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Thread: Yellow-brown stained pool after adding alkalinity

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    Yellow-brown stained pool after adding alkalinity

    Hi,

    This forum seems active so I hope someone will have the magic answer to my problem.

    I have a 10 000L fibreglass pool. Since this Spring's openning, I had the same problem occur 3 times: the bottom of the pool turned yellowish and trying to rub it out would not work. Here is what happened.

    • openned the pool with chock treatment. Water cleared but walls and bottom were yellowish-brown.[/*:m:3qsmhsxr]
    • was told to add muriatic acid. I added a full gallon (I was mislead into putting it all) after waiting that chlorine went down [/*:m:3qsmhsxr]
    • Pool turned crystal clean and water was very inviting. But PH was of course amazingly low.[/*:m:3qsmhsxr]
    • I was given indication to add PH, alkalinity, and calcium harness. I followed instructions well.[/*:m:3qsmhsxr]
    • 2 days after, the yellow-brownish stain was back all over the pool, but more on the bottom.[/*:m:3qsmhsxr]
    • Tests did not indicate any metal in the water.[/*:m:3qsmhsxr]
    • I did another treatment with acid muriatic and stains disappeared right away.[/*:m:3qsmhsxr]
    • I emptied the pool and left around 15% of old water (can't remove all in these type of pools)[/*:m:3qsmhsxr]
    • Filled with brand new Montreal water.[/*:m:3qsmhsxr]
    • Retested with home drops and had to add some PH+.[/*:m:3qsmhsxr]
    • Resumed using chlorine "pucks" with stabilizer with very small opening in distributor (it takes a week to dissolve and chlorine tests show perfect balance).[/*:m:3qsmhsxr]
    • enjoyed pool for 2-3 weeks[/*:m:3qsmhsxr]
    • Went to perform a test at store. It indicated:
      [list:3qsmhsxr]
    • Temperature: 27.8C
      [/*:m:3qsmhsxr]
    • pH: 7.4
      [/*:m:3qsmhsxr]
    • AT: 70 mg/l
      [/*:m:3qsmhsxr]
    • DC: 140 mg/l
      [/*:m:3qsmhsxr]
    • CYA: 25 mg/l
      [/*:m:3qsmhsxr]
    • C.L.: 2.00 mg/l
      [/*:m:3qsmhsxr]
    • C.T: 2.00 mg/l[/*:m:3qsmhsxr]
    [/*:m:3qsmhsxr][/list:u:3qsmhsxr]

    The rep suggested to add Alkalinity: 1kg. My spouse started 2 days ago with a third of that, just in case...

    Today, the **** yellowish-brown stain is back, but lighter.

    It seems to me that my pool does not like alkalinity. Any suggestion ?

    --
    Mel T.
    Montreal

  2. Back To Top    #2
    reebok's Avatar
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    Re: Yellow-brown stained pool after adding alkalinity

    sounds almost exactly like mustard algae except the rubbing and acid part. if you brushed it, nothing happened?
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  3. Back To Top    #3
    frustratedpoolmom's Avatar
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    May 2007
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    SWSuburban Chicago, IL
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    Re: Yellow-brown stained pool after adding alkalinity

    You have classic metal staining... I think...

    There are some terminology issues - we need a translator

    we go by these abbreviations

    FC - Free chlorine
    TC - Total chlorine
    CC - Combined Chloramines
    PH - I'm not sure, something complicated LOL
    TA - Total Alkalinity
    CH - Calcium Hardness
    CYA - Cyanuric Acid - stabilizer

    The water doesn't test positive for metals because they are likely imbedded in the pool surface:
    http://www.troublefreepool.com/pool-...metal%20stains

    Please note your recommended levels for a fiberglass pool:
    http://www.troublefreepool.com/pool-...mmended_levels

    Then confirm metal staining by placing a vitamin c tablet on the staining, and report the result.
    If the stain fades under the tablet, follow this process:
    http://www.troublefreepool.com/ascor...ins-t2298.html

    Hope this helps.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  4. Back To Top    #4
    Guest

    Re: Yellow-brown stained pool after adding alkalinity

    Sure sounds like iron staining to me. It's one of the big drawbacks to fiberglass pools but it is easily taken care of! It's the pH spike caused by the addition of the baking soda that makes the stains reappear after you dissolve them by dropping the pH. NOT the way to handle the problem. Raad about the ascorbic acid treatment in the post from frustratedpoolmom above THEN try the vitamin c test to make sure it's iron (even though I know it is)!

    Your alkalinity is OK at 70 for now (but if you are going to continue using trichlor you might want to bring it up to about 100) but your calcium hardness is too low and it's one of the reasons you are getting stains.
    Anyway, that can all be sorted out a bit later once you have the stains under control.
    I would strongly suggest you click on the pool school link in the upper right corner of every page.
    Read EVERYTHING in it.
    Read it all a second time.
    If you don't understand something read it a third time.
    Post any question in the forum about things you don't understand.
    This will take a lot less time than you think since all the pool school articles are very short. This will give you a good basic understanding of proper pool care the way we do it here at TroubleFreePool.
    Remember, we are not trying to sell you a lot of pool chemicals so our advice is going to be different from the pool store that is trying to sell you everything in the store.
    You do need a good test kit. since you are in Canada your choices are somewhat limited since Taylor only has one distributor in Canada and they have an exclusive. The kit you want is a Taylor K-2006. You can read about test kits in Pool School. I would suggest Apollo pools in Montreal.
    http://piscines-apollo.com/
    They are a Taylor dealer and seem to have the best prices and excellent customer service!
    They have the K-2006 for $143.50 Canadian! Paul is one of our members and a great guy!
    http://piscines-apollo.com/english_taylor.htm

    Seriously consider getting one of their magnetic stirrers also!
    http://piscines-apollo.com/english_stirrer.htm

    Read my review of it here
    portable-magnetic-stirrer-from-apollo-pools-t1489.html

    We can help you with your staining problem and hold your hand along the way. That's why we are here!

    Read pool school, try the vitamin c tablet on the stain and report back, get a good test kit like we suggest and then we can tackle those stains and help you get your water adjusted so they don't come back!

  5. Back To Top    #5
    frustratedpoolmom's Avatar
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    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,963

    Re: Yellow-brown stained pool after adding alkalinity

    Okay which one is ta and which one is CH and when did you learn to speak Canadian?
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  6. Back To Top    #6
    Guest

    Re: Yellow-brown stained pool after adding alkalinity

    Quote Originally Posted by frustratedpoolmom
    Okay which one is ta and which one is CH and when did you learn to speak Canadian?
    I had a boss from Quebec many years ago. She was a wonderful lady! I learned a bit of French but forgot it since I never really had any chance to practice it living in Florida after she sold the business and went back to Canada to take care of her mother.

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