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Thread: New plaster stains

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    Stu7's Avatar
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    New plaster stains

    Split off of this topic. JasonLion

    Hello all,

    I am newbie here and not trying to highjack this tread but have recently came across the same issue with my pool surface in the last few weeks. I am trying to stop it in it's tracks before it gets out of hand. Can you provide any update on how you treated this? Is a metal brush or pumice stone better? Did you use any additional chemicals on the surface when treating this other than keeping you balance under control? My finish is white plaster.

    I am expecting my TF-100 Kit to arrive in the next few days and will post my results then but wondering what else, if anything I can do to bring this under control?

    Thanks in advance.
    Stuart
    11,5K freeform gunite with white plaster; Pentair WhisperFlo 2HP; Hayward Pro-Grid DE 7220; Rainbow 320, Polaris 280, P4 Wireless

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    dmanb2b's Avatar
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    Re: New plaster stains

    Welcome to TFP

    Keeping your PH below 7.8 at all times is the first line of defense. Other option would be to lower you calcuim level. For now just check your PH and when you get the kit, post up some pics and a full set of test results and we'll try to help you out
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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    Richard320's Avatar
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    Re: New plaster stains

    Quote Originally Posted by Stu7
    Hello all,

    I am newbie here and not trying to highjack this tread but have recently came across the same issue with my pool surface in the last few weeks. I am trying to stop it in it's tracks before it gets out of hand. Can you provide any update on how you treated this? Is a metal brush or pumice stone better? Did you use any additional chemicals on the surface when treating this other than keeping you balance under control? My finish is white plaster.

    I am expecting my TF-100 Kit to arrive in the next few days and will post my results then but wondering what else, if anything I can do to bring this under control?

    Thanks in advance.
    Stuart
    The biggest thing I've been doing is changing the water. I can't just empty it all and refill, because we're under water restrictions here. Despite massive rainfall, they still haven't lifted it. So what I do is pump out a few inches and water the lawn with it, then refill. And I put one of those plastic downspout diverters so I get roof runoff into the pool when it rains. The water I pump out goes to the street; it's already raining, so it gets diluted plenty. With my arrangement, 1" rain = 3" pool = 5% dilution. I also have been keeping CSI in the negatives. Typically -.4 or so. Pool Calculator will tell you what CSI is when you enter your test results. And then I use a stainless steel brush.

    When it's swimmable, I usually grab the 6" algae brush and use it by hand while I'm in the pool. I'm not trying to scour it off, just microscratch it to increase the surface area which lets the water do it's work.

    It's not all gone, but it's improving week by week.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Stu7's Avatar
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    Re: New plaster stains

    Thanks guys for your feedback.

    Just received my test kit today so after a few attempts here are the numbers:

    FC 13
    PH 7.6
    CC 0
    TA 180
    CH 300
    CYA 100

    I tried to take a picture but it is still quite bright outside and although it looks like the same pattern & detail as above too the naked eye I cannot get the image on camera...yet?

    I think I will start to drain off bit by bit and refill after I have tested my source water.

    Any other tips other than a brush & patience?
    11,5K freeform gunite with white plaster; Pentair WhisperFlo 2HP; Hayward Pro-Grid DE 7220; Rainbow 320, Polaris 280, P4 Wireless

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    JasonLion's Avatar
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    Re: New plaster stains

    This doesn't really relate to your question, but your CYA level is too high. The common CYA test will read anything over 100 as 100, so it might be way too high. The only practical way to lower the CYA level is to replace water.

    Your TA level is too high, and that is probably the root cause of your problem. Take a look at the lowering TA article in Pool School.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Stu7's Avatar
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    Re: New plaster stains

    Thanks Jason,

    I am working on lowering my TA as I admit I must have let it and my PH drift. How quickly would you expect TA to drop? Is it possible to drop by 50 in a matter of days? I ask as I measured 180 on Thursday and have got to 130 this morning. I have been keeping my PH in the 7.2 range.

