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Thread: DPD tests

  1. Back To Top    #1

    Join Date
    May 2010
    Location
    Fairfax Station, VA
    Posts
    52

    DPD tests

    I am new to this forum and have been reading many of the posts.
    I have tested chlorine levels with DPD drops (Taylor) and DPD tablets (No. 1 and 3) that I have - I don't have an FAS test kit yet. The drops are fresh bottles.
    With the DPD drops, I get a much lower reading than the tablets. The tabs can have a FC 3 and the drops 1. No CC. I brought a sample over to local pool store that uses the Waterlink Express and their value was closer to the DPD tablet reading. Anyone know why there is a discrepancy between the tests?
    35K gallon plaster IGP, free form, spa with spill-over; Sta-Rite 2HP pump; KDI American 48sq.ft., 144GPM DE filter; Pentair MiniMax heater; pressure side The PoolCleaner; Circupool RJ45

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    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
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    37,887

    Re: DPD tests

    It is possible that your DPD drops have gone bad. If everything was working correctly they should agree with each other more closely than that.
    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

    Join Date
    May 2010
    Location
    Fairfax Station, VA
    Posts
    52

    Re: DPD tests

    That was my first thought. Brand new bottles from the pool store. I don't know how long they have been there, but I assume they are from a new lot this season. Maybe I can contact Taylor with the lot no. I tend to trust the tablets more.
    Thanx.
    35K gallon plaster IGP, free form, spa with spill-over; Sta-Rite 2HP pump; KDI American 48sq.ft., 144GPM DE filter; Pentair MiniMax heater; pressure side The PoolCleaner; Circupool RJ45

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