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Thread: Does CYA levels change by tempurature?

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    iggy's Avatar
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    Does CYA levels change by tempurature?

    I test my pool weekly at a number of Leslie Pool stores.
    The CYA levels change from 80 to 100.
    I think it must be the person doing the test is getting a close guess.

    What is your opinion?


    Iggy
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    Yep I would say you are getting a guesstiment, and not actual results.
    Why do you take it to the store to test? Why not get your own test kit?
    27' Round AG, 17,200 gallons, sand filter

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    frustratedpoolmom's Avatar
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    I can tell you firsthand, no, it's a testing error.

    My CYA tests (performed with my kit) do not change, prior to heater being turned on the water was 76. Heater on, water 86. CYA tested the same.

    It's the pool stores, their testing machines are off or something.

    FYI, that's a little high for CYA...JMHO
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    iggy's Avatar
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    Re: Does CYA levels change by tempurature?

    I do my CYA test a few times a year myself and I get 100.
    My pool is new and the builder added 8 lbs of CYA in the pool before I can say a word and it has been high ever since.
    I suspect after a few time I lower after rains it will go down. Here in Arizona high CYA is needed to help the chlorine sustain in the pool after long sunny hot days. Anyway that is what I've been told.

    Now I have to figure out a way to keep the rattle snakes out of the pool.

    So thank you for the information. Have a great summer.
    Iggy in the cool part of Arizona 8)
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    Rattle snakes......Kind of makes your CYA a none issue.
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    iggy's Avatar
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    Quote Originally Posted by Countrygirl
    Rattle snakes......Kind of makes your CYA a none issue.
    Rattlesnakes are cool.
    The good part is that I no longer have any frogs in the pool. LOL
    Anyway we do have plans for a rattlesnake bbq in a few weeks.....

    Iggy
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    Does CYA testing result change with the pump running versus testing after pump has been off for say 8 hours?
    9x18 x 52" AG intex ultra. 1hp Waterco pump. 75sqft Waterco Cart. 4600 gal. 12 mil solar cover. I love BBB

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    Mod Squad JohnT's Avatar
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    Quote Originally Posted by fishandfly
    Does CYA testing result change with the pump running versus testing after pump has been off for say 8 hours?
    No.
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    Kind of makes your CYA a none issue. Thanks Countrygirl now I have to clean the coffee off my computer.
    Ric W
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    iggy's Avatar
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    Does this sound right?

    So what I have learned is that CYA stays in the water and does not change ppm unless you remove water.
    Temperature nor any other factor changes CYA in the pool.
    As much as I know it is imperative to have 50 to 80 ppm in sunny areas and high pool usage to help maintaining the good Chlorine.
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    One season, I had my pool at 30 CYA and I'm in sunny Houston, Tx. so you don't have to have higher CYA levels but you must maintain sufficient FC. It all depends on what your trying to do. Lower CYA means a faster FC burn off from the sun but Higher CYA means higher FC levels necessary for sanitation. So lower CYA also means lower FC levels necessary. So its a see-saw and the only real equation on what level CYA is best is what burnoff of FC and that can be hard to figure out.

    Either way ChemGeeks chart is indispensable. This tells you how much FC you need for CYA levels. Keep your pool within these limits and it will save you. http://www.troublefreepool.com/viewtopic.php?t=2346
    36,000 gallon IG Gunite (40 x 20), 1.5 HP Hayward pump, Pentair Nautilus NS-48 DE filter, 2 skimmers, 12 - (2 x 20) Fafco Solar Panels (Goldline controller not hooked up yet), Hayward Swimpure Plus SWG, Blue Pearl Robot cleaner. New Dr. Wellness X-12 standalone Lifestyle Spa.

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    Quote Originally Posted by mac4lyfe
    One season, I had my pool at 30 CYA and I'm in sunny Houston, Tx. so you don't have to have higher CYA levels but you must maintain sufficient FC. It all depends on what your trying to do. Lower CYA means a faster FC burn off from the sun but Higher CYA means higher FC levels necessary for sanitation. So lower CYA also means lower FC levels necessary. So its a see-saw and the only real equation on what level CYA is best is what burnoff of FC and that can be hard to figure out.
    Either way ChemGeeks chart is indispensable. This tells you how much FC you need for CYA levels. Keep your pool within these limits and it will save you. http://www.troublefreepool.com/viewtopic.php?t=2346
    I have a Goldline/Hayward SWG and they want the level between 60-80.
    Also they say this:
    Stabilizer is also known at cyanuric acid or isocyanuric acid. Refer to local codes regarding its' use. Stabilizer helps maintain the chlorine residual in the pool by protecting it from the UV rays from the sun. Without stabilizer, the chlorinator would have to produce much more chlorine in order to keep the desired residual level in the pool. Add enough stabilizer to be near the top end of the range at the same time you add salt.

