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Thread: is my new plaster ruined?

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    is my new plaster ruined?

    background - had my pool marble dusted (re-plastered) in mid may this year. i kept it w/o salt water for about a month and a half. everything seemed great except i had a hard time keeping the ph down. was adding about a quart a week it felt like. it stabilized a little better by Sept, but still needed some every week. and then..

    i had to be out of town from about late sept to early nov. i usually do my own maintenance, but wanted to have someone take care and close it while i was away. unfortunately there was a mix up and nothing was done for the month and a half. so i balanced the water, and started cleaning/closing. the solar cover was on and the pump was running so it actually was not too bad. however the ph was way too high and both TA and calcium were at upper recommended range. i balanced (took a gallon of acid) and once i started draining i spotted what looks like cracks with some form of hard mineral looking substance coming out of the crack (pic attached - note 2 things 1. i was hanging upside down so the pick is upside down 2. i have grey plaster with a molten look so the strange color is fairly normal except it looks like it faded a bit from May). on closer inspection i also noticed that the plaster was very, very rough. it looked like there was hardened, coarse grain salt stuck to the plaster everywhere. it does scrap off with a bit of sandpaper and elbow graese but i couldn't imaging wet sanding the entire pool.

    any ideas of what to do now? i've balanced and drained/covered for winter but am stressed thinking that i'm going to have to pay for another plaster job next year!

    any help is greatly appreciated.
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    long island ny, 18K gal gunite, Aquarite SWG, pentair intelliflo pump, Hayward sand filter (top mount),
    Starite 400K btu heater

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    Mod Squad jblizzle's Avatar
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    Re: is my new plaster ruined?

    Welcome to TFP!!!

    Everything you describe sounds very much like calcium scaling (the rough, whiteish deposits) and that happens when your pH, and CH are high. As you stated, sounds like the conditions were right for it to develop while you are gone.

    If you can lower the CH (water replacement) and maintain the pH at the low end of our recommendations and brush a lot, the scale will eventually start to reduce. Alternatively, I think you can do an acid wash to try to remove the scale, but I have no experience with that.

    I am sure other members that have dealt with this sort of thing will soon be around to comment.
    Jason, TFP Moderator
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    Re: is my new plaster ruined?

    thanks very much. i figured it was some form of mineral deposit so i balanced (lowered ph and replaced some of the water to get the ta and calcium down). had to close it up for winter as it is starting to freeze at night but hopefully the technique you describe will work.

    do you think the crack with the deposits oozing out are the same?

    thanks again for the help
    long island ny, 18K gal gunite, Aquarite SWG, pentair intelliflo pump, Hayward sand filter (top mount),
    Starite 400K btu heater

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    y_not's Avatar
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    Re: is my new plaster ruined?

    Is that "crack" in a place that you can get to it to try and scrape at it with your nail? See if it really feels like a crack, or if it's raised.
    You can try some 100 grit wet/dry sandpaper on it to see if it goes away. If it does, it's not a crack.

    I might have missed this, but are these "cracks" all over the pool? What does it look like as far as these "cracks" go, overall? IE. How many are there.

    Otherwise, jblizzle is spot on with the prognosis of your pool.
    Also, please post a full set of test numbers.

    Thx.
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    Re: is my new plaster ruined?

    Your pool plaster is experiencing two separate and different problems.
    1. As jblizzle mentioned, the uniform roughness everywhere is calcium scale cause by high pH (unbalanced water).
    2. It appears that the plaster also has some cracks due to delamination (bond failure) of the new plaster from the old original plaster or substrate in specific areas or places. When delamination occurs, the plaster usually "cracks" and "calcium nodules" form along the cracks or pinholes. The nodules are a symtom of the bond failure problem and not due to improper water balance. Nodules can be sanded off, but more nodules will form again on the (permanent) cracks in time. When the calcium "bleeds" out of the crack areas on pool walls, they will form downward (from cracks) due to gravity, as in the case of your picture. To confirm and be certain, "tap" along the crack area with the handle of a screwdriver or something else, and it will have a "hollow" sound. Tapping away from any cracks and nodules will sound solid and tight.

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    Re: is my new plaster ruined?

    I think you are right about the cracks - when I was draining the pool, I noticed that the area around the crack seemed to be bubbled up a but. I'm going to call the builder to see if they will fix it. Is there anything that can be done short of redoing the entire pool? Can they spot fix it?
    long island ny, 18K gal gunite, Aquarite SWG, pentair intelliflo pump, Hayward sand filter (top mount),
    Starite 400K btu heater

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    Re: is my new plaster ruined?

    The builder might be able to fill in the cracks with cement if the plaster layer is thick. However, if the plaster is thin, in time the plaster might break away where the delamination is. Patching the where the plaster has delaminated will show up significantly and look very different. Won't be able to match the color of the rest of the pool. The amount of delaminated areas need to be determined. Re-plastering entire pool may be only viable option.

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    Re: is my new plaster ruined?

    Quote Originally Posted by onBalance
    The builder might be able to fill in the cracks with cement if the plaster layer is thick. However, if the plaster is thin, in time the plaster might break away where the delamination is. Patching the where the plaster has delaminated will show up significantly and look very different. Won't be able to match the color of the rest of the pool. The amount of delaminated areas need to be determined. Re-plastering entire pool may be only viable option.

    I agree with the second portion of your post. Patching ( yuck) or replastering are the only viable option.
    20X40 30,000 gallon gunite pool

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    Re: is my new plaster ruined?

    Thanks all. Called the company that does the dusting and they will come out and look. Probably not till spring though since they are closed and out of town for winter.

    So they will look at the delamination. For the calcium scale, should i keep the water a little aggressive and do extra brushing? If so, how aggressive, and for how long?

    Thanks again for all the great info
    long island ny, 18K gal gunite, Aquarite SWG, pentair intelliflo pump, Hayward sand filter (top mount),
    Starite 400K btu heater

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