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Thread: Pool contractors answer to Gray Mottling

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    Pool contractors answer to Gray Mottling

    Gray Mottling=Plaster discoloration. New plaster 8 months ago. Always followed BBB method. Finally got contractor to take a look at why pool plaster has lots of discoloration. Never added Borate, didn't think it was necessary. Only fill pool with city water.
    Test water 5x week, 1x month compare to pool store results.
    Not sure if contractor is making excuses to get out of crappy install with plaster mix.
    Current test results:
    Free Chlorine=3.75
    Total chlorine=3.75
    CC=0
    PH=7.8
    Hardness=400
    Alkalinity=my results 70, his testing 45
    CYA=43
    cooper=his testing 0.1
    iron=his testing 0.2
    borate=0
    TDS=900

    Here is the report, you have what the NPC calls the deadly duo, both low alkalinity and high calcium, this would certainly cause the look we are seeing and also cause the nodules to grow in the finish. I'd correct the chemistry as soon as possible to avoid further progression. Also there are no borates and you have a fair amount of iron in the pool. If you have any old reports like this one I'd like to see them.
    18k, IG, chlorine, plaster, sand, 12yrs, new plaster 2013, Texas

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    Join Date
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    Re: Pool contractors answer to Gray Mottling

    Do you use anything with an ingredient that says **sulfate.
    18,000 Gallon Aboveground. Sand Filter with 2HP 2 speed Pump.

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    Re: Pool contractors answer to Gray Mottling

    I have not used anything other than Liq chlorine, acid, baking soda. Got another email from contractor (below) that didn't make sense so i took it to pool store along with some water. He looked at current water sample and noted no issues other than the liquid chlorine Iíve used has increased the TDS overtime. He even looked at past results. Then we discussed contractor email which he didnít understand nor make sense. He said the current water chemistry has nothing to do with this type of discoloration, itís from the calcium hydration during startup. Since he has had this issue come up before, he gave me a contract at NPC (national plaster council).
    -use a Taylor kit which uses drops (reagents) doesnít call for calibration.
    -Used a total of 6 pucks since fill and this has not increased the hardness.
    -cooper and iron at 0, no issue
    -adding borates is not needed

    Contractor email;
    Taylor test kits all must be calibrated, also don't forget
    about the cy correction with the alkalinity readings for
    carbon alkalinity which gives you the actual reading. Your
    chemistry needs major corrections including partial
    draining. The calcium introduction is from the trichlor you
    are using, which was not mentioned in your 3 ingredient
    list. Also a test sample reduction must be performed when
    testing pools with high calcium.
    The current chemistry is damaging your finish and will
    certainly cause further discoloration. Send over the reports
    you mentioned.
    If you need a referral for a qualified pool maintenance
    professional let me know I have a few in your area.
    18k, IG, chlorine, plaster, sand, 12yrs, new plaster 2013, Texas

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    Mod Squad zea3's Avatar
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    Re: Pool contractors answer to Gray Mottling

    I'll address the problems in the contractor's email in red.
    Quote Originally Posted by Derosa

    Contractor email;
    Taylor test kits all must be calibrated, (Only kits that are read by a computer or electronic sensor must be calibrated, and then only when calibration is needed) also don't forget about the cy correction with the alkalinity readings for carbon alkalinity which gives you the actual reading. Incorrect as far as I know. Your chemistry needs major corrections including partial draining. The calcium introduction is from the trichlor you are using,(Trichlor does not contain calcium, in fact you cannot use or store calcium hypochlorite in anything that has ever held trichlor/dichlor products due to the violent chemical reaction that occurs when those two products are combined with water in the same container. Check your fill water for the calcium level. If that does not explain the high ch, and you have not added calcium to the pool, it may be leaching from the plaster. which was not mentioned in your 3 ingredient list. Also a test sample reduction must be performed when testing pools with high calcium. I have no idea what this means. The current chemistry is damaging your finish and will certainly cause further discoloration. Send over the reports you mentioned. If you need a referral for a qualified pool maintenance professional let me know I have a few in your area.
    I would get copies of the chemistry reports and photos of the plaster and keep them for my own records. I would also ask for a second opinion from a qualified pool professional of my own choosing, and ask for their opinion in writing, as well as their proposed solution to the problem. After I was armed with more information I would decide my next course of action.
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    Patrick_B's Avatar
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    Re: Pool contractors answer to Gray Mottling

    This guy is the one who needs a pro to help with chemistry. I think what he means by sample reduction is splitting a sample that reads too high for whatever method he is referring too. He does not take into account the type of testing you are doing however. I assume that is for a photospectrometer of some sort. I also think he has CYA/TA correction backwards. Although I don't believe in that nonsense. Zea has the rest covered and quite well I might add. Do save this email, it proves beyond a doubt his ineptness with pool chemistry. He is doing no more than passing the buck and blaming you. And he has obviously no idea what he is talking about.
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    Re: Pool contractors answer to Gray Mottling

    The PB is essentially telling you that he is not going to do anything about it unless you step it up a notch. I would suggest that you do one of the following: 1. ask for a meeting and present him with a report saying that the cause of the problem is poor install, demand that he take certain actions to correct or you will hire an attorney; or 2. hire an attorney and send him a letter demanding corrective action. With his response, I would probably go with option 2.

    Good luck.

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    Re: Pool contractors answer to Gray Mottling

    BINGO
    found this article which describes the issue.
    http://www.poolhelp.com/handouts/oB_Hyd ... andout.pdf

    -This discoloration develops over time, and usually appears sometime in the first year.
    -No change in water chemistry stops the progression of the discoloration.
    -"excessive hydrationĒ

    Thanks for the info. I'll see what the National Pool Council says. I understand they can come out for a small fee.
    18k, IG, chlorine, plaster, sand, 12yrs, new plaster 2013, Texas

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