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Thread: Yellow "sand" on walls of pool

  1. Back To Top    #1

    Join Date
    Jul 2012
    Western KY

    Yellow "sand" on walls of pool

    I'm opening the pool and have gotten all the gunk out of the bottom. I have a yellow grit on all the walls of my pool. I have tried to scrub this stuff off but I think it's on there with super glue! Any ideas? I can add pictures if I need to.
    25,000 gal; above ground
    sand filter
    Hayward Power Flo Matrix 1.5HP, 34GPM
    June 2009

  2. Back To Top    #2
    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: Yellow "sand" on walls of pool

    Gritty tends to point to calcium scale. It can very easily get algae or iron embedded in it as it forms.

    Pictures will help a lot. So will test results.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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  3. Back To Top    #3
    BoDarville's Avatar
    Join Date
    Jun 2012
    DFW, Texas

    Re: Yellow "sand" on walls of pool

    Lee J

    Welcome to TFP

    Pics would certainly help. Here are a couple of suggestions:
    • 1. If you have a trichlor tab, rub that on part of the stain. If it fades, then it is organic in nature (in your case, it could be mustard algae based on your description).
      2. If you have a Vitamin C tablet, rub that on part of the stain. If it fades, then it is a metal stain. If the Vitamin C is in an enclosed capsule, you would need to break the capsule open so that the actual Vitamin C gets in contact with the stain. A tablet form of Vitamin C is best to use.

    Either type of stain can also be embedded in calcium scale as Richard320 has pointed out.
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