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Thread: FC and CYA WAY off???

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    Join Date
    May 2008
    Location
    SE Texas
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    18

    FC and CYA WAY off???

    Here are my numbers using the TF test kit:

    FC 1.5
    CC 0
    ph 7.5
    T/A 110
    CH 350
    CYA (never lost site of the black dot)
    Temp 103
    Salt level 3000
    Salt Test Strip indicates 3600

    I noticed some small black spots last week and cranked up the cell to 100%. FC level has not budged. Does this mean the black spots are Algea?

    The pool looks great except for those very small black spots in a few places. I've tried scrubbing but they don't dimish in size or color.
    18x36 Gunite w/7' spa, Whisper Flow 2HP Pump FNS DE 60 sq.ft Filter, Letro Jet Vac, Minimax Heater 400,000 BTU, Goldline Aquarite

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    duraleigh's Avatar
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    Apr 2007
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    Sebring, Florida
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    Re: FC and CYA WAY off???

    Quote Originally Posted by plumin
    Here are my numbers using the TF test kit:

    FC 1.5
    CC 0
    ph 7.5
    T/A 110
    CH 350
    CYA (never lost site of the black dot)
    Temp 103
    Salt level 3000
    Salt Test Strip indicates 3600

    I noticed some small black spots last week and cranked up the cell to 100%. FC level has not budged. i turned the water off so that we could take a shower and then turned it back on, left, and when we came back the water is a brown color.

    The pool looks great except for those very small black spots in a few places. I've tried scrubbing but they don't dimish in size or color.
    Almost surely, you need to shock the pool. Do not attempt to do it with the SWG. Do it with Clorox and understand that shocking is a process that may take a fewe days....it is not a one time dosage. Read more about how to shock your pool in Pool School.

    Once you complete the shock process, your spots will be gone and your pool will be free of algae. You will also be able to turn down your SWG significantly.

    Again, do not try to use the SWG to shock.....use Clorox.

    At the same time, purchase and add enough CYA to your pool to get it to around 50-60ppm. That will help reduce your FC usage as well.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    frustratedpoolmom's Avatar
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    SWSuburban Chicago, IL
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    Re: FC and CYA WAY off???

    Please read Water Balance for SWG'sin Pool School - you need your CYA at 70-80 for your SWG to operate properly.

    If the "spots" are black algae or another type of organic algae, holding a trichlor tablet on the spot will make them fade, confirming they are organic in nature. If they are Black Algae, you need to brush your pool while at shock level to destroy the tough outer shell.

    Dave is right, do not try to shock your pool with your Cell, it shortens the life of the cell. Use liquid chlorine a.k.a. bleach.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    May 2008
    Location
    SE Texas
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    Re: FC and CYA WAY off???

    Thanks for the info.

    I've added stabilizer, liquid bleach and chlorine tablets to my skimmer.
    18x36 Gunite w/7' spa, Whisper Flow 2HP Pump FNS DE 60 sq.ft Filter, Letro Jet Vac, Minimax Heater 400,000 BTU, Goldline Aquarite

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    frustratedpoolmom's Avatar
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    Re: FC and CYA WAY off???

    Do not add tablets to a skimmer unless the filter/pump runs 24/7.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  6. Back To Top    #6

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    Location
    SE Texas
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    Re: FC and CYA WAY off???

    Oops, although I have been running it constant since I've put the tablets.

    My pool company use to do this all the time. Why shouldn't this be done?
    18x36 Gunite w/7' spa, Whisper Flow 2HP Pump FNS DE 60 sq.ft Filter, Letro Jet Vac, Minimax Heater 400,000 BTU, Goldline Aquarite

  7. Back To Top    #7
    Butterfly's Avatar
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    Re: FC and CYA WAY off???

    Quote Originally Posted by plumin
    Oops, although I have been running it constant since I've put the tablets.

    My pool company use to do this all the time. Why shouldn't this be done?
    Generally, because tablets are acidic and lower pH. This can be harmful to the skimmer parts causing them to become brittle and break easily, and it can wreak havoc on pump/filter/heater parts. Keep them in the chlorinator or in a floater, not the skimmer.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

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