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Thread: White deposits on pools walls

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    White deposits on pools walls

    I have an aggregate surface that was installed last May. I have developed black algae spots on the walls and floor and I am currently treating with an algaecide (also brushing and keeping chlorine level high). I have noticed these white spots forming on the pool walls that can easily by scraped off with a plastic putty knife or even your finger nail. They are typically below the water line. This is the results of my last test:

    Total Chlorine: 3.0
    Free Chlorine: 3.0
    pH 7.4
    Alkalinity 90
    Calcium Hardness 325
    Stabilizer 60
    Total Dissolved Solids 2,000

    I am using Chlorine shock and tabs also adding a sequestering agent to prevent metal stains.
    Pool is aggregate, 20,000 gallons with a cartridge filter and is using liquid shock and chlorine tablets.

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    Mod Squad mknauss's Avatar
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    Re: White deposits on pools walls

    Welcome to the forum!

    I assume you do not have your own test kit? We rely on pool owner testing not pool store. I suggest you get a proper test kit.
    The Taylor K2006C or the TF100.

    What is the algaecide you are using? We rarely recommend the use of any algaecide - and specifically warn of using any with metal in them.

    Read this on Black Algae -- Pool School - Black Algae

    We also use a SLAM to combat algae. You need your own proper test kit to complete one.

    Read this Pool School - How to Chlorinate Your Pool and Pool School - Chlorine / CYA Chart

    Take care.
    6000 Gallon IG Fiberglass with integrated Spa;Pentair CCP240 Cartridge Filter with Pentair Intelliflo VS Pump and HTR250 heater. IC40 SWG. EasyTouch 4. Dolphin Active20 Robot "Roadrunner", TF 100 Test Kit w/SpeedStir!
    CLICK HERE to Become a TroubleFreePool.com Supporter!! Pool Math App
    Marty

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    Mod Squad Jimrahbe's Avatar
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    Re: White deposits on pools walls

    c,

    I am not sure what the white spots are, but I can tell you why you have algae and why it is not going away...

    The basic principle of TFP pool care is maintaining an FC level that changes based upon your CYA level... With a CYA of 60, the very minimum your FC should be is 5 ppm and it really should be 8 ppm.

    See this chart... FC/CYA Chart You say you are keeping your chlorine level 'high", but at 3 ppm, it is well below the minimum... And, to kill visible algae, your FC needs to be 24 ppm.

    I suggest you read through our Pool School, starting with this link.. Pool School - Getting Started

    Thanks for posting,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

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    Re: White deposits on pools walls

    Quote Originally Posted by Jimrahbe View Post
    c,

    I am not sure what the white spots are, but I can tell you why you have algae and why it is not going away...

    The basic principle of TFP pool care is maintaining an FC level that changes based upon your CYA level... With a CYA of 60, the very minimum your FC should be is 5 ppm and it really should be 8 ppm.

    See this chart... FC/CYA Chart You say you are keeping your chlorine level 'high", but at 3 ppm, it is well below the minimum... And, to kill visible algae, your FC needs to be 24 ppm.

    I suggest you read through our Pool School, starting with this link.. Pool School - Getting Started

    Thanks for posting,

    Jim R.
    Most of these test kits don't have chlorine level readings up to 24 or even 8. The one I have only goes up to 5. Do you have a special test kit?
    Pool is aggregate, 20,000 gallons with a cartridge filter and is using liquid shock and chlorine tablets.

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    Mod Squad mknauss's Avatar
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    Re: White deposits on pools walls

    See post #2.
    6000 Gallon IG Fiberglass with integrated Spa;Pentair CCP240 Cartridge Filter with Pentair Intelliflo VS Pump and HTR250 heater. IC40 SWG. EasyTouch 4. Dolphin Active20 Robot "Roadrunner", TF 100 Test Kit w/SpeedStir!
    CLICK HERE to Become a TroubleFreePool.com Supporter!! Pool Math App
    Marty

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    Re: White deposits on pools walls

    I have used this method of super chlorination and over the past week, I have noticed an improvement but now the stains are smaller (tiny black spot in the middle of a larger gray circle) but still noticeable. I have also used a dose of Silvertrine algaecide which helped a bit. I would like to speed things up a bit as I have put my house on the market and I would like the pool to look nice. I have been told that drain/acid wash will not kill black algae. Short of re-plastering is there another method that will work quickly?

    If I use another dose of Silvertrine (colloidal silver) do I risk staining the pool surface?
    Pool is aggregate, 20,000 gallons with a cartridge filter and is using liquid shock and chlorine tablets.

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    Re: White deposits on pools walls

    Quote Originally Posted by cman227 View Post
    I have used this method of super chlorination and over the past week, I have noticed an improvement but now the stains are smaller (tiny black spot in the middle of a larger gray circle) but still noticeable. I have also used a dose of Silvertrine algaecide which helped a bit. I would like to speed things up a bit as I have put my house on the market and I would like the pool to look nice. I have been told that drain/acid wash will not kill black algae. Short of re-plastering is there another method that will work quickly?

    If I use another dose of Silvertrine (colloidal silver) do I risk staining the pool surface?
    Also my PH readings are high when my level of chlorine is this high. Should I continue to ignore the PH readings for bring down my chlorine level?
    Pool is aggregate, 20,000 gallons with a cartridge filter and is using liquid shock and chlorine tablets.

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    Mod Squad Jimrahbe's Avatar
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    Re: White deposits on pools walls

    c

    What is normally done, is that the IntelliFlo is connected to the input(Line) side of the timer, so that it gets constant power.. Then the SWCG is connected to the output(Load) side of the timer so that it only get power when the timer allows it. Then you set the timer on/off dogs so the that the SWCG only gets power when the pump is scheduled to run. The pump runs based upon the schedule you set in the control panel on the pump itself...

    Thanks,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

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