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Thread: Can't keep chlorine in pool

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    Can't keep chlorine in pool

    Hey guys I have to admit, I just stink at this. I have tried to shock my pool several times now using your method and I just can't do it. I either battle it for weeks and have to go out of town or just whatever. In my previous attempts, it would take me a couple days to get to shock level and then I'd have to go to work and during work it would drop like 8 points and I was constantly behind the 8 ball trying to catch up with the numbers and trying to buy all the cheap bleach I could. This time I bought 20 gallons of bleach and decided I was going to do it right over the weekend. FC was at 0 so I added 10 gallons right off the top. Well, I went to test and I ran out of the re-agent. The pool store was closed and closed the next day. (My continuous dilemma) I then added 3 gals every few hours so I could buy the stuff I needed. Now I'm sitting at
    Cya 45
    FC. 16

    Should I raise the CYA?
    Can I just raise the chlorine level to like 35 so that I'm not constantly playing catch up? Between running out of testing supplies, bleach and having to work I just feel like I can't ever get out in front. I have also spent hundreds of dollars on bleach and testing supplies not to mention the pool store took me for hundreds earlier this spring. I've easily spent over 1000 dollars this season and still have a pool that will not hold chlorine.


    It looks great btw
    30,000
    IG (in ground)
    vinyl
    sand filter
    SWG

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    Re: Can't keep chlorine in pool

    How much sun does it get? Recommend CYA level for a SWG is 60 to 80. Having the lower CYA will help with the shock process so leave it there or bump up to 50 if you get tons of sun. It shouldn't take you a few days to get to shock level, the single dose of bleach should do it and show up in tests 30 minutes later.

    You could raise FC to 18-20 and then hit again when it drops below shock level and keep on it. Test in the morning before work and add bleach to get back up.

    Are you following the shock process to a tee including lowering pH? What test kit? (tftestkits.net sells big bottles of the FC reagent you need) If the water looks good then shocking shouldn't take but a few days. There's something growing in your water if you're losing that much FC, it may be hidden somewhere like in ladders or behind lights so get in every cranny you can and brush. Also possible the SWG cell is not producing enough FC or worn out.
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

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    harleysilo's Avatar
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    Re: Can't keep chlorine in pool

    If it looks great, why do you need to shock?
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    Re: Can't keep chlorine in pool

    Can you tell us how many days a week you are caring for the pool? Are you skipping any days due to your work schedule? Have you been running the shock process consistantly since starting? Does your SWG work? If so, you can bump the CYA after shocking is completed and your pass the OCLT. Are you losing chlorine at night? If so how much and like spidey asked, what test kit are you using? Have you had the pool tested for ammonia?

    A full set of test results will get you further in the game if you would please post them. We need them. Thanks...
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    Re: Can't keep chlorine in pool

    Quote Originally Posted by harleysilo
    If it looks great, why do you need to shock?
    He's got FC of 0 or let it get there and the pool loses 8 ppm FC in a day. Something is consuming chlorine way too rapidly.

    If OP wants to confirm, perform an OCLT. Raise it to shock level when the sun goes off the pool, test in the morning before sun hits it. If FC loss is greater than 1 ppm something is growing in the pool consuming chlorine.

    Letting FC drop below MIN let alone zero it's a good idea to shock to get ahead of what already started.
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

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    harleysilo's Avatar
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    Re: Can't keep chlorine in pool

    I'm not sure what 3 gallons every few hours would do, but it sounds like he shocked all weekend and ended up at target shock level for a non SWG pool. Seems like the 8 chlorine loss was prior to all that blind addition of chlorine. I don't know, how long do you have to have no chlorine for algae to grow? Maybe that depends on phosphate levels and borate levels.

    If SWG is running should be no reason to get to zero....but they can be a bear to dial in.

    Spidey is right, only way to know for sure is the OCLT.
    18'x43' Sport Pool
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    Re: Can't keep chlorine in pool

    Ok I'm not sure i can answer all these questions. I live in s Louisiana so it's very hot and there is a ton of sun. Did I read right that one gallon of bleach should have a big effect in a 30,000 gallon pool? I am shocking simply bc the chlorine level falls all the way to zero. I'm scared that the swg is broken
    30,000
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    vinyl
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    SWG

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    Re: Can't keep chlorine in pool

    You're going to need a test kit that we recommend. That kit will pay for itself within a single season.

    If can say what testing you're doing maybe a FAS-DPD test is all you need.

