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Thread: PH is constantly in Pool and Spa

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    PH is constantly in Pool and Spa

    Hello,

    I've been following the forums here for a bit now and been doing alot of research and it's been super helpful. So first off thank you to everyone.
    So Ive been using the BBB method to take care of my pool and have had no serious issues this far but I do have a few questions that everyone can hopefully help me with.

    Using Taylor 2006:
    FC: 4ppm (usually keep around 5-6)
    CC: 0
    PH 7.8
    TA: 90
    CH: 140
    CYA: 90 (I realize this is high and working on draining and refill 50% soon)

    My question is in regards to PH. It seems that i'm constantly adding Muriatic acid (31%) every other night to lower PH to 7.4 Range but I can never seem to get it there. I use Pool Calculator and follow it closely. What am I doing wrong here? Do I need to lower TA even more to get PH in check? I do have an aerator but never really use it. Thanks in advance for input.

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    Re: PH is constantly in Pool and Spa

    In regards to pool specs:

    8200 gallon in ground pebletec pool
    Pent-air VS pump w vacuum
    Currently using BBB method and using Taylor 2006 Test kit


    Spa - 290 Gallon Hot Spring Bolt with ozonator

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    Re: PH is constantly in Pool and Spa

    Can you please add your signature and provide us with more detail. What type of pool and when was it built? What type of aeration devices do you have as well (if any)? Also, when are you adding the bleach and when are you testing? It could be that your pool wants to stay at the 7.8 range (some pools react funny).

    It took my TA to drop to around 70 before my PH finally stabilized at the 7.5 range. It was creeping up from 7.5 to 7.8 every 4 days. Went from TA of 130 to 90 and still had rising PH (not as fast). Not until 70-80 did the pools PH stabilize. Please advise!
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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    Re: PH is constantly in Pool and Spa

    I just put info in signature, sorry about that. I also posted it here on thread. I usually add bleach at end of day around 7pm. The pool was completed around end of July this year so its still pretty new. As far as aerator, it's just a simple nozzle that sprays water on to the pool. I usually test in the afternoon, add chems at night and test the following day.

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    Mod Squad pooldv's Avatar
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    Re: PH is constantly in Pool and Spa

    Welcome to TFP!

    I tried to click the show sig box and it doesn't look like you a have a sig set up. Don't forget to save it when you're finished. More here on what to put in your sig and how to do it, Pool School - Read This BEFORE You Post

    Things that cause pH to rise
    Aeration, waterfalls, bubblers, etc
    TA above 60
    Saltwater chlorine generators

    Here is how to lower your TA, Pool School - Lower Total Alkalinity


    For your hot tub I would do this, it has a good section on controlling pH rise.
    How do I use Chlorine in my Spa (or pool)?
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    kellyfair's Avatar
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    Re: PH is constantly in Pool and Spa

    I don't know anything about IG pools, but from what I've read around here, it is pretty common for new plaster to cause ph to rise. Not sure how long that phase lasts.
    Kelly, Tampa FL
    15' by 4' Intex above ground metal frame, about 5300 gallons
    Intex 120V Krystal Clear Sand Filter Pump & Saltwater System CG-28679 with E.C.O.
    TF100 Kit and Speedstir
    Intex Auto Cleaner - works great!

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    JoyfulNoise's Avatar
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    Re: PH is constantly in Pool and Spa

    Why are you targeting a pH of 7.4? Your pH will rise to a level determined by your total alkalinity, rate of outgassing of dissolved CO2 and temperature. A pH of 7.4 may not be possible for your pool. Any pH between 7.2 and 7.8 is perfectly fine to swim in and, typically speaking, the lower the pH the faster it will rise.

    Try lowering your TA to 80ppm or less and then target a pH range of 7.6 to 7.8. Add acid only when your pH is above 7.8 and don't go lower than 7.6. Then see how your acid demand is.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Mod Squad Jimrahbe's Avatar
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    Re: PH is constantly in Pool and Spa

    Sergio,

    It is pretty common for pH to increase over time, especially in new pools. It is also common for it to jump right back to where it was if all you do is add Muriatic Acid and do nothing else.

    Using pool math, what you need to do is add enough MA to reduce the pH to 7.0. Then take a reading of the TA value and record it. Turn on whatever aeration you have (the more the better). In three or four hours measure pH and TA again. When the pH raises to 7.3/7.4, add MA again to drive it back to 7.0. You need to keep doing this, over and over, until your TA reads between 50 and 60. Then leave the aeration on until the PH comes up to 7.4/7.5.

    You need to set aside a day or two to do this, you can't just do it once a day, as that will just not work.

    This may or my not cause your pH to stabilize, but if nothing else, it should mean that your time between adding MA doses, should be greatly increased.

