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Thread: How to lower very high FC after successful slam?

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    How to lower very high FC after successful slam?

    I performed a successful SLAM of my SWG pool w/ CYA of 70 at the time which required FC of 28. Met all SLAM requirements and have not added any chlorine in 4 days and SWG is off. Current readings (k-2006) from this morning but unsure of reliability of #s given such high FC from SLAM:

    FC: 25.5 (it has been cloudy and rainy)
    CC: 0.5
    pH: 7.4
    TA: 60 (was 80)
    CH:250
    CYA:60 (was 70)
    Salt: 3000
    Temp: 86 degrees

    So four days after my SLAM success, pool looks great but my FC is still 25.5 and above shock level for my now lower CYA of 60. I'd like to swim in the pool this holiday weekend but have 1 day to lower it to safe levels. It is sunny today here in Houston. Do I wait like I normally would or add the Thiosulfate today?? If I add Thiosulfate, should I lower FC to 10?? 8?? Thank you so much!!
    Warren
    22,400 gallon pool / spa combo with Painted Plaster; 16' x 40' rectangular pool w/ 9' x 9' elevated spa w/ waterfall to pool; Pentair IntelliFlo Variable Speed Pump, Pentair 420 Cartridge Filter, Pentair 4000 BTU heater, Pentair Intellachlor SWG and Clear 03 Ozone System

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    duraleigh's Avatar
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    Re: How to lower very high FC after successful slam?

    Just leave it alone. It'll come down. I assume you shut off your SWG, right?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Pool Tool's Avatar
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    Re: How to lower very high FC after successful slam?

    Although leaving it alone would likely be fine, you could consider:
    - raising your CYA back up to 70, which would make the levels safe to swim.
    - soak all the pool toys, rafts, cover, etc. in the high FC water, which would clean them off and reduce the FC
    - if you didn't already, pull the light and clean the niche out

    Congrats on the successful slam.
    16' x 32' (21100 gal), vinyl, 1.5 hp Hayward SuperPump,
    Tagelus TA60/60D Sand Filter, Raypak 399K Digital Heater, TF-100

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    DaninFLA's Avatar
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    Re: How to lower very high FC after successful slam?

    you can lower the FC with hydrogen peroxide. but I wouldn't worry about it. your shock level for CYA of 60 is 24 and you are at 25.5 and have two more days. it will be lower by then. as long as its lower than shock level, no issues. I would get more CYA in there by the way
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: How to lower very high FC after successful slam?

    Thanks to everyone for the great replies. One last question. I have been reluctant to add CYA or baking soda to raise TA and CYA since the TFP site says that readings can be inaccurate at high levels of FC like mine. Is it now OK to add other chemicals, even with FC at 25.5??

    Thanks again!!
    Warren
    22,400 gallon pool / spa combo with Painted Plaster; 16' x 40' rectangular pool w/ 9' x 9' elevated spa w/ waterfall to pool; Pentair IntelliFlo Variable Speed Pump, Pentair 420 Cartridge Filter, Pentair 4000 BTU heater, Pentair Intellachlor SWG and Clear 03 Ozone System

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    Pool Tool's Avatar
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    Re: How to lower very high FC after successful slam?

    Generally ph is the only reading affected by high FC. Feel free to raise CYA and I would leave the TA right where it is.
    16' x 32' (21100 gal), vinyl, 1.5 hp Hayward SuperPump,
    Tagelus TA60/60D Sand Filter, Raypak 399K Digital Heater, TF-100

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