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Thread: High CYA levels (Chlorine Correlation)

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    High CYA levels (Chlorine Correlation)

    Hi all, I am a new pool owner. Recently, I got my chemicals checked and I noticed that my pool has 100ppm CYA. What should I do? Also, does this mean I need to keep the FC levels higher in order for the pool to be safe to swim in? Its currently around 7 ppm FC.

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    Mod Squad pooldv's Avatar
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    Re: High CYA levels (Chlorine Correlation)

    Welcome to TFP!

    Yes, it does mean that. But, where did that number come from? If it came from a pool store or a test strip then it doesn't mean a lot. If it came from a TF100 or Taylor kit then it means something. Next problem, CYA tests only go to 100, so it could be 150, 250 we even saw 1200 recently.

    What test kit are you using? Is it one of these, Pool School - Test Kits Compared

    Here is the Chlorine CYA Chart that shows the appropriate chlorine level for the CYA level.
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    Re: High CYA levels (Chlorine Correlation)

    The only test kit I own is one that only shows FC and pH. The results came from a local pool store. They are as follows:
    FAC: 0
    TAC: 0
    CH: 330
    CYA: 100
    TA: 70
    pH: 7.6
    Copper: 0
    Iron: 0

    Now from what I understand, I can take these results with a grain of salt. I will purchase a test kit as soon as I can, but I would like to use the pool over this weekend, if possible. I shocked the pool last night with about 2 pounds. The chlorine is above 5 ppm (my cheap kit only goes up to 5ppm). And the pH is normal. The pool is a bit cloudy today, but it is still blue. What's the best course of action? I want to get this pool up and running ASAP. Also, I've been using 3" Trichlor tablets for chlorine.

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    Divin Dave's Avatar
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    Re: High CYA levels (Chlorine Correlation)

    I agree with pooldv about the testing method.

    However, if your CYA is actually 100, then 7 would be lowest you would want FC.
    the recommended levels for FC are percentages of teh CYA. 7% (actually 7.5)for the low end and 11.5% for the recommended upper end range.
    Pool School - Chlorine / CYA Chart
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
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    Divin Dave's Avatar
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    Re: High CYA levels (Chlorine Correlation)

    The trichlor tabs are likely the main source of the CYA. Thats why we dont recommend them for your main source of FC.
    We recommend using either Saltwater Generator, or liquid chlorine. Neither one adds anything but chlorine to the pool.

    for every 10ppm Trichlor adds, it also adds 6 ppm of CYA. The FC burns off, the CYA does not. So, over time as the CYA climbs, it becomes somewhat impossible for those tabs to add enough FC to be effective at sanitizing the pool, and keeping algae away.

    We dont recommend swimming if you cannot see the bottom of the deep end. This for safety reasons.
    If you can see the bottom, and you want to swim, then just make sure the FC is not more than 40% of the CYA level. Its safe up till then.

    Your best course of action is to get a very reliable test kit. One of them that pooldv recommended.
    Once you get it, take a full set of test results and post them here, and we can then know what to tell you on how to proceed.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
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    Re: High CYA levels (Chlorine Correlation)

    If the CYA actually turns out to be 100ish, will I need to drain and refill the pool? And how does one actually go about doing that?

    - - - Updated - - -

    Also, the pool guy insisted that I add 10 pounds of alkalinity plus to raise my TA by 10ppm. I'm starting to get very wary of these pool guys. They try to sell some chemicals every time I go there. Should I hold off on adding the "alkalinity plus"?

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    Divin Dave's Avatar
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    Re: High CYA levels (Chlorine Correlation)

    Hi TooCLool,
    if your CYA is 100 or above, the only rememdy is to drain and refill however much necessary in order to the the CYA down. Just be thankful you are not in California!!

    TA of 70 might be just fine. What TA does is buffer the pH. If pH is very unstable and you have to add muriatic acid or pH down often,, you want TA be on the low side...so 70 might be just fine. No way to know however until you can measure it often and lean what the pH is doing.

    I would recommend not to add anything until you can get a good test kit.

    And you are right. The pool stores REALLY want to sell you stuff. That is their 1st priority. Thats how they make their living. What it does to your pool is relatively inconsequential. If it messes it up, you'll just go back to buy something else. Thats what they do.

    All you will find here at TFP, is a recommendation to be able to accurately test your own water with a good test kit, and then add only what it needs. No one here wants to sell you anything.

    Once you get your kit, and you decide to maintain your pool the TFP way, you will be flat out SHOCKED *pun intended*, at how easy and inexpensive it actually is to have absolutely clear, clean and sparkly pool.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
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    Divin Dave's Avatar
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    Re: High CYA levels (Chlorine Correlation)

    Oh, about how to drain....

    The best way is to rent a submersible pump. or buy a cheap one from Harbor Freight.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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    Re: High CYA levels (Chlorine Correlation)

    There is this faucet type thing where the pool motor is. Can I hookup a hose to that and just run the motor to drain? I don't want to risk anything by draining large amounts of the water with a sub pump. Also, could it be possible that the pool CYA level is actually much lower than what the pool guy stated? I didn't realize that there was a connection between CYA levels and chlorine, so I was keeping the chlorine levels at about 3-4 ppm. The pool hasn't turned green on me yet. Also, what is the best cheap test kit that will tell me everything I would need to know? And would it be safe to swim in a pool with chlorine levels below the minimum if it's not green?

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    Re: High CYA levels (Chlorine Correlation)

    I can help you with a couple answers:
    - Could the CYA be lower than first thought? Possibly, but no one knows. That's why the test kit mentioned in the posts above are so important.
    - Now you understand the connection between Chlorine and CYA (chart link below) - that's very good! It's critical.
    - Don't look for the cheapest kit - we've all done that. For just a few dollars more than what the pool store tries to sell you, you can have the TF-100 (link below) and it will tell you ALL you need to know. As others have already stated - order the test kit right away to get accurate numbers.
    - As for a drain on your pump (?) not sure about that one. I've seen drains fittings on filters, but ..... However we don't see your pool info, so if you can specific your pool equipment it may help. Try to get us more info on that one or post a pic and it should help.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    Re: High CYA levels (Chlorine Correlation)

    Quote Originally Posted by TooCoolForPools View Post
    There is this faucet type thing where the pool motor is. Can I hookup a hose to that and just run the motor to drain? I don't want to risk anything by draining large amounts of the water with a sub pump. Also, could it be possible that the pool CYA level is actually much lower than what the pool guy stated? I didn't realize that there was a connection between CYA levels and chlorine, so I was keeping the chlorine levels at about 3-4 ppm. The pool hasn't turned green on me yet. Also, what is the best cheap test kit that will tell me everything I would need to know? And would it be safe to swim in a pool with chlorine levels below the minimum if it's not green?
    It's possible it could be lower, but if you've been using trichlor, it's probably high anyway. You can use the hose bib on your pump, but it will be slow, and you'll be running your pump continuously, which costs more in electricity where a submersible might do it cheaper/quicker. If water table is a potential issue, you can fill while you drain, but it takes MUCH longer that way (I had over 200 CYA, and after pumping the entire capacity of the pool, I had only lowered the cya to 80, so it's not very efficient either).
    17.4k gallon IG pool with attached spa (spa itself is 730gal), Super Blue Diamondbrite plaster, Circupool SI-45+ SWG, BH/Hayward Cartridge Filter, 2hp 2speed Hayward Super II pump, , Jandy Valves, Waterway Skimmers, Rheem 400k Heater, Polaris 360 cleaner, built 2000+-, replastered June 2015, TF-100 kit---Here's my pool test reading history

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