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Thread: Iron Stains Back After AA Treatment

  1. Back To Top    #1

    Join Date
    Jun 2010
    New Hampshire

    Iron Stains Back After AA Treatment

    I did the AA treatment and it worked great. It took a week for the pool to start holding FC, but it finally did.

    Then we put 6 cal-hypo pucks in the skimmer and a couple things happened:
    1] pool got cloudy
    2] stains came back

    The cloudiness cleared overnight, and is common (as I understand) with cal-hypo in high quantities. I am learning from this site, and use liquid chlorine and cal-hypo pucks for chlorine sources. I may abandon the cal-hypo pucks (I switched to them away from the Trichlor pucks because of our high CYA levels - we have low hardness and a vinyl liner).;

    As for the stains coming back, I found this from the bottom of the AA instructions on this site:

    "High ph along with high chlorine will precipitate any metals that are not sequestered out of the water and on to the surface of the pool again. If this happens take the ph back down to 7, or 7.2 and add more sequestering agent. This should lift the stain off."

    It would seem our 6 cal-hypo pucks represented an accidental "shocking" so the FC shot up...and the pH shot up from the cal-hypo...does that make sense? I read that cal-hypo has high pH.

    I brought the pH down to 7 and added lots of sequestering agent. This didn't work, so I think I'll do AA again....but in the future, per the passage above, it would seem that "high FC + high pH = Stains Return."

    Does liquid shock increase pH? Would it be worth adding muriatic acid while (or just before) shocking to help prevent a pH increase.

    To recap:
    1] is this the key for me? "high FC + high pH = Stains Return"
    2] what's the best way to shock my pool and keep pH low?

    30,000 gallons / sand / IG / Vinyl

  2. Back To Top    #2

    Re: Iron Stains Back After AA Treatment

    i did the aa treatment last week also. stains all disappeared and everything looked
    great after 2 days. on day 3 some stains came back. at that time , i checked ph
    and found it had risen to 7.6. added muratic acid to lower ph back down to 7.0,
    and the next day all stains were gone again. now 5 days later it looks great. i
    just monitor the ph and keep it from 7.0 to 7.2.
    24,000 gallon ig fiberglass pool
    1 hp hayward pump
    hayward sand filter (250 lb)
    madisonville, ky

  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Iron Stains Back After AA Treatment

    The stains will only come back if you are using too little sequestrant. So it is really, too little sequestrant and also either high PH and/or too much chlorine means the stains will come back.
    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

  4. Back To Top    #4
    buddywiser's Avatar
    Join Date
    May 2007
    Morgantown, WV

    Re: Iron Stains Back After AA Treatment

    What kind of sequesterant are you using? I've had some staining problems also, but seem to have them under control now using Pool Magnet Plus.

    Jason and Chemgeek break down the good ones here:

    24000 Gal, 18x36 Vinyl
    Hayward Super Pump
    Jacuzzi Tri Clops Cartridge Filter
    Heat Siphon Heat Pump

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