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Thread: dark plaster calcium stains

  1. Back To Top    #1

    Join Date
    Apr 2014
    Bakersfield, California

    dark plaster calcium stains

    Pool was re-plastered May 2014 with colorscapes dark grey. In November, CH went to 700 and white calcium stains began to appear on pool surface. Drained pool and refilled in November to lower CH. Tried Leslie's scale & stain remover for a couple months with no results.

    How can i remove these calcium spots without draining pool and acid wash?
    Is there a no drain acid wash method or product that will be effective in removing calcium stains?

    Here are my current pool chemistry readings:

    20K gal colorscapes dark gray plaster, no SWG, BBB method, variable speed hayward ecostar pump, pentair cartridge filter, hayward navigator cleaner.

  2. Back To Top    #2
    Mod Squad Patrick_B's Avatar
    Join Date
    Jun 2011

    Re: dark plaster calcium stains

    If you're history looks like that it's not indicative of calcium scaling. Certainly not a lot of potential. That's just a snapshot, so I can't say what else has happened. Still, those are good numbers from a scaling potential standpoint.

    Any chance you can throw up some photos and more history?
    TFP Moderator
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  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: dark plaster calcium stains

    There are chemicals that can prevent additional scaling, but they are far less effective at removing scale once it has already formed.

    I don't recommend a no-drain acid wash. It shortens the lifetime of your plaster more than needed, takes quite a while, requires bypassing the heater (if you have one), and often doesn't end up working.

    If the white areas are very localized you can sometimes remove them with local application of muriatic acid (through a piece of pipe). But that quickly becomes impractical as the area affected gets larger.

    Unfortunately, a full drain manual acid wash is by far the most effective approach.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  4. Back To Top    #4

    Join Date
    Jan 2013
    Friendswood, TX

    Re: dark plaster calcium stains

    Could a prolonged time with a lower than normal PH remove the stains if they are light?
    19x40 IG including 10' BE, 18,000 gal, plaster, 48 SF DE, 1.5HP pump, AquaPure SWCG, Ozonejoe 30MR, Rockwaterfall, LED light, TF-100 Fill date 11/21/2014
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  5. Back To Top    #5
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: dark plaster calcium stains

    How could your CH possibly have risen to 700ppm in 6 months? Especially given that you have now had water in it for 5 months and the CH is only 260ppm?

    That does not seem normal ... unless you were adding a lot of cal-hypo chlorine powder.

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    How are you testing your water?
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