Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 4 of 4

Thread: Shocked last night....FC fine....big PH increase

  1. Back To Top    #1

    Join Date
    Sep 2007
    Location
    Gloucester County, NJ
    Posts
    141

    Shocked last night....FC fine....big PH increase

    Before shocking the pool with 12.5% liquid chlorine, I had the following numbers:

    FC .5
    CC 1
    PH 7.2
    TA 70
    CH 210
    CYA 40

    I put in enough chlorine to take the FC level to 15, based on Jason's Poolcalculator. This morning, my levels are:

    FC 15
    CC 0
    PH 8 <<-- This is where my question lies
    TA 70
    CH 210
    CYA 40

    So, as you see, the FC level appears to have held overnight, which I wasn't expecting. However, my PH level shot through the roof. I had put in muriatic acid to bring down the PH as the PH was really high when I opened the pool. I expected it to drift upward, but between yesterday evening and this morning it increased dramatically. I don't want to just add more acid as I know that will also reduce my TA. I also don't want to just add baking soda to raise the TA as that will also raise the PH. What's the best approach here?
    28,000 gallon gunite/white plaster with 30ft RBB and 2ft sheer descent, 100 sq ft thermaledge, 50sq ft spa w/ 6 jets
    2HP Jandy pump, 60sq ft Jandy DE filter, 400,000 BTU Jandy LX Nat Gas Heater, 2 Jandy color lights + Jandy color spa light, Jandy Aqualink RS6, Jandy AquaPure 1400

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879
    Don't worry about the PH while the FC level is very high. Wait till FC is back down to 10 or below and then test the PH again. High FC levels will cause the PH to read higher than it really is.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,090
    Don't trust your pH reading when the chlorine is high.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  4. Back To Top    #4

    Join Date
    Sep 2007
    Location
    Gloucester County, NJ
    Posts
    141
    thanks guys....i'll let the FC come down to normal range and check again in a day or two.
    28,000 gallon gunite/white plaster with 30ft RBB and 2ft sheer descent, 100 sq ft thermaledge, 50sq ft spa w/ 6 jets
    2HP Jandy pump, 60sq ft Jandy DE filter, 400,000 BTU Jandy LX Nat Gas Heater, 2 Jandy color lights + Jandy color spa light, Jandy Aqualink RS6, Jandy AquaPure 1400

Posting Permissions

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