well, I finally got around to using the TF-100 test kit instead of the strips. I am a little concerned that I have been running a science experiment and not a swimming pool. I also think this may have something to do with the white spots.

    Can anyone give me a hand on first steps to getting this thing back in control or is fire the only answer?

    Total chlorine- 0.0
    pH - 7.0
    TA - 130
    CH - 3,125.0
    CYA - 100+ (I couldn't see the black dot about a quarter inch below the 100 mark)
    15k gal, IG plaster, Pentair Quad DE 60, Built - 2007, spa, Zodiac Pro G Plus, Eclipse Del Ozone, Pentair Master Temp 400, Pentair Intelliflo variable 3hp, Jandy Aqualink RS

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    linen's Avatar
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    Re: White stains in dark-bottom pool

    Are you certain about your CH number? It looks like you are using a 10 ml sample so each drop is 25 ppm CH? Then that means you would have put in 125 drops?
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

  10. Back To Top    #10

    Re: White stains in dark-bottom pool

    Unfortunately, yes. I started with a 25mL sample and got above 100 drops before I thought maybe I was doing something wrong. Then, I switched to the 10mL sample and counted to 125 drops when the mixture finally turned blue.
    15k gal, IG plaster, Pentair Quad DE 60, Built - 2007, spa, Zodiac Pro G Plus, Eclipse Del Ozone, Pentair Master Temp 400, Pentair Intelliflo variable 3hp, Jandy Aqualink RS

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    linen's Avatar
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    Re: White stains in dark-bottom pool

    It sounds like you are doing the test right.

    I have heard it mentioned on here that anything above 900 is basically unmanageable and scaling will eventually occur. Do you know or could you test what your fill water CH is?
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

  12. Back To Top    #12

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    Re: White stains in dark-bottom pool

    Drain and refill to lower CH?
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

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