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Thread: OTO or DPD?

  1. #1
    Member jeffcessna's Avatar
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    OTO or DPD?

    I cant seem to find a definite answer and was wondering if you only have either an OTO or DPD test kit (like I do) which one would be better to use?
    Intex 20' metal Ultra Frame round 9400 gal, standard 1500 gal/hr Intex cartridge, K-2005 Test Kit, AG, vinyl -- my practice pool until we can get a real AG or IG....:)

  2. #2
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    Re: OTO or DPD?

    For the kind of testing needed to manage your pool really well, I would say neither. Most people find the FAS/DPD chlorine test an invaluable part of their testing and wouldn't use anything else.

    OTO tests for the presence of chlorine but it's accuracy is good for little else. I have never used DPD.
    Dave S.
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  3. #3
    Administrator JasonLion's Avatar
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    Re: OTO or DPD?

    It depends on what you are doing. They both have advantages and disadvantages, just in different places. DPD can distinguish between FC and CC, which OTO can't. On the other hand DPD will show zero chlorine when the FC level is actually very high. DPD is noticeably better at distinguishing between FC levels around 3 to 5.

    The FAS-DPD test is much better than either of those in nearly every way.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  4. #4
    Senior Member Isaac-1's Avatar
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    Re: OTO or DPD?

    I find the OTO test kit included in the TF100 kit to be handy for quick ball park chlorine level checks, but it is a BIG ballpark and it is also handy as a double check against the FAS-DPD, I have used tests that were DPD in the past, they are somewhere in the middle, a little easier than doing the FAS-DPD, but have the color matching problems of OTO.

    So

    OTO - quick easy 1 step ballpark total chlorine number

    DPD - mid level test but tells you both FC and CC (at least in a ballpark)

    FAS-DPD little more work than DPD, but tells you to the .5 PPM level for both FC and CC and best of all NO COLOR MATCHING just pink or clear
    Indoor 20x40 36,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis panel roof top solar heat with Aquasolar controller, Dolphin Diagnostic Pro Robot Cleaner. Also LMI metering chlorine dispenser pump and soon to be connected UV Ozonator and now Hot Spring Jetsetter standalone spa
    I use and endorse the TFtestKits TF-100 from http://tftestkits.net

  5. #5
    Senior Member poolgirl22's Avatar
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    Re: OTO or DPD?

    ditto what isaac said.

    since my target on the high end is 9 and my minimum is 4 or 5, there's a biiiiigggg range there on the OTO.

    I use FAS DPD every day. Sometimes twice.
    Backyard pool-less, but used to be.....
    16,100 gallon, 18x38 3.5 ft deep oval AG, Vinyl, Sand, 1hp pump
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  6. #6
    Member jeffcessna's Avatar
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    Re: OTO or DPD?

    I went to my local pool store (Pool and Spa Depot) and asked to see if they maybe carried the FAS-DPD test and they didn't have any idea what I was talking about. I tried to explain to them what it was and the man behind the counter told me, "We don't get that technical." I was taken aback and decided that there was no way I was going back in that store again....ugh. I am going to have to eventually just get the FAS-DPD test kit so I can test accordingly. For the time being I will continue to use the OTO for daily tests and the DPD maybe every other day to TRY to verify.
    Intex 20' metal Ultra Frame round 9400 gal, standard 1500 gal/hr Intex cartridge, K-2005 Test Kit, AG, vinyl -- my practice pool until we can get a real AG or IG....:)

  7. #7
    Senior Member poolgirl22's Avatar
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    Re: OTO or DPD?

    Jeff,
    Eventually is NOW. Just order that test alone and it will change everything.
    Backyard pool-less, but used to be.....
    16,100 gallon, 18x38 3.5 ft deep oval AG, Vinyl, Sand, 1hp pump
    http://www.poolservicestech.com Liquidator
    http://www.poolcalculator.com/
    http://www.tftestkits.net TFT100 test kit

  8. #8
    Member jeffcessna's Avatar
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    Re: OTO or DPD?

    I was just looking at the Taylor website and I can just order the R-0870 powder and the R-0871 drops for the FAS-DPD test kit instead of ordering the entire kit.
    Intex 20' metal Ultra Frame round 9400 gal, standard 1500 gal/hr Intex cartridge, K-2005 Test Kit, AG, vinyl -- my practice pool until we can get a real AG or IG....:)

  9. #9
    Senior Member Isaac-1's Avatar
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    Re: OTO or DPD?

    You would also need R-003 for the combined chlorine part of the test, a graduated cylinder to get the correct amount of water and the little scoop for the powder. To me is seems easier to order the K-1515 kit as you get a box to keep it in, etc. Note if you use non-chlorine shock like HTH Shock n Swim you want to get K-1518
    Indoor 20x40 36,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis panel roof top solar heat with Aquasolar controller, Dolphin Diagnostic Pro Robot Cleaner. Also LMI metering chlorine dispenser pump and soon to be connected UV Ozonator and now Hot Spring Jetsetter standalone spa
    I use and endorse the TFtestKits TF-100 from http://tftestkits.net

  10. #10
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    Re: OTO or DPD?

    You can either get the Taylor K-1515 FAS-DPD chlorine test kit here or you can get the FAS-DPD chlorine test kit from TFTestkits here with the latter kit having 2.67 times the volume of reagents so is less expensive per test.
    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"

  11. #11
    Member jeffcessna's Avatar
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    Re: OTO or DPD?

    I don't use shock at all. Just the BBB method Is there any preference as to which test kit to get for just the FAS-DPD test??
    Intex 20' metal Ultra Frame round 9400 gal, standard 1500 gal/hr Intex cartridge, K-2005 Test Kit, AG, vinyl -- my practice pool until we can get a real AG or IG....:)

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