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Thread: PH & Salt Water Chlorine Generator

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    PH & Salt Water Chlorine Generator

    I understand that a Salt Water Chlorine Generator will naturally raise the PH of my pool. Mine goes to 8.2+ above the test parameters. I am so tired of adding more and more acid every week. Is there anything that I can do to help stabilize my PH so I am not constantly buying & adding more acid? Thanks for any help.
    Mike

    33,000 gallon IG pebble, SWG - Aqua Rite w/ Hayward T Cell 15, DE filter - Pentair FNSP 60, single speed pump, pool age 13 yr, spa, test kit TF100, Polaris 280

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    Mod Squad Jimrahbe's Avatar
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    Re: PH & Salt Water Chlorine Generator

    Mike,

    What is your TA reading? I suspect it is high and driving your PH up. I had the same problem as you and read the following link which fixed or slowed the problem. My PH will stay between 7.6 and 7.8 for several of months before I have to drive it back down. The real key is to drop it to 7.0 and keep checking it every few hours and drive it back to 7.0. Worked for me anyhow..

    http://www.troublefreepool.com/conte...tal-alkalinity

    Thanks,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Calder Spa.

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    Re: PH & Salt Water Chlorine Generator

    Quote Originally Posted by Jimrahbe View Post
    Mike,

    What is your TA reading? I suspect it is high and driving your PH up. I had the same problem as you and read the following link which fixed or slowed the problem. My PH will stay between 7.6 and 7.8 for several of months before I have to drive it back down. The real key is to drop it to 7.0 and keep checking it every few hours and drive it back to 7.0. Worked for me anyhow..

    http://www.troublefreepool.com/conte...tal-alkalinity

    Thanks,

    Jim R.
    You are correct Jim. My TA is 110
    Mike

    33,000 gallon IG pebble, SWG - Aqua Rite w/ Hayward T Cell 15, DE filter - Pentair FNSP 60, single speed pump, pool age 13 yr, spa, test kit TF100, Polaris 280

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    Re: PH & Salt Water Chlorine Generator

    Most of the pH rise in pools either using a hypochlorite source of chlorine or using a saltwater chlorine generator is from carbon dioxide outgassing because the TA is set too high or the pH too low. Try lowering the TA to 70 ppm and target 7.7 as your pH and see if things improve.
    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
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    Mod Squad YippeeSkippy's Avatar
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    Re: PH & Salt Water Chlorine Generator

    My SWG does not seem to raise my pH, thankfully.

    I wondered if you might have some water feature that may be contributing to your pH rise because of the aeration it produces as the water falls? This could be one explanation for your rising pH, along with a too high TA.
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
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    Re: PH & Salt Water Chlorine Generator

    I'll give my experience after three years just as a data point - nothing more.

    We have a SWCG
    Our TA settles at 40-50 (with no intentional adjustment)
    I target pH at 7.2 letting it rise to 7.8/8.0.
    Then I add MA and repeat - all summer.
    No issue for me, simple process. About a gallon a week. Stand upwind and pour carefully - no concerns.

    I'd prefer my pH rise would stop at some level. I'd let it rise just to see if it does, but the problem is my CH gets high by the end of summer (500+) [I close my pool in the winter and drain down some then and a few times during the winter - then the rain refills in spring with CH free water thus lowering my CH to start the year] and if my pH gets much/any over 8, my water will get cloudy from the CH precipitating. At least that's what I think is happening. So I add MA and have a TFP.

    I chalk up the above being due to my pool's personality. Each pool has one. The basic equations are the same for all but the individual factors present affect things one way or the other.
    18'x38' Rectangle (3'-8 1/2' deep w/ diving board) - 27K gal. w/ gray plaster
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    Re: PH & Salt Water Chlorine Generator

    So if the TA settles to some amount where acid addition isn't lowering it, then that means that either the amount of TA being added from evaporation and refill is matching that lowered from the acid addition or that the pH rise is not from carbon dioxide outgassing (or a combination of these two effects). Another source of pH rise in SWCG pools is from undissolved chlorine gas outgassing and when acid is added to compensate for that there is no net change in TA.

    Rather than have a large pH range, if you use 50 ppm Borates then the pH won't rise as quickly. You may still use about the same amount of acid over time, but could add it less frequently.
    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 & Salt Water Chlorine Generator

    Quote Originally Posted by chem geek View Post
    So if the TA settles to some amount where acid addition isn't lowering it, then that means that either the amount of TA being added from evaporation and refill is matching that lowered from the acid addition or that the pH rise is not from carbon dioxide outgassing (or a combination of these two effects). Another source of pH rise in SWCG pools is from undissolved chlorine gas outgassing and when acid is added to compensate for that there is no net change in TA.

    Rather than have a large pH range, if you use 50 ppm Borates then the pH won't rise as quickly. You may still use about the same amount of acid over time, but could add it less frequently.
    Hopefully this isn't viewed as a hijack...should be my last comment...but it's exactly pertinent to the OP's question.

    In my second year, I did add borates to roughly 50 ppm and worked the additions that way. Adding more less frequently, so the same amount over time. However, since I have to drain maybe 20% at closing each year, then multiple additional drainings during the winter to keep the water level down, when spring comes, my borates are were way low. Which then needed to be purchased and replenished. I decided not to incur that extra expense annually since the MA change to less frequent additions of larger amounts wasn't saving me anything to offset it. It was just a convenience factor. And since my pool is so sparkly anyway, the bonus sparkles from borates weren't a draw. I didn't really notice them anyway.

    So, I'm probably doing the best I can in my case. Again, sorry if I took over too long.
    18'x38' Rectangle (3'-8 1/2' deep w/ diving board) - 27K gal. w/ gray plaster
    Hayward equipment (cartridge filter, 2-speed pump, SWCG, automation) View Our Build
    Coverstar automatic pool cover | StoneMakers concrete retaining wall and decking
    Spring 2013 Build | Dolphin Active 20 robot cleaner | Support TFP!

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