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Thread: How quickly can the Sun "eat" your Chlorine

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    How quickly can the Sun "eat" your Chlorine

    Hi guys

    Stinking hot in my part of the world (40'C in my language or over 100'F for my American friends) . It's also School holiday time which means the pool is getting a lot more use and the cover is off most of the day.

    What I wanted to get some feedback on is what would be considered "normal" for FC to potentially drop on a high use day? ie with high bather load and high sunshine?

    Reason I ask is yesterday my FC was 6ppm I tested today and I am at 3 ppm. As I say high use and the sun is beating down, but would that be considered normal to drop that amount in a day?

    These are my figures

    Ph 7.4
    CYA 70
    FC (yesterday morning 6ppm) after use all day and cover off FC today was 3ppm (I just added some Liquid Chlorine to give it a kick back up)

    Other than the 3ppm drop the water looks great. I am going to try dial up my SWG a notch or 2 to try and compensate but just wanted to get a feel if the above scenario would be considered normal or do I potentially have something more sinister to worry about?

    Cheers
    18000 L Vinyl Lined IG pool, Astral Viron P-300 3 speed Pump, Astral VX SWG, Astral 25" Sand Filter
    TF-100 test kit

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    Re: How quickly can the Sun "eat" your Chlorine

    Hiya Docker_Rob,

    Hot day isn't it in WA?, I've just posted a similar thread asking about this and when to SLAM, like you my FC has dropped from 6 - 3 in the last couple of days, with the high temp and frequent use like yourself, so its kinda confirmed to me given you have the same issue that I may need to dial up the SWG (currently 40%, to 50-60%), I've just added some chlorine to bring it back up now. My pool was bordering on cloudy with the drop in FC, going to keep an eye on it this afternoon!.

    I noticed in your signature you got the TF-100 to Perth, can I ask how? I'm awaiting mine using ShopMate

    Good to see another WA'er
    3yr old 60,000L (15.8k Gal) Fibreglass IG, Viron eVo P600 pump, Hayward Pro Series Filter (glass media), Zodiac SWG, Zodiac VX55 4WD, Solar Heated

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    Re: How quickly can the Sun "eat" your Chlorine

    When expecting a high bather-load, raise your FC above your target level for your CYA. Liquid chlorine/bleach is your friend in these situations.

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    Mod Squad tim5055's Avatar
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    Re: How quickly can the Sun "eat" your Chlorine

    Just to reassure you, 3ppm FC loss during the day is not unusual. Please remember that following our methods 3ppm FC with 70CYA in a SWG pool isthe absolute minimum. You may want to,target 7ppm to give a little "insurance" to make sure you don't go too low on the chlorine.
    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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    Re: How quickly can the Sun "eat" your Chlorine

    Keep a close eye on your numbers and your water clarity the next few days just to be safe.

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    Re: How quickly can the Sun "eat" your Chlorine

    Quote Originally Posted by Hawknz View Post
    Hiya Docker_Rob,

    I noticed in your signature you got the TF-100 to Perth, can I ask how? I'm awaiting mine using ShopMate
    Hi Hawknz, : Re the TF100 Kit. My wife was in the US for work and we ordered one shipped to the Hotel. Freight as you know is the kiiler for us

    Everyone else, thanks for the replies, gives me a bit of piece of mind. I was concerned I may have had an issue possibly even with a SWG cell on the way out of soemthing. All good and time to get back in the Pool before I melt!
    18000 L Vinyl Lined IG pool, Astral Viron P-300 3 speed Pump, Astral VX SWG, Astral 25" Sand Filter
    TF-100 test kit

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    Re: How quickly can the Sun "eat" your Chlorine

    Hi Guys,

    I am in exactly in the same boat and just trying to 'stay afloat' (pardon the pun) above the target range for my CYA of 80. I am topping up with a litre of liquid chlorine to take me up to about 8-9FC a couple above my target of 6. Everything going well so far.

    Best time to add the liquid chlorine is about 5pm when the heat of the sun comes off the pool. My pool is looking good though.

    I am running my SWG about 8 hours at 100% to keep up.

    Good tip-get a solar cover it makes a big difference to saving your FC during the heat of the day
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
    K-2006

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    Re: How quickly can the Sun "eat" your Chlorine

    Jezza: Arg! 100%? That's hard on your cell. Have you considered increasing your pump run time or supplementing more with chlorine?

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    Re: How quickly can the Sun "eat" your Chlorine

    Yes unfortunately was the SWG provided with the pool when it was installed- knowing what I do now I realise that it is way undersized for our hot summers. But our electricity prices here are horrendous- so the lesser of 2 evils I'm afraid although I do use the LQ to top up. I've accepted that I will eventually buy the oversized version next time.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
    K-2006

  10. Back To Top    #10

    Re: How quickly can the Sun "eat" your Chlorine

    Pool School - Perform the Overnight FC Loss Test (OCLT)

    This test can help determine if there is something besides the sun consuming the chlorine.