    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 is constantly in Pool and Spa

    Quote Originally Posted by Sergio001R View Post
    In regards to pool specs: 8200 gallon in ground pebletec pool Spa - 290 Gallon Hot Spring Bolt with ozonator
    Sergio:

    You have a concrete/plaster pool. Your PH will increase for quite a while until the plaster cures and then your PH should stabilize. It is the nature of the beast. If you have the Spa off and TA at a low point, you will still have increasing PH, which will require almost daily additions of MA. Thanks!
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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    Re: PH is constantly in Pool and Spa

    I had the same issue. lowered TA to 50 and it fixed the problem. Not sure who came up with 80-120 guidelines posted everywhere
    Inground 28000 gal Concrete, Hayward Progrid DE filter 6020, US motors 1.5hp pump (3450rpm) , Polaris 360
    600 gal hot tub, Spa Vita, Nature2+MPS

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    Re: PH is constantly in Pool and Spa

    I've had this issue ever since I moved into a house with a pool 5 years ago. The plaster was redone a couple years before we moved in, which we hoped was causing the issue, but now that it's been at least 6 or 7 years since the re-plaster job, I think it's safe to say that we're well beyond the point that this should still be an issue. After some years of posting, researching and trying various suggestions, I finally just gave up. I have no water features, and I've tried everything suggested here, including lowering TA all the way down to 50, but nothing has stopped -- or even noticeably slowed down -- the pH rise. I've also had local pool professionals take a look at my situation, but they seem to know far less than the people on this forum.

    For a while I theorized that perhaps my cleaner setup was resulting in very low pressure on the suction side of the pump, causing cavitation and resulting in excessive aeration which, in turn, might cause pH rise. I later replaced my cleaner line with a much larger diameter pipe, however, reducing the negative pressure a bit on the suction side of the pump and reducing cavitation, but my pH rise was not effected.

    On many occasions I've considered adding borates to slow the rise down, and may still do so someday, but given that this doesn't actually reduce the amount of acid needed, I just never pulled the trigger on it. According to the information I've read, adding borates slows the pH rise, but it also requires equivalently more acid to raise the pH by the same amount. My pool seems to be relatively stable other than this, so I decided not to mess with it by adding other chemicals.

    In the end I just came to the conclusion that my regimen requires me to add two liquid chemicals instead of one. Over time, and after a lot of trial and error, I settled in on a range of Cl and pH that would allow me to add the two chemicals at the same time (i.e. one after the other) about twice a week during the summer, and maintain CSI balance according to the pool calculator. When I need to add chlorine, I simply need to add acid as well. The numbers and ranges shift during the winter when the water temp drops, which effects the CSI balance, but with far fewer chlorine additions needed, it's not all that big of a deal to add Cl and acid on different days if needed.

    I'm still endlessly frustrated to hear about other people not having to deal with this (it's just not fair!), or to read about such simple solutions solving the issue for others when these methods seem to have zero effect for me. I'm also still really curious why my direct neighbor does not have any such issue with his pool (I did some measurements over a number of days between their chemical additions and their pH did not budge.) In the end, however, I had to try to come to terms with the fact that there are unknown factors involved, and that some pools, for whatever reason, are just going to have this issue. I can definitely find other people complaining about this, so even though the people with this issue are in the minority, they're not alone.

    In my case, my best guess at this point is that perhaps there is something about my plaster that's causing this -- some specific issue with the composition -- that will hopefully be resolved when it's eventually time to redo the plaster once again. I'm still years away from that, however, so I just live with the idea that some pools have this issue.

    Given that my pool chemistry is fairly trouble free other than this issue, I think that things could be a lot worse. The need to add acid as well as chlorine all the time is annoying, but relatively speaking it's not "that" big of a deal.

    Please let us know if you ever find a solution -- I'm always eager to hear what other people do to combat this.

    Thanks,

    Larry
    Los Angeles, CA -- 22K gallon in-ground plaster pool with spa, built around 1980, replastered around 2009-2010.
    Pentair Intelliflo VS (variable speed) pump and Quad 100 DE filter. Older "MiniMax" gas heater. Pentair Rebel cleaner.
    NO SWG - Liquid Cl only. Taylor K-2006 test kit.

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    Re: PH is constantly in Pool and Spa

    Larry:

    A solar cover (not that you need on in CA) should keep your PH from rising (but then again in your pool you never know). I had rising PH issues at 120-140 TA and now at 80, the PH stabilized (without cover). Now, the PH drops and stays low so every few days I have to let the pool breath to increase the PH. Does your pool get a lot of use (splashing around)? How about the spa (does it spill over)? Do you have any type of rotating heads that break the water surface (like I do)?

    Also, when are you testing your PH (after chlorine additions). I always test when the Liquid CL that I had has burned completely off and prior to adding any more. When I test PH after additions, especially within one hour, my PH reads very high. Just some thought!
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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