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Thread: Problem with brand new gunite pool

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    Problem with brand new gunite pool

    Our pool was built in March of 2012 in Ohio. I tested ph and chlorine daily and had everything else tested 1-2 times a month at a local pool shop, nothing was ever "off" except the ph which was always high so I added about 3 gallons of muratic acid every 10 days. When the pool was opened this spring it had spots all over the bottom. When I contacted my builder I was told it was calcium deposits and that I had not balanced my water, the calcium was high. I had taken my water to get tested before closing, the day after it was opened and the only thing off was the ph which was so high they couldn't read it. I again took the water to get tested and the calcium was still fine. I told the contractor this and they told me I had to sand the pool. I then found another pool that the contractor built that has this same issue. Now the contractor admitted that the issue was "bad plaster" and was told he would sand it, he never finished the job. Now once again they have flipped back to telling us it is bad water chemistry and not their problem. Do you know what causes this in a pool that was not even a year old? We are sick! And totally expecting the same when we open our pool next spring.

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    linen's Avatar
    Join Date
    Jul 2010
    Twin Cities, MN

    Re: Problem with brand new gunite pool

    Welcome to tfp, CARISD

    Sorry to hear about your pool surface problems. High ph can cause scaling when other pool parameters are also off. Can you post your last full set of test numbers particularity ph, TA, CH, cya, salt level (if added), borate level (if added). From these we can look to see if you have potential for scaling.

    Also, if you can post a decent picture of the issue it might help.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Problem with brand new gunite pool

    Welcome to the forum. .

    Your post needs some clarification. Tell us the size of your pool.

    Controlling pH is essential in the start up of a new plaster pool. How often since opening have you added muriatic acid to keep pH in the 7's. I see the addition of 3 gallons of acid (which would've meant your pool pH may have been over 10.5 ????) but were you shooting for a target? Did you add any other acid to try to control it?

    The CH of your pool is important in contributing to calcium scale but it's the pH that is the most important factor and that needs to be managed constantly....especially on a new plaster pool.

    Are you positive the "spots" are calcium scale? Can you post a pic?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Problem with brand new gunite pool

    My pool is 16x36 and 3' to 8'. It has a marbelite plaster finish. I'm not positive it's calcium, that's what the contractor is telling me. Last year about every other day my ph would raise to around 7.8 every other day and I would add muratic acid, nothing else. I was told that was to be expected with the gunite pool. This year I kept it around 7.2-7.4, it was much more manageable. The only time it was at 10 was at opening this year. Nothing else has ever been off on it. This year a pool guru had me try to keep my levels at the following to control this, it has been still going on even with the ph at 7.2:
    Chlorine 1.5
    pH 7.2
    Alkalinity 70 ppm
    Calcium 250
    Stabilizer 60

    At close last year was at:
    Chlorine 1.0
    PH 7.2
    Alk 120
    Stab 30
    Calcium 350
    Salt 3100

    At open this year:
    Chlorine 5
    PH 10+
    Alkalinity 100
    Stab 30
    Calcium 350
    Salt 3100

    At close this year:
    Chlorine 1.0
    Ph 7.4
    Alkalinity 70
    Stab 50
    Calcium 320
    Salt 3100

    I'll have to make my pictures smaller to download

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    Re: Problem with brand new gunite pool

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