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Thread: Is it unusual

  1. Back To Top    #1

    Is it unusual

    to loose 6FC's from 6:15am to 7:30pm?

    I checked my FC at 6:15am yesterday morning, cause I was letting the nunbers come down from shocking it at 15FC, and it was 14.0 from 14.5 the night before....I get home at 7pm and check it again, and it's at 8FC...

    I know the children were playing in the pool and it was very hot, almost 100 degrees, but is it unusual for the FC's to drop that much in a 13 hour period?
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  2. Back To Top    #2
    oh, forgot to add

    my other numbers are consistent...

    PH at 7.4 and alk at 140, and CYA at 35
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  3. Back To Top    #3
    What is your CYA level?

  4. Back To Top    #4
    Quote Originally Posted by Rangeball
    What is your CYA level?
    35
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  5. Back To Top    #5
    Mod Squad JohnT's Avatar
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    A lot of things can do that. Low CYA is one thing that will hurt by allowing the sun to degrade the chlorine. Kids peeing in the pool is another thing that uses a lot of chlorine.
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  6. Back To Top    #6
    Quote Originally Posted by JohnT
    A lot of things can do that. Low CYA is one thing that will hurt by allowing the sun to degrade the chlorine. Kids peeing in the pool is another thing that uses a lot of chlorine.
    well it's not the cya, it's at 35, and my children are told not to pee in the pool and hopefully their not.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  7. Back To Top    #7
    For a CYA of 35 ppm the target FC is 4 ppm. I suspect any TC above this amount isn't well protected from CYA and as such is vulnerable to being lost during daylight.

  8. Back To Top    #8
    JasonLion's Avatar
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    Losing 50% of your FC level across an entire sunny day with a CYA level of 35 is normal. Typically you would start with a much lower FC level and so lose less chlorine each day, but given that you started at 14 and assuming it was an average sunny day that sounds quite normal.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  9. Back To Top    #9
    Quote Originally Posted by JasonLion
    Losing 50% of your FC level across an entire sunny day with a CYA level of 35 is normal. Typically you would start with a much lower FC level and so lose less chlorine each day, but given that you started at 14 and assuming it was an average sunny day that sounds quite normal.
    but I guess my problem is maintaining that 3 to 6 level everyday.....

    if I check it at 6:15am every morning and say it's at the high end 6FC, by the time I get home, even if no one was swimming in the pool, it could possibly go down to 2, which it has. Last Saturday we were away, and I was unable to monitor the entire day, and when we left, the FC level was at 6, I believe, and by the time we got home that night, it was at 2.5 and the CC went up to 1.0, that's the reason I shocked it Sunday night and was letting it drift back to 6.

    I'm just afraid if it's at 6 at 6:15am, and I get home at around 6pm that night, it'll be below the 3FC level and CC's will be up and I'll be shocking every other day.

    It was at 8 this morning, and I'll have my wife check it at around 2pm today.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  10. Back To Top    #10
    JasonLion's Avatar
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    Losing 2/3rds of your chlorine across one day is a little high but not implausible, particuarly if it is very sunny and someone is swimming in the pool. I wouldn't normally expect CC to go to 1 without several people swimming or algae or a particuarly high level of pollen or other organic debris getting into the pool.

    There are two approachs to this. You can either start each day with a higher chlorine level, so that it is still 3 ppm in the evening. Or you can increase your CYA level somewhat, perhaps to 60, so that you lose less to sunlight. Because of the CC, I wonder if your issues might be more with swimmers, and possible "accidents", than with sunlight.
    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

  11. Back To Top    #11
    I think it might also be what we believe to be pollen from the outer branches of a tree, which I have to vacuum up from the bottom of the pool every other day.

    so, that might be the culprit also.

    I might have to just start out at like 8 everyday, or since the pool is taken down around September of every year, I might do what you suggested, raise the CYA to 60 so it protects more of the chlorine. And, since the pool is taken down every year, I'm not concerned too much with the CYA drifting upward since I watch it and never use pucks or anything, just the BBB method.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  12. Back To Top    #12
    rpgman, what kind of pool is it?

    Is it possible to use a cover?

  13. Back To Top    #13
    Quote Originally Posted by Rangeball
    rpgman, what kind of pool is it?

    Is it possible to use a cover?
    it's an AG Intex Metal Frame 18x48 6280 gallon pool....

    I have a cover for it, but it's kind of a hassle to get my wife out there helping me put a cover on it when it's not in use, and her having to do it by herself if I'm at work.....

    I thought about that, but putting the cover on and off is a real hassle....we usually only use a cover if we know a strong storm is coming or we're away for an extended period of time.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  14. Back To Top    #14
    I was thinking as a test, if you find a day when no one will be swimming, to test the pool in the am, cover the pool then test that night.

  15. Back To Top    #15
    Quote Originally Posted by Rangeball
    I was thinking as a test, if you find a day when no one will be swimming, to test the pool in the am, cover the pool then test that night.
    oh, sure, I'll try that this weekend, if the conditions are going to be the same, sunny, hot during the day.

    btw, I voted on your poll.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  16. Back To Top    #16
    as of 2pm it's down to 6.0ppm FC from 8.0ppm as of 5:45am this morning. With no one swimming and about mid 90's and sunny here today.

    so, it's the combination of pollen in the pool, and sunlight, I guess.

    should be down to 4 by the time I get home at 6:15pm tonight, and I'll adjust it back up to 8 again.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  17. Back To Top    #17
    Mod Squad JohnT's Avatar
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    Is your water clear? Any cloudiness can make the CYA test read high.
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  18. Back To Top    #18
    Quote Originally Posted by JohnT
    Is your water clear? Any cloudiness can make the CYA test read high.
    yep, sparkling clear, can see right to the bottom, but it's only 48 inches.....

    plus, 2 weeks ago when I put the pool up, I added 1.75 pounds of stabilizer, which should have brought me up to the 35 cya range on a 6280 gallon pool. Which I believe it did overnight.....it dissolved very quickly through the skimmer basket.

    But, I'm using a 1/2 hp Hayward sand filter,which might be overkill for the pool, but it'll flow my water in about 1 1/2 to 2 hours, so maybe that's the reason it dissolved so quickly.
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

  19. Back To Top    #19
    With only 48' of depth to work with, you aren't getting as much protection from UV as you would with a deeper pool.

    Plus, you mention 100* days, are you in a souther latitude? Higher temps plus higher UV based on your location might be a double whammy.

    Others in similar situations have reported taking their CYA up as high as 80 and finding much better chlorine protection. Something you might want to consider, possibly.

  20. Back To Top    #20
    Quote Originally Posted by Rangeball
    With only 48' of depth to work with, you aren't getting as much protection from UV as you would with a deeper pool.

    Plus, you mention 100* days, are you in a souther latitude? Higher temps plus higher UV based on your location might be a double whammy.

    Others in similar situations have reported taking their CYA up as high as 80 and finding much better chlorine protection. Something you might want to consider, possibly.
    yea, in Florence , South Carolina, it's 90 today here with a UV index of 9 (Very High).
    14 x 32 x 6 (ave depth) 20K gallons - IG gunite pool. Challenger 1.5 hp pump and cartridge filter.

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