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Thread: Testing Bromine with TF100 FAS/DPD

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    Testing Bromine with TF100 FAS/DPD

    Question ... when I test my brominated hot tub water with the FAS/DPD test, is there some finagling I have to do with the number I get in order to "correct" for Bromine (since it's a Chlorine test)? I think I'm getting a little confused from reading things like "10ppm bromine sanitizes like 5ppm chlorine" and so on.
    So, for example, it took 20 drops to turn the pink test water to clear tonight. Does that mean I have 10ppm of total bromine? Or does it mean that I have 25ppm total bromine (since I read somewhere that you multiply the chlorine test by 2.25 to get your bromine reading)?

    Confused....
    Wes
    1) In-Ground pool with vinyl liner
    - ~25,000 gallons
    - Sand Filter
    - 1 HP pump
    - BBB method working perfectly since 2010
    2) Four Winds Honolulu Spa
    - ~450 gallons
    - 3 step bromine

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    Join Date
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    Re: Testing Bromine with TF100 FAS/DPD

    You multiply your chlorine result by 2.25 so 20 drops with a 10 ml sample size would be 10 ppm free chlorine so 22.5 ppm total bromine.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Testing Bromine with TF100 FAS/DPD

    Yowza ... so now I'm left wondering why my bromine is so high. I'm not entirely sure if my tub (purchased used, about a year old) has an ozonator or not, so maybe that's the problem. I've been leaving a floater in the tub too, so maybe that and the ozonator are causing the high reading. Reason I'm assuming that I do have an ozonator is because when I had all the side panels off the tub to add some insulation around it, I noticed a small plastic box mounted to the frame which said something about ozonator. I wasn't sure that was 'the' ozonator because it was so small though - only about the size of a wallet. That must've been it...
    Wes
    1) In-Ground pool with vinyl liner
    - ~25,000 gallons
    - Sand Filter
    - 1 HP pump
    - BBB method working perfectly since 2010
    2) Four Winds Honolulu Spa
    - ~450 gallons
    - 3 step bromine

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    Join Date
    Aug 2010
    Location
    Columbia, SC
    Posts
    96

    Re: Testing Bromine with TF100 FAS/DPD

    I this testing with the r-0871 reagent? I see there is a r-0872 reagent for bromine. Do I need both or can I correct the chlorine test and use for bromine?
    20K Gal Blue Plaster IG with rock waterfall, Beach Entry, Hayward Goldline Pro Logic controller and SWG,
    Sta-Rite System 3 S7M400 cartridge filter, 1-1/2 HP pump, Energy Therm Heat Pump, Nexxus Savi LED lighting

    500 Gal Dynasty Miramax Fiberglass Cinema Spa

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    Join Date
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    Re: Testing Bromine with TF100 FAS/DPD

    You can use the R-0871 and correct for the small difference, which really is no big deal. For a 10 ml sample size, each drop is 1.125 ppm bromine while for a 25 ml sample size each drop is 0.45 ppm bromine. If you had the R-0872 then it would be 1.25 ppm and 0.50 ppm so really not that much of a difference.

    Note that the test is measuring Total Bromine and there is no need for the R-0003 reagent. Combined Bromine is automatically measured in the first part of the test since monobromamine is in equilibrium with a more reactive monobromammonium ion that reacts with the dye in the test. It is this reactivity that makes the combined bromine still effective as a disinfectant (though monobromamine can smell if it gets high enough in concentration).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Testing Bromine with TF100 FAS/DPD

    So for the most part I can follow the same instructions. Amazing. I have been trying to find the best place to get the R-0872 for about a week now.

    For the quick test for bromine though... I have both the oto and DPD drop tests. Which tends to be better? I think I can see the differences on the oto but I though the DPD was supposed to be more accurate.
    20K Gal Blue Plaster IG with rock waterfall, Beach Entry, Hayward Goldline Pro Logic controller and SWG,
    Sta-Rite System 3 S7M400 cartridge filter, 1-1/2 HP pump, Energy Therm Heat Pump, Nexxus Savi LED lighting

    500 Gal Dynasty Miramax Fiberglass Cinema Spa

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    JasonLion's Avatar
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    Re: Testing Bromine with TF100 FAS/DPD

    OTO is best for checking for zero/non-zero sanitizer levels. The shades of yellow all tend to look the same between 3 and 8. DPD is prone to getting false zero readings when the sanitizer level is too high, but is much better at distinguishing between 3 and 5 and 8.
    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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    Re: Testing Bromine with TF100 FAS/DPD

    i am trying to get a routine for testing. but I wind up testing with the FAS-DPD test almost every time anyway. I get OCD about testing and I am sure I overtest. I have all three tests but the OTO and DPD drop tests are both just about out and I am trying to figure out what to reorder. I have a salt system for the pool and use bromine in the spa.
    20K Gal Blue Plaster IG with rock waterfall, Beach Entry, Hayward Goldline Pro Logic controller and SWG,
    Sta-Rite System 3 S7M400 cartridge filter, 1-1/2 HP pump, Energy Therm Heat Pump, Nexxus Savi LED lighting

    500 Gal Dynasty Miramax Fiberglass Cinema Spa

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