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Thread: DPD powder questions

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    DPD powder questions

    I have a Taylor K-2006 test kit which uses DPD powder for the free chlorine test. There are 2 options for volume of water sample- 10 ml and 25 ml. Two dippers of powder are specified for the test in both cases. Would 1 dipper be sufficient for the 10 ml samle? Also, sometimes a small amount of the powder will not dissolve, even when shaken vigorously. Will this affect the test results?
    Commercial,100 K, Liquid chlorine, Indoor, Heated to 86 with Jandy Lite 2 gas heater, High-Rate Sand Triton TR-100 filters (3), 7.5 HP pump motor, IG, Plaster.

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    Melt In The Sun's Avatar
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    Re: DPD powder questions

    Yes, the small side is for the smaller sample size.

    No, not having it all dissolve will not affect the test results.
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    Re: DPD powder questions

    Quote Originally Posted by Melt In The Sun
    Yes, the small side is for the smaller sample size.
    Thanks for your reply. My scoop only has one size, one measure. One end is a flat rectangle and the other is a small scoop.

    Mike
    Commercial,100 K, Liquid chlorine, Indoor, Heated to 86 with Jandy Lite 2 gas heater, High-Rate Sand Triton TR-100 filters (3), 7.5 HP pump motor, IG, Plaster.

    Jesus is my Lifeguard!

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    Melt In The Sun's Avatar
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    Re: DPD powder questions

    Oh, duh...brain fart there. The flat side is the handle. You can use the 25 mL sample size to get 0.2 ppm resolution on the test, but few people ever do since it's not really necessary.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
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    Re: DPD powder questions

    As long as the solution turns pink and remains pink (until you count the drops of R-0871), then the powder was adequate. So, yes, you can sometimes get by with one scoop.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Whatrymes's Avatar
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    Re: DPD powder questions

    Quote Originally Posted by duraleigh
    As long as the solution turns pink and remains pink (until you count the drops of R-0871), then the powder was adequate. So, yes, you can sometimes get by with one scoop.
    Doesn't the TF-50 DPD powder call for ONE heaping scoop for either 10 ml or 25 ml sample?
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    Re: DPD powder questions

    The TF-100 assumes you will do a 10ml test and suggests one heaping scoop. The kit does not contain instructions for the 25ml test.

    Regardless, the important info to take away from this is it doesn't matter exactly how much powder you use. As long as the solution turns pink and stays pink, the test is valid!
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    frogabog's Avatar
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    Re: DPD powder questions

    Less than 1 scoop (half even) has always worked for me so far. I'm baffled that it could possibly take more than one level scoop, however I have a theory that it has to do with chlorine levels.

    Our water has never been below 3ppm when using it, so I do not know if it might take two whole heaping scoops if one had less chlorine than that. The large chunks do not dissolve for me either, nor do they work to turn the water pink if the scoop only contains large chunks.
    Where kids swim in 54 degree water, turn blue, and giggle happily cuz they got a POOL!
    Year 3 BBB -15' x 48" Intex Metal Frame - Was using (2) 1000gph Intex cartridge filters (see Full time pumping Intex). 2012, converted to 1600gph and sand filter+SWG = Sand filter love affair!
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    JasonLion's Avatar
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    Re: DPD powder questions

    It does have to do with the TC level. The higher the TC level you are trying to measure the more powder you need.
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    frogabog's Avatar
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    Re: DPD powder questions

    Oh, ok. I was thinking the opposite. That more FC meant less powder needed. Good to know. Thank you Jason.
    Where kids swim in 54 degree water, turn blue, and giggle happily cuz they got a POOL!
    Year 3 BBB -15' x 48" Intex Metal Frame - Was using (2) 1000gph Intex cartridge filters (see Full time pumping Intex). 2012, converted to 1600gph and sand filter+SWG = Sand filter love affair!
    Don't waste time and energy looking for a better value on test kits, the TF100 is the best deal around. I did the looking and spent the extra money, but you don't have to make the same mistake. Just go here: TFTestkits. I use Pool Calculator for min/max, and shocking chlorine levels.

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    Re: DPD powder questions

    Thanks to all for your time and replies.
    Commercial,100 K, Liquid chlorine, Indoor, Heated to 86 with Jandy Lite 2 gas heater, High-Rate Sand Triton TR-100 filters (3), 7.5 HP pump motor, IG, Plaster.

    Jesus is my Lifeguard!

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