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Thread: High temps eating chlorine?

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    High temps eating chlorine?

    Do high water temperatures cause chlorine to be used up quicker? My inground has been rather stable this year, but lately the chlorine has dipped rather low. With our auto safety cover on all the time, the SWG was only on 20% and it maintained the chlorine level around 6 without any problems. Lately, the chlorine level has been declining with each test (every few days). Yesterday evening it dipped to it's lowest of 2. I added about 80 oz of 6% bleach and turned the SWG up to 75% and let it run all night. This morning I tested and it was up to 3. With my CYA level, I like it to be around 5, so I'll be adding more bleach today to get it back up, but is it the heat that's causing this? The water has been around 91-93 degrees for the last two weeks which is really when it started the steady decline. I typically run the pump for 9 hours with the SWG at 20% and that was plenty. As I said it ran 9 hours yesterday and then I turned it back on last night at 11pm when I added the bleach and ran these tests this morning at 6:30.

    FC: 3
    CC: .5
    TC: 3.5
    pH: 7.2 (just recently dipped from 7.4 - I'll bring that back up later today also)
    CH: 110
    TA: 110
    CYA: 75

    Note: Our auto cover is closed unless we are in it, so it doesn't get much full sun.

    Thanks
    20x40 IG 30,000 Gal Vinyl
    Hayward 1HP Super Pump, Hayward Perflex D.E. filter, Hayward Universal H-Series 300K BTU heater, Hayward Aqua Rite SWG
    Hayward ColorLogic 4.0 LED Light
    Inter-fab X-Stream slide, Inter-fab Techni-Spring diving board
    APC Auto Safety Cover

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    dmanb2b's Avatar
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    Re: High temps eating chlorine?

    To rule out organics perform the overnight FC loss test. With CYA at 75, the SWG should be able to keep up, even in high heat especially if you use a cover.

    pool-school/overnight_fc_test
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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    Richard320's Avatar
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    Re: High temps eating chlorine?

    Survey says yes. Why, I don't know. Chlorine degrades faster in higher temperatures, even just sitting in the jug. Plus if there's anything growing in the pool, even tiny amounts you can't see, it will grow faster in the warmth. Below 50, algae hardly grows at all, but when it warms up, look out!
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    hawkeye's Avatar
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    Re: High temps eating chlorine?

    yes warm water will in fact use more chlorine,if you test your cya and know its at or real close to 50 you just need to stay on top of the chlorine, know that minimun fc is 4ppm and test daily....
    18ft 52in deep doughboy 8000 gallons
    22 in sand filter
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    tk-2006 test kit that rocks!
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    Re: High temps eating chlorine?

    I'll pull the FC back up to 5 this evening and then do an overnight test to see what's going on. Sounds like I should either increase my pump time or increase the percentage on the SWG (or both) during periods when the water temp is high.
    Thanks
    20x40 IG 30,000 Gal Vinyl
    Hayward 1HP Super Pump, Hayward Perflex D.E. filter, Hayward Universal H-Series 300K BTU heater, Hayward Aqua Rite SWG
    Hayward ColorLogic 4.0 LED Light
    Inter-fab X-Stream slide, Inter-fab Techni-Spring diving board
    APC Auto Safety Cover

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    Re: High temps eating chlorine?

    any chance your bleach is old? Been storing it in the heat too long?

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    Re: High temps eating chlorine?

    Quote Originally Posted by hayabusa3
    any chance your bleach is old? Been storing it in the heat too long?
    I don't use bleach. I have a SWG. I only added some last night to bring it up to 3ppm because I was nervous with it being at 2. I'm buying fresh bleach today to bring it the rest of the way back up to 5 (or slightly higher). The bleach I added last night was several months old, but it's been stored in the house (not the heat).
    20x40 IG 30,000 Gal Vinyl
    Hayward 1HP Super Pump, Hayward Perflex D.E. filter, Hayward Universal H-Series 300K BTU heater, Hayward Aqua Rite SWG
    Hayward ColorLogic 4.0 LED Light
    Inter-fab X-Stream slide, Inter-fab Techni-Spring diving board
    APC Auto Safety Cover

  8. Back To Top    #8

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    Re: High temps eating chlorine?