    So please more info on how you are testing and test results.

    Your trouble sounds small. But you must get a good test kit and provide results.

    If your swg cEll isn't working we can address that. But you must have accurate test results.
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

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    Re: Can't keep chlorine in pool

    I have the recommended Taylor K-2006
    So FC dropped 3 over night which seems better than it has been.
    This morning
    FC 13
    CC .5
    PH 7.6
    30,000
    IG (in ground)
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    SWG

  10. Back To Top    #10

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    Re: Can't keep chlorine in pool

    Oh I don't know what OCLT is
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    Richard320's Avatar
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    Re: Can't keep chlorine in pool

    Quote Originally Posted by whodat?
    Oh I don't know what OCLT is
    Sounds like you just did it!

    pool-school/overnight_fc_test
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    Re: Can't keep chlorine in pool

    Quote Originally Posted by whodat?
    I have the recommended Taylor K-2006
    So FC dropped 3 over night which seems better than it has been.
    This morning
    FC 13
    CC .5
    PH 7.6
    You're getting closer, keep following the shock process.

    Previously you stated you had a CYA level of 45, so according to the Chlorine/CYA chart shock level is ~18.
    If you dropped 3 overnight (with no sun) then something is still consuming your chlorine. Bring it up to 18 (You only had it at 16 before it consumed 3 overnight), keep it at 18 until you pass the OCLT. You didn't pass last night.

    Keep following the shock process. You need ~2.5 gallons of 6% bleach to get it up from 13 to 18.
    Rick
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    Re: Can't keep chlorine in pool

    It's tough to do the Shock Process when you have to work, but it can still be done just fine. Because you cannot babysit the pool, it will take a little longer to complete the process. Lots of folks have to do it this way.

    Test and raise to shock level each morning and each evening. If you can get in 2 or 3 tests/raises in the evening, that is even better. In fact, the more you can do when the sun is off the pool, the better. No sunlight burning any chlorine and all chlorine is being used fighting the organics in the pool.
    Did I read right that one gallon of bleach should have a big effect in a 30,000 gallon pool?
    No, one gallon will not have a big effect, in fact 1 gal 6% will add about 2ppm and 1 gal of 8.25% will add about 3ppm.

    I am shocking simply bc the chlorine level falls all the way to zero. I'm scared that the swg is broken
    Collect a sample right at the return and test it for chlorine. That should tell you whether or not the cell is producing anything.
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  14. Back To Top    #14

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    Re: Can't keep chlorine in pool

    Ah ok. Well I added 3 gals of 8% . So I should be well in range
    30,000
    IG (in ground)
    vinyl
    sand filter
    SWG

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    Re: Can't keep chlorine in pool

    Test FC/CC 30-60 minutes after you add the bleach to make sure you're maintaining shock levels for your CYA. Test and add bleach again before bed if you need to get the level up. The key to shocking is maintaining that consistent level to outpace any algae reproduction.

    That you lost 3 ppm overnight and have .5 CC something is growing in your pool which is why your SWG couldn't keep up. You can be sure it's not faulty yet , but with the shock process you will kill everything growing. Don't forget to brush and the other parts of shocking including monitoring pressure.

    How's the water look? Don't neglect the nooks and crannies where algae could be growing.
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

  16. Back To Top    #16

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    Re: Can't keep chlorine in pool

    It's possible your SWG is broken or that you have significant scaling in the cell -- either calcium carbonate scaling if your CH and TA are high or calcium phosphate scaling if your CH and phosphate levels are very high. I'd check your cell and clean it with acid per directions. You can also check to see if a chlorine sample taken from the return flow water is at a higher FC than the rest of the water though the difference won't be that large -- roughly 2 to 4 ppm FC difference, depending on your turnover rate and SWG on-time percentage (set that to 100% before doing the test).
    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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  17. Back To Top    #17

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    Re: Can't keep chlorine in pool

    Well I didn't lose any FC last night and no CC. The pool has looked great all along. I'm not exaggerating there, there are no signs of algae to the eye. So I think I'm done right? If it falls to zero again then it's a problem with the SWG? I guess I need to check the cell but I have never done that before so I'm nervous
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    Re: Can't keep chlorine in pool

    Or you could simply "maintain" your pool with about 2-3 ppm clorox each day. If your FC begins to rise, you can assume the SWG is operating and start cutting back on the Clorox. That way, you don't have to touch the SWG to see if it's functioning.
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