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Thread: Iron stain removal results

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    stev32k's Avatar
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    Mar 2009
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    Iron stain removal results

    It took 15 days to get free chlorine from 4.5 ppm to zero. So finally this morning I lowered the pH to 7.2 and added 3 lb of Ascorbic Acid. The results are pretty amazing. In 1 hour the liner went from a dingy yellowish blue to a bright clear blue. Even the wheels on polaris and the PVC fitting around the skimmer were stained a dirty yellow and now look bright white and brand new.

    I bought a HACH iron test kit and so far have not been able to detect any iron in the water before or after adding the AA. I boiled 250 grams of water down to 10 grams after adding the AA and still no iron showed up in the test. The test is supposed to detect iron down to 1 ppm. I can only assume the test is faulty or the iron is in the form of ferrous and the test will only detect ferric. Has anybody used the HACH kit for iron?

    I've decided to take a chance and drain and refill the pool. It has been drained three times for liner replacements and there were no problems with the walls moving or caving in so I'm hoping I can get away with it again. If not the liner is about 8 or 9 years old and could stand replacing. So it would not hurt my feelings it I do have to do some repair.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Stenner 45 MPH10 chlorine feed pump. 1 micron final filter bags (home made and very effective)

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    JasonLion's Avatar
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    Re: Iron stain removal results

    Even ignoring ground water issues, draining a liner pool below roughly 1 foot deep in the shallow end is not recommended, especially with a liner that is more than a few years old. It is unlikely that an older liner will survive the pool being refilled.
    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

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    stev32k's Avatar
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    Re: Iron stain removal results

    Quote Originally Posted by JasonLion
    Even ignoring ground water issues, draining a liner pool below roughly 1 foot deep in the shallow end is not recommended, especially with a liner that is more than a few years old. It is unlikely that an older liner will survive the pool being refilled.
    Now you are making me worried. What do you think about the negative iron test? With as much staining as I had I expected to be able to detect iron after the AA was added.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Stenner 45 MPH10 chlorine feed pump. 1 micron final filter bags (home made and very effective)

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    JasonLion's Avatar
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    May 2007
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    Re: Iron stain removal results

    Failing to detect iron, even when iron is obviously present, happens all the time. Unfortunately, I have no idea why.
    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

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