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Thread: My FC did drop

  1. Back To Top    #1

    My FC did drop

    5/30
    FC 13
    CC .5
    TC 13.5
    TA 170

    After changing the SWG from 3 hours to 2 hours last night, today the results were
    FC 8
    CC .5
    TC 8.5
    TA 150
    pH same - between 7.2 and 7.5 but the color is much closer to 7.5

    FC dropped significantly by dropping the hour on SWG didn't it? I still need it to get to 5 though. I hope it doesn't keep dropping that quickly or I'll be in trouble. I'll just wait and see when I test tomorrow before panicking.
    Intex 20'x10'x52" 5,835 gallon above ground; vinyl; Intex 2,650-Gallon Sand Filter Pump; Intex Krystal Clear Saltwater System Model CS8110.

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,887

    Re: My FC did drop

    When adjusting the SWG run time, it is best to test the FC level in the early evening. That is when FC is the lowest, which is what matters.
    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

  3. Back To Top    #3

    Re: My FC did drop

    Thank you. I guess I missed that. I will retest this evening. Should I just test everything in the evening or do some tests need to be done in the morning? Thank you for your insight.
    Intex 20'x10'x52" 5,835 gallon above ground; vinyl; Intex 2,650-Gallon Sand Filter Pump; Intex Krystal Clear Saltwater System Model CS8110.

  4. Back To Top    #4

    Join Date
    Jan 2009
    Location
    Cupertino, CA
    Posts
    1,966

    Re: My FC did drop

    Most people find it convenient to test whatever they need to test all at the same time.

    Do you run the SWG at night, or during the day? If you run it during the day, then FC will be lowest just before it comes on, and that would be the time to test FC. Otherwise evening after the sun is off the pool (and before the SWG comes on) is best.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

  5. Back To Top    #5

    Re: My FC did drop

    Thank you very much. The SWG comes on at 9 pm. I live in So CA and in one of those areas where we hit 115-120 in our hottest time in August so I don't run anything if possible during the day except A/C. Maybe it would be best to test about 7:30 while I still have light but before SWG comes on. Thank you.
    Intex 20'x10'x52" 5,835 gallon above ground; vinyl; Intex 2,650-Gallon Sand Filter Pump; Intex Krystal Clear Saltwater System Model CS8110.

  6. Back To Top    #6

    Join Date
    Jan 2009
    Location
    Cupertino, CA
    Posts
    1,966

    Re: My FC did drop

    Quote Originally Posted by imcj
    Maybe it would be best to test about 7:30 while I still have light but before SWG comes on.
    My only caution is if you need to test CYA, that should be done with your back to full sun to get the right light level. Otherwise you should be fine.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

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