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Thread: Is this etched plaster or calcium deposits (or both?)

  1. Back To Top    #1

    Join Date
    May 2014

    Is this etched plaster or calcium deposits (or both?)

    Big fan of TFP and really appreciate all of the expert advice here.
    Trying to decide whether to raise CH before closing?
    But I'm not sure what I am seeing.....

    The pool surface is quite rough - like sandpaper.
    This pic is the top step surface from the beginning of the season.
    Is this a plaster surface that has been damaged by etching?
    Or is this a plaster surface that has been damaged by calcium scaling?
    Or both?

    The whitish areas seem a little smoother than the slightly darker areas, but do not seem to be raised above the surface of the plaster.

    I assumed it was calcium deposits, so kept the CH a bit lower (150) - but managed the pH to keep the CSI close to zero. Over the season some of the whitish areas have disappeared.
    But the pool surface is still rough.
    Never seen a new plaster pool so I'm not sure what I should be seeing.

    Thanks for any advice.

    FC 5.4
    CC 0.0
    CH 150
    TA 100
    pH 7.8
    CYA 30
    30k gallon inground gunite, Pentair Intelliflo VS pump, Sta-Rite System 3 Catridge Filter, 2 main drains, 2 skimmers, 4 wall returns, 2 floor returns, 2 Jandy valves, 2 underwater lights (hey, I didn't design this thing...), LoopLoc safety cover for the winter, average chlorine usage over 3 years: 1.2ppm/day, using 12.5% sodium hypochlorite ($3/gal) and following TFP PoolMath directions. Works great!

  2. Back To Top    #2

    Join Date
    Sep 2016

    Re: Is this etched plaster or calcium deposits (or both?)

    My plaster pool, after it was acid washed, was smooth and white. By smooth I mean if your hand is wet, it would slide over it with no discernible friction or rough feel.
    Jon -- 28kgal, IG, AquaBright, Attached Spa, ~1990, Quad DE 80, Easytouch8, IntelliFloVS-3050, Intellichlor60, IntelliPh, Dolphin DX6, City Water, K-2006/TF-100, SpeedStir, SampleSizer, San Diego, CA

  3. Back To Top    #3

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Is this etched plaster or calcium deposits (or both?)

    Calcium deposits are caused by pH too high. Plaster etching by pH too low.....both over a long period. Do you have any idea whether your pH was high or low? (Not overnight, either......this would have to be weeks and likely months or years)
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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