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    Re: How quickly can the Sun "eat" your Chlorine

    Quote Originally Posted by Docker_rob View Post

    <Snip>

    Other than the 3ppm drop the water looks great. I am going to try dial up my SWG a notch or 2 to try and compensate but just wanted to get a feel if the above scenario would be considered normal or do I potentially have something more sinister to worry about?

    Cheers
    Losing 3ppm per day, in that sort of heat and sunshine is not bad, actually. I would thank that, this year, you would be especially hard hit due to the size of the ozone hole.....

  12. Back To Top    #12

    Re: How quickly can the Sun "eat" your Chlorine

    3 ppm is not a lot under the conditions. However, if the swg was on during the time, then you lost 3 ppm in addition to whatever the swg produced. How much chlorine did the swg produce in the time period in question?

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    Re: How quickly can the Sun "eat" your Chlorine

    Quote Originally Posted by JamesW View Post
    3 ppm is not a lot under the conditions. However, if the swg was on during the time, then you lost 3 ppm in addition to whatever the swg produced. How much chlorine did the swg produce in the time period in question?
    Good point. Full test results would help. Some of your chlorine may show up as CC, due to the high bather load.....

  14. Back To Top    #14

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    Re: How quickly can the Sun "eat" your Chlorine

    How is the pool looking today?

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    Re: How quickly can the Sun "eat" your Chlorine

    Mine is fine. Again had to top up with a bit of liquid Chlorine but other than that all good.
    18000 L Vinyl Lined IG pool, Astral Viron P-300 3 speed Pump, Astral VX SWG, Astral 25" Sand Filter
    TF-100 test kit

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    Re: How quickly can the Sun "eat" your Chlorine

    Docker_rob

    Hi from Dallas, TX .

    My average daily FC depletion rate during the summer is between 2.25 - 3.0 .

    This is with an average summer (June-Aug) temp in Dallas between 34-37C.

    My CYA level is usually maintained between 30-40 .
    - Pool Type: 15k Gal Gunite IG non-SWG / Built 1988
    - Pump: Pentair Challenger / Sweep Pump: Letro Model LA01N .75HP Single-speed / 6 hrs-day (1 turnover)
    - D.E. Filter: OEM: Nautilus (Pentair) #NS 36 / 36 Sq Ft / D.E. Charge: 3.6 Lb
    - Pentair 4-wheel Sweep LL505G - Booster Pump runs ~2 hrs/day

  17. Back To Top    #17
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    Re: How quickly can the Sun "eat" your Chlorine

    Quote Originally Posted by Scoop View Post
    Docker_rob

    Hi from Dallas, TX .

    My average daily FC depletion rate during the summer is between 2.25 - 3.0 .

    This is with an average summer (June-Aug) temp in Dallas between 34-37C.

    My CYA level is usually maintained between 30-40 .
    About right for me in Pennsylvania, on a 90 day with full sun 12 hours a day.

    Docker Rob... Glad your pool is ok and you are in control. Its a great feeling! Enjoy the forum!
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

  18. Back To Top    #18

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    Re: How quickly can the Sun &quot;eat&quot; your Chlorine

    Quote Originally Posted by Jezza View Post
    I am running my SWG about 8 hours at 100% to keep up.
    Wow Jezza, that's pretty intense mate !

    Since getting my new test kit and starting to get my head around all this I've been able to drop my SWG run time from 8 hours a day at 80% to 4 hours a day at 60% and I reckon I can get that down even further. FC is staying constant around 7ppm, CYA is still a bit low, but I'm gradually pushing it up.

    We've got a 40 degree C (+100 degree F) day here right now and Total Fire Ban so I'm keeping a close eye on what happens to my FC loss today.

    - - - Updated - - -

    Quote Originally Posted by Jezza View Post
    I am running my SWG about 8 hours at 100% to keep up.
    Wow Jezza, that's pretty intense mate !

    Since getting my new test kit and starting to get my head around all this I've been able to drop my SWG run time from 8 hours a day at 80% to 4 hours a day at 60% and I reckon I can get that down even further. FC is staying constant around 7ppm, CYA is still a bit low, but I'm gradually pushing it up.

    We've got a 40 degree C (+100 degree F) day here right now and Total Fire Ban so I'm keeping a close eye on what happens to my FC loss today.
    39,000 litre (10,000 US gallons) IG vinyl salt water, Waterco S600 Sand filter, Zodiac Tri Chlorinator, Hurlcon E Series 230 pump, Taylors K-2006C Test Kit

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