    Many thanks,
    Stuart
    11,5K freeform gunite with white plaster; Pentair WhisperFlo 2HP; Hayward Pro-Grid DE 7220; Rainbow 320, Polaris 280, P4 Wireless

  7. Back To Top    #7
    JasonLion's Avatar
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    Re: New plaster stains

    TA goes down most quickly at the start, and slows down as you approach your goal. The actual rate varies quite a bit, depending on how much aeration you have.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Stu7's Avatar
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    Re: New plaster stains

    I retested today and my PH and TA seem to have dropped quite a bit. New results are:

    FC 9
    PH 7.2
    CC 0
    TA 110
    CH 300
    CYA 100

    I am now working to replace water to reduce CYA.

    What would the next step be? I have noticed a product called Scaletec, would this be any use in removing the stains in additional to a brush and some elbow grease?
    11,5K freeform gunite with white plaster; Pentair WhisperFlo 2HP; Hayward Pro-Grid DE 7220; Rainbow 320, Polaris 280, P4 Wireless

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    Re: New plaster stains

    Get the CYA down first. That means either dilution or a Reverse Osmosis treatment, if available.

    The correct level of Free Chlorine (FC) is determined by that. After CYA hits 100, it's very difficult to
    A) get an accurate reading
    B) Know where your regular FC should be
    C) Know where your shocking level is when needed
    D) know where your real alk level is (CYA affects it too)

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Stu7's Avatar
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    Re: New plaster stains

    Scott,

    Thanks for the input.

    After some dilution I have retested and this is where I am now:
    FC 7
    PH 7.5
    CC 0
    TA 100
    CH 290
    CYA 90

    My pool does get 10+ hrs of direct sunlight. Am I correct in thinking my CYA should be in the range of 60-80? Current water temp is 67.

    I am still working on dilution and will retest again the next few days.

    Thanks,
    Stuart
    11,5K freeform gunite with white plaster; Pentair WhisperFlo 2HP; Hayward Pro-Grid DE 7220; Rainbow 320, Polaris 280, P4 Wireless

  11. Back To Top    #11

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    Re: New plaster stains

    A CYA of 60 to 80 ppm is a tad high for a non SWCG pool. If you are running a SWCG, then 60 to 80 is where you want to be. But, if you are running a regular ol' chlorine pool, you want to be somewhere between 30 to 50 on the CYA. Now, if the sun really beats down on your pool heavy during the dog days of summer like some folks' in Arizona do, then a little extra CYA, say, up to 60 ppm, might be beneficial.

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    Stu7's Avatar
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    Re: New plaster stains

    Not sure if this requires a new thread but essentially I have the same issue as I did last year as the stains have returned. I am at my wits end as what to try to get rid of these and prevent these recurring. I think I have read so many threads on here I have confused myself between organic stains, metal stains, copper scaling and the treatments for each of them....

    I have been more vigilant this year in trying to get/keep my CYA down (Previously 100+) and have moved from pucks to liquid chlorine. I completed the chlorine puck test and it did seem to lift most of the stain when I left it in place for 15 minutes. So I went through the shock process, however it did not significantly lift or reduce the stains. I then tried the Vit C test but that did not lift anything.

    The worst areas seem appear to be at my main drain and on some of the walls. The plaster remains smooth to the touch. Regular brushing seems to have little to no impact on removing them.

    I am genuinely confused as to the best course of action and looking for some sound advice on the best next steps. Would appreciate some pointers I can take over the next few weeks to help me at least identify then correct this. Don't be afraid to spell it out in detail.

    Thanks in advance,
    Stuart

    Here are my latest results

    FC 7
    CC 0
    PH 7.8 (adjusting this down slightly)
    TA 70
    CH 200
    CYA 50



    11,5K freeform gunite with white plaster; Pentair WhisperFlo 2HP; Hayward Pro-Grid DE 7220; Rainbow 320, Polaris 280, P4 Wireless

  13. Back To Top    #13

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    Re: New plaster stains

    Your pool water balance is fine. IMO, your pool plaster looks like it has gray mottling discoloration. Read my post titled "Gray Mottling Discoloration" in the Deep End section.

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