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Thread: How much FC is too much for a vinyl liner?

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    How much FC is too much for a vinyl liner?

    What is (if any) threshold where FC could damage your liner? I mean I see Mustard Yellow shock recommendations at like 30 or higher in some cases where CYA is slightly larger.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Patrick_B's Avatar
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    Re: How much FC is too much for a vinyl liner?

    Stay within guidelines for your Cya levels, shock or otherwise and you will be fine. Outside those parameters is dangerous for a liner pool in particular.
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    Re: How much FC is too much for a vinyl liner?

    It all depends on CYA levels. In theory you could have a high enough CYA level that 500 ppm of FC would be safe, though I'm not willing to test out that theory. On the opposite end of the spectrum a pool with a true 0 CYA level could suffer some liner damage with just 10 ppm FC.
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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    Re: How much FC is too much for a vinyl liner?

    Quote Originally Posted by Donldson View Post
    It all depends on CYA levels. In theory you could have a high enough CYA level that 500 ppm of FC would be safe, though I'm not willing to test out that theory. On the opposite end of the spectrum a pool with a true 0 CYA level could suffer some liner damage with just 10 ppm FC.
    And by damage, is that staining?
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Re: How much FC is too much for a vinyl liner?

    Quote Originally Posted by Patrick_B View Post
    Stay within guidelines for your Cya levels, shock or otherwise and you will be fine. Outside those parameters is dangerous for a liner pool in particular.
    I've been wondering about this myself....By guidance, do you mean somewhere between recommended level and SLAM level, or is there a recommended, for example, no more than 3ppm over recommended level?
    20000 gallon vinyl liner in ground pool
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    Re: How much FC is too much for a vinyl liner?

    Bleaching, liner degradation, generally bad stuff. But to have a true 0 CYA it would have to be a fresh fill that has never had any stabilizer or stabilized chlorine added. Even just the tiniest bit of CYA in the water helps to buffer the effects.

    So, out of curiosity, why do you ask?

    And 440, water is completely safe to enter anywhere between minimum and SLAM levels. Below that and it might not be sanitary, above that and the chlorine can be increasingly harsh.
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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    Re: How much FC is too much for a vinyl liner?

    Quote Originally Posted by 440dodge440 View Post
    I've been wondering about this myself....By guidance, do you mean somewhere between recommended level and SLAM level, or is there a recommended, for example, no more than 3ppm over recommended level?
    Between, or up too a given shock value based on your Cya level. Not more.
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    Re: How much FC is too much for a vinyl liner?

    Thanks...I keep mine 1-2 ppm above recommended 5ppm, so I wanted to make sure I wasn't doing any damage....
    20000 gallon vinyl liner in ground pool
    16' X 34' rectangular diving pool
    Hayward Pro Grid DE Filter
    Hayward 1 hp Super Pump
    TF-100 Test Kit Stenner 45MPHP10

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    Re: How much FC is too much for a vinyl liner?

    Quote Originally Posted by Donldson View Post
    Bleaching, liner degradation, generally bad stuff. But to have a true 0 CYA it would have to be a fresh fill that has never had any stabilizer or stabilized chlorine added. Even just the tiniest bit of CYA in the water helps to buffer the effects.

    So, out of curiosity, why do you ask?
    Because I've had it at SLAM levels (maybe a 1-2 ppm over the recommended) for a few days now. I've gone through several gallons of LC (35k pool).

    I just want to make sure I'm not hurting my liner (which is only 2 years old).

    This morning for instance I was flying blind (the night before it was 17 and I added a gallon so it was 20ppm - then I realized my CYA was 40, so technically that's 4ppm over recommended levels, I have the filter on all day today and the pool has had complete sun, so I assume it will drop each day by 1.5-2ppm (maybe more?)). Again, I just don't want to damage anything.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

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    Re: How much FC is too much for a vinyl liner?

    At 40 CYA you have a pretty good buffer. Odds are good that if you go a little over SLAM levels then you won't suffer any problems. The more you go over though, the more you chance problems. There really is no absolute limit to safe levels given all the variables involved. Any time you go above SLAM level there could be problems and the further above you go the more likely that will be. The odds of a problem by occasionally going a few ppm above in a stabilized pool are very, very small.
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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