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Thread: FC loss in 24hrs

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    FC loss in 24hrs

    I'm just curious if anyone could give me some average numbers on their FC PPM loss over a day. Preferably some southerners, our pool hits 90 degrees during the day lately with alot of sunshine. I just got done clearing the pool from a dash of algea, I cought it quickly and got on top of it fast. Yesterday I went without the swg during the day for 12hrs to start bringing the FC down and I lost 5ppm, just wondering if this is about right.
    Noob Here!
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    reebok's Avatar
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    Re: FC loss in 24hrs

    2ppm is the going rate. it can vary. are you sure you got all the algae? did you do an overnight fc loss test?
    pool-school/overnight_fc_test
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

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    Re: FC loss in 24hrs

    Yes, thats when I stopped the shock.
    My #'s this morning.
    FC - 16.5
    CC - 0
    TA - 80
    CYA- 65 added some this morning, had a leak up till last week, might still have a smaller one.
    Salt - 3100
    Noob Here!
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    duraleigh's Avatar
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    Re: FC loss in 24hrs

    5ppm in a days time is pretty far above average, even for your Southern conditions.

    I would suggest letting the FC go back down to normal for a day or so and then do another overnite FC loss test.

    Remember, only two things consume chlorine.....sunlight and organics (usually algae).
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: FC loss in 24hrs

    I'll try that.
    Noob Here!
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    mas985's Avatar
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    Re: FC loss in 24hrs

    Quote Originally Posted by newnick
    Yes, thats when I stopped the shock.
    My #'s this morning.
    FC - 16.5
    CC - 0
    TA - 80
    CYA- 65 added some this morning, had a leak up till last week, might still have a smaller one.
    Salt - 3100
    Losing 5 ppm out of 16 ppm is only about 30% extinction which is about what I see at a CYA of 65 ppm. So I think what you are seeing is reasonable.
    Mark
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    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: FC loss in 24hrs

    Over Friday night I lost close to 1ppm. From 20 to 19
    Left the swg off another 12 hrs, 24 hrs total, dropped to 14.
    So I guess I'm closer to 25% than 30%, does that sound right?
    Noob Here!
    24' Above Ground
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    Re: FC loss in 24hrs

    A week has gone by now, been running 24/7 and trimming back the swg.
    Numbers this morning after shutting down the pump over night.
    FC 11.5 Lost .5 overnight
    CC 0
    PH 7.6
    TA 80
    CYA 80

    I've trimmed the swg back to 25 percent through the week running 24/7 easing the FC down. I'd like to go back to 12on/12off to cut back on electicity. If running at 25 percent was working 24on/0 off can I go to 50 percent and run a 12/12 schedule and be close to the same amount of chlorine production?
    Noob Here!
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    Woodberg's Avatar
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    Re: FC loss in 24hrs

    I'm in Houston and we are also averaging about 4ppm FC usage each day. I've down the nightime test and the FC is holding steady overnight. I just think its the intense heat right now. During the spring I was averaging around 2PPM FC usage each day.
    20,000 gallon gunite pool, attached spa, Pebblesheen finish, Paramount PCC-2000 infloor cleaning system, Paramount ClearO3 ozone system, Intelliflo VS main pump, Whisperflo 1HP cleaner pump, StaRite cartridge filter, StaRite heater

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    Re: FC loss in 24hrs

    We had a couple of what I'll call intensely boggy days a couple weeks ago where we were losing 5 to 6 ppm per day.
    I guess I'd describe boggy as stale heavy feeling air.

    Since then it's been hotter and even more humid some days but loss has been only 2 to 3 ppm over 24 hours.
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    Re: FC loss in 24hrs

    I'm on the Gulf Coast and our pool water temperature is 92 F right now. My target FC is 4.0 and I have been losing a constant 1.5 - 2.0 ppm chlorine every 24 hours since March. In fact it's been amazingly constant. The water has stayed clear as clean glass. I have to add about 2 or 3 cups of acid once a month to keep the pH down and I've had to add ten pounds of baking soda to bring the TA up and that's all I've done since late February. I have not even had to backwash the filter since (I believe) the 1st of May.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Stenner 45 MPH10 chlorine feed pump. 1 micron final filter bags (home made and very effective)

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    Re: FC loss in 24hrs

    Do ya'll run your pumps 24/7 ?
    Are there any trees close to your pools?
    Noob Here!
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    Re: FC loss in 24hrs

