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Thread: DPD Test. No Pink

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    DPD Test. No Pink

    Using the DPD test (r870 powder) the solution turns pink for just a second and then goes back clear. In other words showing no chlorine. HOwever i know there is a bunch in there. Using the yellow test vial that is with the pH test, it shows off the charts.

    What is up?
    10,000 gallon
    Viking Freeform Fiberglass Inground Pool. FNS Plus DE Filter Pentair Challenger .75hp pump


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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: DPD Test. No Pink

    R-0870 powder is used in the FAS-DPD chlorine test. The DPD chlorine test is very different.

    If when you add the R-0870 the sample remains clear, your chlorine level is probably zero. However, if it goes pink for a moment and then back to clear (or brown) you haven't used enough R-0870 powder. Because of that "for a moment" thing it is good to double check with the OTO test, which is extremely reliable for chlorine vs no chlorine testing. If the sample remains clear with the OTO test, there really isn't any chlorine. Really high FC levels are the most likely to go pink for a moment and then back to clear. If OTO shows chlorine, just add more R-0870 powder.
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