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Thread: Safe FC range for swimming

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    Join Date
    Apr 2014
    Location
    Albuquerque, New Mexico
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    6

    Safe FC range for swimming

    Good day all,

    Can you please tell me if a safe swimming range for FC would be between 4-12ppm? Here is the reason I ask...

    The pool store tells me my CYA is at 80. My (inexperienced) testing with TFT-100 shows CYA in the 35-50 range and DEFINATELY NOT 80. I shocked the pool a few weeks back to a level of about FC 36 (for 2 days) and have kept it no lower than 6 or 7. I've been using on average 1.5 bottles of 121 oz 8.25% bleach every day. I hope this is a normal rate for my pool. The water looks crystal clear. My only issue is what I believe to be metal related yellow on deep bottom end of pool (by the way, I don't have a lot of metal in the pool but it has been like this since I opened it a couple months back). I continue to brush the pool and added only 1 gallon of Natural Chemistry Instant Water Conditioner when I first opened the pool. I suspect a safe swimming FC range would be 4-12 based on the Chlorine/CYA chart. Any thoughts? Thank you.

    Oval In-ground 16x29 / 25,000 gallon (estimated) gunite pool with 3/4 HP pump,
    Anthony "Apollo" DE filter, Keepy Krauly Cleaner and TF-100 Test Kit.

  2. Back To Top    #2

    Join Date
    Jul 2012
    Location
    Herndon, VA
    Posts
    419

    Re: Safe FC range for swimming

    Anything below shock level is fine....so if it was in fact cya 35, you could swim in FC up to about 14.
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

  3. Back To Top    #3
    Mod Squad tim5055's Avatar
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    May 2014
    Location
    Columbia, SC
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    8,495

    Re: Safe FC range for swimming

    I would suggest an Overnight FC Loss Test (OCLT). I know it's a lot sunnier out in NM, but my similar sized pool consumes less than 1/2 bottle of 121 oz 8.25% bleach every day.

    It just seems to be a lot of chlorine usage to me.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Join Date
    Oct 2013
    Location
    Chapin, SC
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    1,141

    Re: Safe FC range for swimming

    Me too! A half jug was my usage last summer too. I bought 4 jugs a week or so ago--just in case-- haven't used a drop yet! I love my swg!
    Pool size: 24000gal inground Vinyl-Taylor k-2006 and k-1766 test kits and-speed stir
    Intermatic P1353ME digital timer w/freeze sensor
    CircuPool Si-45 SWCG System
    Polaris 280 vacuum/Polaris PB4-60 boost pump
    Pentair IntelliFlo VS 3hp Pump--Pentair sand filter

  5. Back To Top    #5
    Butterfly's Avatar
    Join Date
    May 2007
    Location
    South Carolina
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    10,045

    Re: Safe FC range for swimming

    Hi Ray

    Yep, an OCLT would rule in/out organics. Tonight, I suggest you take it up to SLAM FC level, based on 50 CYA.

    It could just be that the CYA is closer to 35, but more testing is needed.
    Have you seen the CYA test video? Link in my sig. Remember you need to perform it in the daytime with the sun at your back and the tube about waist high.

    Have you tested the yellow stain with a cheap vitamin c tablet to determine if it is metals?

    What did you add to the pool before the deep end stained yellow?

    Do you use well water or municipal water to top-off your pool?
    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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  6. Back To Top    #6

    Join Date
    Apr 2014
    Location
    Albuquerque, New Mexico
    Posts
    6

    Re: Safe FC range for swimming

    Thanks for all your comments. As I stated initially, I did bring the pool up to FC 36 (during the SLAM) for a couple days based on a CYA of 80 (and the OCLT was 1 or less overnight). I've since kept the pool at FC 7-14. The temperature here has been in the 90s for like 5 weeks. The CYA level seems the most tricky especially since it has been so hot outside. And yes, I have seen the CYA test video. I was just wondering if I could get more of an idea of my CYA level based on how much bleach I was adding to the pool daily. I'd really hate to add more stabilizer to my pool if it really is at the 80 level (highly doubtful based on my test). However, maybe it doesn't have enough since I still seem to be using a lot of bleach. I'll go ahead and rub a vitamin c tablet on the stain. The water does come from the city and is not well water. Also, the stain has been there since I opened the pool (along with some chipped pieces of tile from the waterline). I think the gallon bottle of 1 Natural Chemistry Instant Water Conditioner at the start of season only added 13.3ppm CYA to my 25K gallon pool. I hope I calculated that correctly.
    Oval In-ground 16x29 / 25,000 gallon (estimated) gunite pool with 3/4 HP pump,
    Anthony "Apollo" DE filter, Keepy Krauly Cleaner and TF-100 Test Kit.

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