    On Friday evening I got the FC back up to 7 when I tested at 11pm. I tested the next morning at 6:30 and it was still 7, so I guess that means I'm OK. Checked the level again yesterday (Sunday) afternoon after being in the pool most of the day and the level was back down to 5. I added more bleach to get it back up. Should I need to be supplementing bleach if I have this SWG? Is it only because of the high temps lately? The water is still in the low 90s. I bumped the SWG up and increased my pump run time by an hour (10 hours now). Nobody will be in the pool today and the cover will be on all day. I'll check it this evening and see how the level is.
    20x40 IG 30,000 Gal Vinyl
    Hayward 1HP Super Pump, Hayward Perflex D.E. filter, Hayward Universal H-Series 300K BTU heater, Hayward Aqua Rite SWG
    Hayward ColorLogic 4.0 LED Light
    Inter-fab X-Stream slide, Inter-fab Techni-Spring diving board
    APC Auto Safety Cover

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    dmanb2b's Avatar
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    Re: High temps eating chlorine?

    Something else is odd here. Is the SWG throwing any error codes during it's run time? With CYA at 75, you should not be losing FC with the SWG running, as long as it is properly sized and is in fact making chlorine
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

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    linen's Avatar
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    Re: High temps eating chlorine?

    Quote Originally Posted by mrshanes
    On Friday evening I got the FC back up to 7 when I tested at 11pm. I tested the next morning at 6:30 and it was still 7, so I guess that means I'm OK.
    Did you turn off the SWG while you did the OCLT?
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: High temps eating chlorine?

    Quote Originally Posted by linen
    Quote Originally Posted by mrshanes
    On Friday evening I got the FC back up to 7 when I tested at 11pm. I tested the next morning at 6:30 and it was still 7, so I guess that means I'm OK.
    Did you turn off the SWG while you did the OCLT?
    Yes, the SWG was off all night.
    20x40 IG 30,000 Gal Vinyl
    Hayward 1HP Super Pump, Hayward Perflex D.E. filter, Hayward Universal H-Series 300K BTU heater, Hayward Aqua Rite SWG
    Hayward ColorLogic 4.0 LED Light
    Inter-fab X-Stream slide, Inter-fab Techni-Spring diving board
    APC Auto Safety Cover

  12. Back To Top    #12

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    Re: High temps eating chlorine?

    Quote Originally Posted by dmanb2b
    Something else is odd here. Is the SWG throwing any error codes during it's run time? With CYA at 75, you should not be losing FC with the SWG running, as long as it is properly sized and is in fact making chlorine
    I believe it's properly sized. It's the Aqua Rite SWG with the 40,000 gallon cell. I had to actually turn it way back earlier in the summer in order to get my chlorine down to a decent level. There are no error codes displayed and everything seems to be working fine. The cover was on all day yesterday and nobody was swimming. I checked last night around 8pm and the fc was 8, so it seemed to be OK. I'll continue to monitor the levels closely. I've been reading some posts on here about taking the cell out to clean and check to see if it's producing. I may do that if things continue to seem weird. But, it's only been in use for 3 months. Should it really need cleaned already?
    20x40 IG 30,000 Gal Vinyl
    Hayward 1HP Super Pump, Hayward Perflex D.E. filter, Hayward Universal H-Series 300K BTU heater, Hayward Aqua Rite SWG
    Hayward ColorLogic 4.0 LED Light
    Inter-fab X-Stream slide, Inter-fab Techni-Spring diving board
    APC Auto Safety Cover

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    pepsiholic's Avatar
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    Re: High temps eating chlorine?

    I really can't help you because I know nothing about SWG's, but I just wanted to say Hi, neighbor!
    24 x 52 Round AG Outback Empire Pool 13,500 gal.
    1 HP Hayward Power-Flo pump w/Hayward 18" 150lb. sand filter
    TF-100 test kit & SpeedStir
    Wanda the Whale Vacuum

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