    I run my pump 12 hours per day 7 days per week from 8 am to 8pm. And yes, I have a ton of trees around my pool, live oak, hickory, dog wood, Chinese cotton ball, maple, and a little further away lots of pine. There is also a creek that runs into a swamp just outside my back fence. The pool gets full sun from about 9 am until about 5:30 pm (if I keep the trees trimmed).
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Stenner 45 MPH10 chlorine feed pump. 1 micron final filter bags (home made and very effective)

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    Re: FC loss in 24hrs

    Quote Originally Posted by stev32k
    I'm on the Gulf Coast and our pool water temperature is 92 F right now. My target FC is 4.0 and I have been losing a constant 1.5 - 2.0 ppm chlorine every 24 hours since March. In fact it's been amazingly constant. The water has stayed clear as clean glass. I have to add about 2 or 3 cups of acid once a month to keep the pH down and I've had to add ten pounds of baking soda to bring the TA up and that's all I've done since late February. I have not even had to backwash the filter since (I believe) the 1st of May.
    Have you considered running your pool at a lower TA level since that may reduce the rate of pH rise letting you use less acid and baking soda? What is your current TA level?
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: FC loss in 24hrs

    Outside temp has been an average of 95 with a pool temp of 91.
    I have been using anywhere from 3.5-7ppm in a 24 hour period lately; it depends on how much the kids swim and how many go swimming.
    27' round AG vinyl, 54" height with 18,200 gallons of water.
    1HP pump, 150lb sand filter run 12-14 per day. Using 12.5% liquid chlorine. BBB method.
    Taylor K-2006 test kit. Lamotte strips for borate at 50ppm.
    Goals: CYA-40, TA-80, FC-4, CC-0, Borate-50, PH-7.4-7.8 with use of fountain.

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    Re: FC loss in 24hrs

    Quote Originally Posted by chem geek
    Quote Originally Posted by stev32k
    I'm on the Gulf Coast and our pool water temperature is 92 F right now. My target FC is 4.0 and I have been losing a constant 1.5 - 2.0 ppm chlorine every 24 hours since March. In fact it's been amazingly constant. The water has stayed clear as clean glass. I have to add about 2 or 3 cups of acid once a month to keep the pH down and I've had to add ten pounds of baking soda to bring the TA up and that's all I've done since late February. I have not even had to backwash the filter since (I believe) the 1st of May.
    Have you considered running your pool at a lower TA level since that may reduce the rate of pH rise letting you use less acid and baking soda? What is your current TA level?
    I maintain the TA between 50 & 90. My last TA test was 80 ppm. I'm pretty sure the pH rise is due to using the cheap wal-mart bleach. That brand has a large excess of sodium hydroxide. I've read (can't remember where) that it can have as much as 20% excess caustic.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Stenner 45 MPH10 chlorine feed pump. 1 micron final filter bags (home made and very effective)

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    Re: FC loss in 24hrs

    Quote Originally Posted by stev32k
    I've read (can't remember where) that it can have as much as 20% excess caustic.
    There's no way it's 20%. It could be 2% which would be high and yes, would contribute to rising pH. Clorox Regular unscented has very low "excess lye" in it -- around 0.25% -- so should have minimal pH rise compared to the off-brand bleach you are using. Or course, it's probably more expensive.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    frustratedpoolmom's Avatar
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    Re: FC loss in 24hrs

    Well, all pools are unique but I've been using Wal-mart bleach for over 2 years and my PH and TA don't budge.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
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    Re: FC loss in 24hrs

    Quote Originally Posted by chem geek
    Have you considered running your pool at a lower TA level since that may reduce the rate of pH rise letting you use less acid and baking soda? What is your current TA level?
    How low would you suggest? I have a very similar situation to stev32k. We are experiencing extreme heat and my pool temp is hovering around 92-93 degrees. My TA is currently at 80 and my PH is rising rapidly. I'm having to add acid every 1-2 days to keep it in check. We've been out of town for a few weeks this summer and I've used Trichlor tabs while away. Other than that I use bleach. What I've noticed is that the acidity of the tabs keeps my PH pretty constant. Also, we have a raised spa which cascades water down into the pool. I think the constant aeration is not helping the situation.

    I know there's not a definitive answer on where to set the TA, but if you could give me a best guess target to aim for I'd appreciate it.
    20,000 gallon gunite pool, attached spa, Pebblesheen finish, Paramount PCC-2000 infloor cleaning system, Paramount ClearO3 ozone system, Intelliflo VS main pump, Whisperflo 1HP cleaner pump, StaRite cartridge filter, StaRite heater

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    frustratedpoolmom's Avatar
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    Re: FC loss in 24hrs

    Try 60, if you have constant aeration. I wouldn't go lower.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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