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Thread: FC went from 7 to 0

  1. Back To Top    #1

    Join Date
    Aug 2016
    Location
    Merrick NY
    Posts
    10

    FC went from 7 to 0

    I used my TF-100 new two days ago. results were as follows:

    TC 2.5
    CC 0
    PH 7.5
    CH 220
    CYA 75
    Salt 2500
    Borate 15

    I added 2 gallons of bleach as per the pool calc and tested it yesterday morning and FC came up to 7. Later that night I added 5 bags of salt. I tested 24 hours later and my FC is 0.5 CC 0.5. Any ideas how I lost so much FC with a CYA of 75?

    What to do next?

    Thanks.
    33k gal, SWG vinyl IGP, free form lagoon, 8' deep end 4' shallow end, Pentair IntelliFlo VS 2hp, AutoPilot SWG, DE filter, Manifold with RC-35/22 cell, Pool Pilot Digital, Gas heater, waterfall, 7 wall returns, 2 bottom returns, 2 skimmer baskets

  2. Back To Top    #2
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: FC went from 7 to 0

    Try an overnight chlorine loss test to see if you have something growing in your pool.

    Pool School - Perform the Overnight FC Loss Test (OCLT)
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

  3. Back To Top    #3

    Join Date
    Aug 2016
    Location
    Merrick NY
    Posts
    10

    Re: FC went from 7 to 0

    Thanks. I did o an oclt about 5 days ago and it was ok. Should I bring up the FC back to 6 first?
    33k gal, SWG vinyl IGP, free form lagoon, 8' deep end 4' shallow end, Pentair IntelliFlo VS 2hp, AutoPilot SWG, DE filter, Manifold with RC-35/22 cell, Pool Pilot Digital, Gas heater, waterfall, 7 wall returns, 2 bottom returns, 2 skimmer baskets

  4. Back To Top    #4
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,968

    Re: FC went from 7 to 0

    You mentioned that you did the OCLT about 5 days ago, but you just got your TF-100 a couple days ago. With a CYA of 75 (round-up to 80) in a SWG pool, your daily FC level is 6 ppm and should never be below 4. Your FC was so low before it's very possible you have algae trying to bloom which is why Isaac-1 suggested a new OCLT. If you still find your FC crashing so much in a 24 hour period, it's probably time to do a TFP "SLAM" (link below).
    Pool School - Perform the Overnight FC Loss Test (OCLT)
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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