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Thread: pH staying at 7,2

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    pH staying at 7,2

    I can't seem to keep my PH at 7.6; it always goes down to 7.2

    Numbers as of this evening:
    CYA: 60
    FC: 3.5 (a bit low I know, I ran out of CL and haven't had a chance to get more - it was at 7 on Saturday)
    CC: 0
    PH: 7.4 - 7.2
    TA: 80
    CH: 130

    This past weekend I raised by PH using borax to get it to 7.6 on Friday and again on Sunday (it dropped back to 7.2 on Sat). This also raised TA from 60 to 70 and on Sunday I raised TA further to 80. Today it measured 7.4 - 7.2; not quite either color just right in between.

    My wife and daughter are complaining that the pool water is stinging their eyes at 7.2. The FC was at 7 that day but that's in the range for a CYA of 60 (rec FC 5-9).

    Should I raise my TA more?
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

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    Re: pH staying at 7,2

    Yes, you can raise your TA more which will tend to make the pH rise more, but what are you adding to the pool that is lowering the pH? Are you using Trichlor pucks/tabs? Are you using Dichlor or MPS? If you are just using bleach or chlorinating liquid with The Liquidator, then I don't understand what is making your pH drop.

    Also, I doubt that the pH of 7.2 is causing stinging eyes since that's not very low. That's more likely to be caused by Combined Chlorine (CC) so you should check for that. Or if they are keeping their eyes open in the water for long periods of time then that can cause pressure which is less likely to occur in pools with higher salt levels. Nevertheless, raise the pH and see if your daughter notices any difference.
    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"

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    Re: pH staying at 7,2

    I'm only using liquid CL via the LQ and manually added as needed. So I'm equally confused why it keeps drifting down. I haven't had to fill it often since I have it covered with a solar blanket...after the recent rains we've had it hasn't gone lower than 7.2 and I've always adjusted back to 7.4 or 7.6 only to see it go down again. It's been about the last month and a half that I've been having trouble keeping it at 7.4. Maybe pollens or dust right now? The cover is kind of dirty/dusty.

    I measured the water before we went swimming and the FC was 7 and the CC was 0 - that was about 2 hours before we got in. 3 hours after we swam I retested and FC was 6 and CC was still 0 so I don't think we had any CC while we were swimming...the eyes open makes sense with my daughter - she was diving for rings (she's a fish! )

    Per the pool calc to raise my PH from 7.2 to 7.6 I should be seeing TA rise by about 8 too, but I've never seen it move that much; it started at 60 back in January and moved to 70 after several attempts at raising the PH. Last weekend I dosed it with baking soda to bump it to 80. How high would you recommend I take the TA to next? Increments of 10?

    Thanks Chem!
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

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    Re: pH staying at 7,2

    One other thing to note is that you should measure the pH at roughly the same FC level, preferably when the FC is lower (if it varies -- with the LQ it probably doesn't vary too much, but may be lowest just before the pump comes back on for the day).

    As for TA, yes I'd just go up in 10 ppm increments and wait some days and see if it makes a difference. No reason to overshoot this. I'm still puzzled, though.
    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"

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    Re: pH staying at 7,2

    You and me both. I'll try for 10 today.
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

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    frustratedpoolmom's Avatar
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    Re: pH staying at 7,2

    Keeping the solar cover on frequently will cause your ph to drop as you describe. I experience this in my pool - and its covered with the blanket when it's not used.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    dmanb2b's Avatar
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    Re: pH staying at 7,2

    Quote Originally Posted by frustratedpoolmom
    Keeping the solar cover on frequently will cause your ph to drop as you describe. I experience this in my pool - and its covered with the blanket when it's not used.
    Same here. Not sure why, but even if we are not using the pool in the middle of the day, we uncover it for at least an hour to "air out"...Likely would be fixed if I just bumped TA up a bit, but then my PH rises in the hot months when we use the pool the most
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

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    Re: pH staying at 7,2

    Interesting...
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

  9. Back To Top    #9

    Re: pH staying at 7,2

    Keeping the pool covered will reduce the outgassing of carbon dioxide, which will reduce pH rise. Uncovering the pool allows carbon dioxide to off gas, which will raise the pH. Warmer water and aeration from increase usage will also increase carbon dioxide off gassing. I'm not sure why there would be a pH drop from using a cover.

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