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Thread: CYA loss around 10ppm per month

  1. Back To Top    #1

    Join Date
    Jun 2011
    Location
    Coastal, NJ
    Posts
    15

    CYA loss around 10ppm per month

    I also see a higher than average CYA loss, around 10ppm per month. Pretty sure it's not due to splash out or water replacement, as my CH remains constant. We do keep the pool on the warm side, around 90, so maybe that's the culprit. Really not a problem, I throw a few tabs in the feeder about once a month and use the extra time to have another drink.
    19,000 gallon outdoor in-ground 16x32' vinyl, Hayward Tristar 3/4 HP pump, Hayward 4820 DE filter, 9 Aquatherm solar panels, Hayward H350FD heater, TF-100 test kit.

  2. Back To Top    #2

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: connection between air in the return and CYA consumption

    Yes, warmer water temperatures will accelerate the chlorine breakdown of CYA. Higher pH will also accelerate it. Is your pH on the higher side, say 7.8 instead of 7.5?
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  3. Back To Top    #3

    Join Date
    Jun 2011
    Location
    Coastal, NJ
    Posts
    15

    Re: connection between air in the return and CYA consumption

    The pH in the pool is around 7.5. Not much work to keep it there, seems that's just where it settles. I typically keep a bubble blanket on the pool, so the temp never really drops much. I would think that might help contribute to the loss since it's warm most of the time.

    Hot tub (separate) is around 7.8 (also seems to settle there). I do see a slightly higher CYA loss there, maybe just a little over 10ppm/month. That's also easy to manage. I just add 2-3 tsps dichlor every week, and that helps keeps the pH in check.

    Many thanks to all the experts here. This is a great site and has really helped me out!
    19,000 gallon outdoor in-ground 16x32' vinyl, Hayward Tristar 3/4 HP pump, Hayward 4820 DE filter, 9 Aquatherm solar panels, Hayward H350FD heater, TF-100 test kit.

  4. Back To Top    #4

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: connection between air in the return and CYA consumption

    Yes, whereas a pool may lose 2-3 ppm CYA per month (some report more, but that's what it is in my pool) and hot spas typically lose 5 ppm CYA per month (you are reporting more), that is usual. And yes, just adding some Dichlor instead of bleach on occasion is an easy way to keep it in balance.

    So I'm not too surprised about the CYA loss in your hot tub, but the loss in your pool still seems higher than usual. Do you have any summer rain overflow? Perhaps a leak with autofill that you don't know about?
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  5. Back To Top    #5

    Join Date
    Jun 2011
    Location
    Coastal, NJ
    Posts
    15

    Re: connection between air in the return and CYA consumption

    No autofill but we have had a fair amount of rain this year. Although I've only had to drain about 1" out so far all summer, and add about 1" during a dry spell. Started monitoring this about 2 years ago, and compare it with the CH level, which drops slightly over time (fill water has a CH of 50), but not as much as the CYA. I used to think it was splash out. When the kids where younger they would create waves with the big tubes and send water flying out of the pool.

    I have noticed if I leave the bubble cover on during a hot sunny day, when the pump turns off, the water near the surface can get pretty warm, like 94-95. Maybe that accelerates the loss? I haven't kept records on the CH/CYA loss, but I do need to add ~10ppm CYA per month throughout the season.
    19,000 gallon outdoor in-ground 16x32' vinyl, Hayward Tristar 3/4 HP pump, Hayward 4820 DE filter, 9 Aquatherm solar panels, Hayward H350FD heater, TF-100 test kit.

  6. Back To Top    #6

    Join Date
    Jun 2014
    Location
    Tucson, AZ
    Posts
    860

    Re: connection between air in the return and CYA consumption

    You can order more Taylor reagents. The melamine solution is available in 2oz bottles which gives you plenty of tests for a whole season. I also ordered larger bottles of the chlorine reagents as I used my original 0.75oz bottles up during a SLAM.

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