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Thread: Newbie ??? - Pool looks great but low FC and CYA; High PH

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    Newbie ??? - Pool looks great but low FC and CYA; High PH

    I have new pool. Opened mid March this year.

    My FC readings have always been low - around .5 to 1.0. Also, my CYA is low or almost non existent. PH is usually high - around 8.2

    The water looks and feels great. I have SWG and Delta UV filter as well. I am wondering if the UV filter is doing its job - allowing me to keep the FC low.

    I have not back washed the filter yet. Pressure is near start-up pressure.

    Any advice would be appreciated.
    20,000 gallon IGP, 50 sqft, infinity edge spa - 8 jets, 3 water pots and 2 bubblers
    SWG - Pentair IC40: Delta UV Filter ES Series; Pentair Quad DE 100 Filter; 1 Pentair Intelliflow VSP VS3050; 1 Pentair Whisperflow for water pots and bubblers; Pentair EasyTouch 4 remote; Pentair Intellibrites LED (white) - 2 in pool and 1 in spa; Pentair Master Temp 400 heater; Pebblesheen Finish

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    Join Date
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    Re: Newbie ??? - Pool looks great but low FC and CYA; High P

    OK here we go!

    First, get that pH in check. That is easy.

    It's a good thing your CYA is low, because your FC is low! I'll let the SWG experts jump in, but from what I have read you'll use your cell really quickly trying to keep up your FC level without CYA. That said, is your pool shaded most the time?
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    Richard320's Avatar
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    Re: Newbie ??? - Pool looks great but low FC and CYA; High P

    Robbie is correct.

    High pH can cause all kinds of problems, and it is so easy to fix. A couple of cups of acid and it's done.

    Have you tested CC? Maybe your SWG is putting out enough, but something's munching on it?
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
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    Join Date
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    NC
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    Re: Newbie ??? - Pool looks great but low FC and CYA; High P

    Quote Originally Posted by utell
    I have new pool. Opened mid March this year.
    My FC readings have always been low - around .5 to 1.0. Also, my CYA is low or almost non existent. PH is usually high - around 8.2
    The water looks and feels great. I have SWG and Delta UV filter as well. I am wondering if the UV filter is doing its job - allowing me to keep the FC low.
    I have not back washed the filter yet. Pressure is near start-up pressure.
    First, my pressure doesn't rise that much either but that doesn't mean that i don't backwash; I just don't do it as much or for as long. Your pH needs to come down to 7.5! It'll rise back up, but a little muratic will keep it in check. SWG's have a tendency to cause pH creep anyway. Test yours weekly and keep it in the 7.5-7.8 range, never higher.
    Read Pool Schools articles on SWG's.
    http://www.troublefreepool.com/pool-...ater_generator
    To summarize:
    FC 3-5 ppm
    PH 7.5-7.8
    TA 60-80
    CH
    50-300 for vinyl
    220-320 for fiberglass
    250-350 for plaster
    CYA 70-80
    Salt 200-400 ppm ABOVE recommended optimum level
    You have got to get CYA in the water to allow the SWG to function correctly. The UV generator may be helping, but was your system designed to have the SWG and UV work together?
    Triad Region of NC
    18x37 Vinyl IG (24,000 gal.), BBB & GoldLine AquaLogic PS4 SWG, Hayward 1 HP Superpump / Hayward Sand Filter / Polaris 280 cleaner / 6 deck jets / Sheer Descent Waterfall (in coping) / Brick Red Concrete Coping / Stamped Concrete Deck
    Lots of oak trees, maple trees, *and* leaves!

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    JasonLion's Avatar
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    Re: Newbie ??? - Pool looks great but low FC and CYA; High P

    UV does very little to improve things in an outdoor residential pool. UV does save dramatic amounts of chlorine in a public pool, because the UV system can break down CC, saving the chlorine that would be required to do that. But in an outdoor residential pool there is hardly any CC to begin with, so nothing much for the UV system to do (unless you are having a pool party). UV will allow you to run at a lower FC level in a public pool, or other high bather load pool, but it does not allow lower FC levels in a residential pool.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Newbie ??? - Pool looks great but low FC and CYA; High P

    Thanks for the replies. To answer:

    Pool is shaded in the afternoon. Yes, pool was designed for both SWG and UV. I had my PB do a lot of research on it after I did. I also discussed with people that have them. All loved them. My PB actually put one in his pool that he just built for himself after learning about teh benefits of them. Some say they are overkill for a resi pool; however, my water could not be clearer.

    I did a SWG boost for 24 hours. Tested again this evening. FC is 1.0 and CC is .5. PH is 8.0

    I have been adding about a quart of acid every other day. Does not seem to bring PH down much.

    Should I backwash prior to adding CYA?

    Thanks
    20,000 gallon IGP, 50 sqft, infinity edge spa - 8 jets, 3 water pots and 2 bubblers
    SWG - Pentair IC40: Delta UV Filter ES Series; Pentair Quad DE 100 Filter; 1 Pentair Intelliflow VSP VS3050; 1 Pentair Whisperflow for water pots and bubblers; Pentair EasyTouch 4 remote; Pentair Intellibrites LED (white) - 2 in pool and 1 in spa; Pentair Master Temp 400 heater; Pebblesheen Finish

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