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Thread: Why can't I keep FC in normal range?

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    Why can't I keep FC in normal range?

    Hi all. New pool owner doing pretty well with BBB method. My only concern is my FC. I add chlorine every evening. I test it in the morning before work and it's perfect. I get home 10 hours later and my FC is like 1. Here's all my test results:

    This morning:
    FC 4
    TA 90
    Ph 7.6
    CYA 40
    CH - didn't test

    I need to tell you guys that I live in VA and it is very hot. My pool sits in the sun from sunrise to roughly 6pm. My cya seems ok, or I thought so. So how do I keep chlorine in the pool?
    Also, I run my pump all day and for 3 hours after I add chemicals. I turn it off at night. Is this wrong?

    Please help.

    Hayward 15x30 4ft deep above ground oval, hayward dreamline sand filter with hayward powerflo lx pump 1hp, BBB method, lil' shark cleaner

  2. Back To Top    #2

    Join Date
    Feb 2008
    Flower Mound, TX

    Re: Why can't I keep FC in normal range?

    What is your CC?

    So, your FC is exactly the same in the morning as it was when you went to bed the night before?

    If you are one that gets lots of direct sun on the water, you may need to up your CYA a bit. I would like to be sure that you aren't losing FC to organics in the water first.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  3. Back To Top    #3

    Re: Why can't I keep FC in normal range?

    so you are using about 3 ppm per day of chlorine, a little high but thats about what my pool
    uses as it is in the sun all day. so if you are consistently losing 3 ppm per day, you need to start
    the day a little higher. i raise mine to about 6 ppm every evening and that way i never go below
    3 ppm the next day. getting down to 1 ppm with 40 cya is asking for trouble.
    24,000 gallon ig fiberglass pool
    1 hp hayward pump
    hayward sand filter (250 lb)
    madisonville, ky

  4. Back To Top    #4
    Butterfly's Avatar
    Join Date
    May 2007
    South Carolina

    Re: Why can't I keep FC in normal range?

    You should do an overnight FC loss test to rule out organics.

    If you pass the test, then you should consider raising your CYA to about 50.
    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.

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  5. Back To Top    #5
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    East Texas

    Re: Why can't I keep FC in normal range?

    I bump my target FC to 2ppm over what the chart says for a cushion. I lose 3-4ppm per day, all day sun. Taking CYA to 60 or so myself. and 70 if that doesn't work!
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  6. Back To Top    #6

    Join Date
    Oct 2010
    Houston, TX

    Re: Why can't I keep FC in normal range?

    I (un)fortunately have a separate spa and pool so I have to maintain 2 bodies of water. On the pool, was losing 2-3ppm, and the spa, 3-4ppm per day; CYA was 70 on both, FC overnight loss test 0, LOTS of sun on both each day (more so on the spa).

    So, no, not out of the question for FC to do that in sunny hot climates; important to do the FC overnight test to make sure there are no organics causing the FC drop first, and if that's ok, bump up CYA like others have mentioned.

    But the thing that really helped me was to get a salt water generator for the pool (best thing I did; well, that and borates). And I put a solar cover on the spa which cut the loss of FC from 3-4 per day to 1.5-2 per day, and life got much easier (couldn't put a SWG on the spa due to flagstone waterfall).

    Only have had the SWG a few weeks, but life is SO much better not worrying about lugging chlorine and adding it and worrying about FC drop. Now the only thing I need now is the Margaritaville frozen concoction maker that woodyp has...
    15k gunite pool. Intelliflo VF. Autopilot SWG.
    2k separate spa with waterfall (ie: pain in the rear maintaining a separate body of water). 2HP Hayward Tristar pump.

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