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Thread: Splotchy New-ish plaster. No Drain Acid Wash?

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    Splotchy New-ish plaster. No Drain Acid Wash?

    Hi! I have a VERY dirty/dusty yard. (no grass). I get a lot of silt into my pool, and weekly, I vacuum and sweep the pool.

    I also just had my pool re-plastered white, 10 months ago. I maintain my water using the TF 100 kit religiously each week using the BBB method, keeping all measurements in the safe zone, except I keep the ph around 7.5-7.8 to get the chlorine to work better.
    About 3 months into the new plaster, I started seeing a 2.5 foot thick ring forming 1/2 way into the pools deep end, all the way around the deep end. And also a splotchy/dirty looking floor of the shallow end. After 10 months now, Its a pretty dark ring, and dark splotchy floored shallow end. I called the plaster company. They came out and told me that the Cl can settle into a layer after the pump turns off, and its causing the pH to rise at that midway point in the pool, casing scaling at the walls but only at that part of the pool. This sounds like BS to me. They said 7.5pH-7.8pH is too high ad could be exacerbating the problem, and I should keep it around 7.0pH-7.2pH and sweep it like crazy for a few months to bring down the scaling that's trapping the silt when I sweep. They also suggested using a 50% metal 50% poly brush. Over a few months they said I should be back to normal. As a test...They used a fine grit sanding disc and rubbed it lightly on a small section of the bottom of the shallow end and it *seemed* to work to remove a small part of a dark area, all in a small puff of white plaster that came off along with it... but it was hard to tell.

    Is this legit?! Or should I just do a non-drain acid wash for a few days? Thanks!!

    BTW- No heater, water temp is between 68-80deg (winter to summer) in Los Angeles.






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    Join Date
    Jul 2011
    Location
    Arizona & California
    Posts
    770

    Re: Splotchy New-ish plaster. No Drain Acid Wash?

    Have you felt the plaster in both the dark stained areas and next to them where the plaster is still white to determine whether it is smooth or rough?
    Either the sanding worked or it didn't. Perhaps you could purchase some wet-or-dry 100 grit sandpaper and see if the dark areas are easily removed within seconds.
    If it does, then it is calcium scale staining. If not then perhaps you have gray mottling discoloration in the plaster.
    It is very possible that when the pool was new, some plaster dust hardened on the surface (which is white) and then over time, the dirt that falls into the pool attaches to the calcium scale and turns it brown.
    Obviously, dirt is brown, but can make the scale turn a more darker gray color over time. So it is hard to say. But a few seconds of sanding should give you an indication of what the problem is.

    What are your water test parameters?

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    Re: Splotchy New-ish plaster. No Drain Acid Wash?

    Thanks for the advice. I'll try this tomorrow and report!

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    Re: Splotchy New-ish plaster. No Drain Acid Wash?

    CH 320
    TA 80
    pH 7.6
    FC 6
    CC 0
    CYA 35

    That's the numbers.

    CYA was real low last week and I added more. Probably could be slightly higher I suppose!

    I Will get in there with some sandpaper in a few days to see what it does.

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    Join Date
    Jul 2011
    Location
    Arizona & California
    Posts
    770

    Re: Splotchy New-ish plaster. No Drain Acid Wash?

    Water readings look pretty good.
    And while you are at it, I am curious to know what the TA and CH is of your tap water.

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