    I will wait until fall to lower water level and reduce my CYA to 80 ppm.
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    Quote Originally Posted by iggy

    I have a Goldline/Hayward SWG and they want the level between 60-80.
    Also they say this:
    Without stabilizer, the chlorinator would have to produce much more chlorine in order to keep the desired residual level in the pool. Add enough stabilizer to be near the top end of the range at the same time you add salt.

    I will wait until fall to lower water level and reduce my CYA to 80 ppm.
    Most SWG manufacturers say to have a higher CYA level. That makes sense so that the cell doesn't have to work as hard (which means you would have to replace more often)

    I don't know if I totally agree with the statement in bold though. What do you consider much more chlorine? The target level of FC is lower when your CYA is lower and its a near linear equation.

    CYA ........... Min FC3 ..... Target FC ...... Yel/Mstrd Min ...... Shock FC ..... Yel/MstrdShock
    10 ............... 0.81 ............. 1.21 .................. 1.61 .................... 4.5 .................. 7.1
    40 ............... 2.9 ............... 4.6 .................... 6.1 ................... 16.0 ................ 23.8
    80 ............... 5.8 ............... 9.1 .................. 12.0 ................... 31.42 ............... 46.12
    120 ............. 8.7 ............. 13.6 .................. 17.9 ................... 46.72 ............... 68.42

    Let's look at a few levels for comparison. At 80ppm CYA the target FC level is 9.1ppm which is half of the 40ppm CYA level of 4.6ppm. So realize that at the higher CYA level you need twice as much FC. So the key factor is what is your FC burn rate? if your FC level stays fairly constant than you may not need the extra CYA. On the other hand if your FC is being rapidly depleted (based on many factors) than the extra CYA may be beneficial. My burn rate may be totally different than your burn rate and the only way to know is by constant testing/data. Maybe your not doing alot of swimming. That would reduce your burn rate. So far this year, I'm burning alot more FC than at the end of last year (even at a higher CYA). I think its because we've just reopened the pool recently and we've done alot more swimming earlier and there's probably residual organics.

    It really depends on what level you can maintain. It may be easier to maintain 4.6 ppm FC even though it's being depleted faster than 9.1 ppm FC. If it wasn't then why not raise your cya to as high as possible? Because you then have to maintain a much higher FC level which for BBB means much more bleach. What's easier, a small bottle of bleach several times or many gallon jugs a few times? You have to strike a balance and everyones situation will be a little different.
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    JasonLion's Avatar
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    mac4lyfe, the total amount of chlorine lost to sunlight goes down as the CYA level goes up, even after adjusting the FC up as suggested by the chart you quoted.

    Most SWGs suggest a CYA level of 60 to 80 because lower CYA levels consume more chlorine, which requires a larger cell, which costs more, and they want to keep prices down. CYA levels above 80 start to get problematic for a variety of reasons, otherwise they would probably recommend even higher levels.
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    Oh, I'm not disagreeing with you but my point is "what's considered much much more?" That's fairly subjective and just by doubling the CYA level does not equate to halfing the burn rate. I said above that manufactures want the SWG to run as little as necessary which makes sense but for someone using the BBB method it may not ring true to keep their CYA at a higher (lets say 80ppm) level. Even though the burn rate is lower, the amount of FC necessary is higher which means larger doses of bleach albeit less often. Higher CYA levels I think lends itself to greater algae growth because people take the pool stores advice to keep 2 ppm FC which isn't even close to the target.
    36,000 gallon IG Gunite (40 x 20), 1.5 HP Hayward pump, Pentair Nautilus NS-48 DE filter, 2 skimmers, 12 - (2 x 20) Fafco Solar Panels (Goldline controller not hooked up yet), Hayward Swimpure Plus SWG, Blue Pearl Robot cleaner. New Dr. Wellness X-12 standalone Lifestyle Spa.

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    Quote Originally Posted by mac4lyfe
    Oh, I'm not disagreeing with you but my point is "what's considered much much more?" That's fairly subjective and just by doubling the CYA level does not equate to halfing the burn rate. I said above that manufactures want the SWG to run as little as necessary which makes sense but for someone using the BBB method it may not ring true to keep their CYA at a higher (lets say 80ppm) level.
    Absolutely. I recommend CYA at 30 to 50 for a typical BBB pool. Chlorine usage is higher, but not by all that much compared to CYA at 60 to 80. Shocking is much simpler at the lower CYA level and the standard FC level is low enough that the standard OTO test can be used for day to day testing. If you have a SWG the odds of needing to shock are lower and testing isn't as frequent so the higher CYA level makes more sense.
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    I didn't even think about FC testing and being easier (less $$) at lower levels as well. Great points...
    36,000 gallon IG Gunite (40 x 20), 1.5 HP Hayward pump, Pentair Nautilus NS-48 DE filter, 2 skimmers, 12 - (2 x 20) Fafco Solar Panels (Goldline controller not hooked up yet), Hayward Swimpure Plus SWG, Blue Pearl Robot cleaner. New Dr. Wellness X-12 standalone Lifestyle Spa.

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