Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 8 of 8

Thread: Is it ok to add more than drop at a time to the FAS-DPD test

  1. Back To Top    #1

    Join Date
    Jun 2009
    Location
    Derry, ME
    Posts
    19

    Is it ok to add more than drop at a time to the FAS-DPD test

    Since I have a high CYA value (currently 70 but trying to get it down) I have to maintain around 10ppm of FC.
    This equals 20 drops of the FAS-DPD reagent. I don't have the fancy swirling machine so instead of swirling between each drop, I put 5 in, swirl, 5 more, swirl, than start swirling every 2 drops unil I see it start to see the test sample start to clear up. Is this affecting the accuracy of the test by doing it this way (instead of swirling after every drop)?
    15x30 Esther Williams semi-inground
    Hayward DE filter with 1/2 HP super pump
    4 2x20 Sungrabber solar panels
    TF100

  2. Back To Top    #2

    Join Date
    Mar 2011
    Location
    Sunny Central Florida
    Posts
    91

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    I do the same thing For TA & Ch too....

    I actually have perfected a swirl with my right hand while working the dropper with my left. I'm pretty proud of myself, LOL.
    IG Plaster 20,000gal, attached spa w/ spillover, hayward C12002 cart filter, 1 1/2hp pump w/ polaris 360
    6/16/12 - PH 7.6, FC 6, CC 0, CYA 30, TA 80, Calcium 310

  3. