Become a TFP Supporter Pool Math Forum Rules Pool School
Page 1 of 2 12 LastLast
Results 1 to 20 of 24

Thread: why does ph go back up?

  1. Back To Top    #1

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    why does ph go back up?

    last night i had

    ta 270
    fc 1.2
    ph 8.7
    cya 10

    i poured in 2 liters of acid

    at 9am ph was 8.2
    at noon 8.5
    and at 8pm 8.7

    why is this happening?

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    Please put your pool and equipment details in your signature .. I can not remember you setup.

    pH goes up due to high TA and aeration (water features, spa, SWG, etc).
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  3. Back To Top    #3

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    i have a 15000 gallon pool which is 56000 liters
    sand filter.. 17000liter per hour pump.. all my gear is made in spain..
    i have two skimmers and a main drain..6 returns on the bottom

    no water effects or anything hooked up yet..

  4. Back To Top    #4
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    So the pH rise is likely due to your high TA. Follow the Lowering Total Alkalinity article in Pool School.

    However, you should only start doing that when all other parameters are in range and your pool is clear (I can not remember the goings on in your other threads ... another reason to keep them together).

    Your CYA seems too low (not sure how you measured below 20ppm) and your FC is certainly too low. What does your water look like?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  5. Back To Top    #5

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    the water is sparkling clear
    i lowered ph then shocked to 10 using dichlor.. but all day fc was going down and ph going up

  6. Back To Top    #6
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    Your FC is dropping in the day time because your CYA is too low ... the dichlor is adding the CYA, so make sure you do not end up using too much and raising the CYA too high.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  7. Back To Top    #7

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    i was told to get ph to the right level before shocking .. so now i need to lower ta and ph.. after the levels are ok only then should i add dichlor to bring cya up and fc?

  8. Back To Top    #8
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    You need to keep adding chlorine (whether you use dichlor or preferably liquid ... the dichlor is helping the CYA situation , but not a long term solution).

    You are correct that you need to adjust the pH first ... clearly 2 L was not nearly enough to get you in the low 7s. Keep adding acid and testing after an hour or so until it stays in the low 7s. Doing this is going to automatically lower the TA some.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  9. Back To Top    #9

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    i added 3l of 16% acid 1h ago

    since our new house isnt done yet we dont live there so i can only measure ph in the am

    after i add acid .. if i read it right you said i can measure ph levels after 1h?

  10. Back To Top    #10
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    It takes no more than an hour for most chemicals to mix through the water with the pump on.

    That acid is pretty weak. According to poolcalculator, to drop from 8.7 to 7.2 would require almost 7L (of course adding that much at once is not a good idea). I would guess you will need at least another 3L if you test again after an hour.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  11. Back To Top    #11

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    ok ill try again tomorrow.. cant source stronger than 16%
    thx for the help. appreciate it

  12. Back To Top    #12

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    Ph went down only to 8.5 even though i added 3l of 16% acid.
    Any idea whats going on?

  13. Back To Top    #13

    Re: why does ph go back up?

    Are you testing pH while FC is above 10? pH test is not reliable at FC above 10.

    Also, if you use dichlor to shock you are increasing the CYA and must calculate the new CYA after that addition to determine the new shock level for the new CYA level. It is easier to use a chlorine source that does not include CYA if you can find it.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

  14. Back To Top    #14
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: why does ph go back up?

    Quote Originally Posted by anonapersona
    Are you testing pH while FC is above 10? pH test is not reliable at FC above 10.

    Also, if you use dichlor to shock you are increasing the CYA and must calculate the new CYA after that addition to determine the new shock level for the new CYA level. It is easier to use a chlorine source that does not include CYA if you can find it.
    You must not be paying attention to his other threads. Plain CYA is apparently unknown in Serbia. Dichlor is the best choice for him.
    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.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  15. Back To Top    #15
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    most of tests here max out around 8.2 or so. And the test shows that even if it is higher, so likely your pH is just very high and the high TA makes changing it difficult.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  16. Back To Top    #16
    UnderWaterVanya's Avatar
    Join Date
    Jun 2012
    Location
    Mint Hill, NC
    Posts
    2,589

    Re: why does ph go back up?

    I'm betting the acid is weaker than spec says. Is dry acid available there?
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

  17. Back To Top    #17

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    Ph at 7.4!!! Took twice the dosage of acid leading me to believe the acid is weaker than stated as vanya suspected...

    Also picked up a dtd tablet tester and its more accurate than aqvacheck.. btw aqvacheck digital sucks it always shpws different values

  18. Back To Top    #18
    UnderWaterVanya's Avatar
    Join Date
    Jun 2012
    Location
    Mint Hill, NC
    Posts
    2,589

    Re: why does ph go back up?

    Quote Originally Posted by SerbianPoolGuy
    Ph at 7.4!!! Took twice the dosage of acid leading me to believe the acid is weaker than stated as vanya suspected...

    Also picked up a dtd tablet tester and its more accurate than aqvacheck.. btw aqvacheck digital sucks it always shpws different values
    All the digital color matching methods seem to have problems with repeatability. I'd rather have a test that gives the same result over and over when done in the same way than one that doesn't any day! LOL

    Your pool is fantastic and I'm crossing my fingers that you have a trouble free pool.
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

  19. Back To Top    #19

    Join Date
    Aug 2012
    Location
    Serbia (Europe)
    Posts
    65

    Re: why does ph go back up?

    I just read that high TA could be caused by a pool being new, (plaster pool) my pool is made of concrete, and it has mosaic tiles and in between is filled with... plaster? (not sure how u say it in english) could this cause the high TA?

    If yes, then what do i do?

  20. Back To Top    #20
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: why does ph go back up?

    how new is the tile?

    The solution is just to keep adding acid to lower the pH to start in range which will also lower the TA. See the article in Pool School about lowering TA.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •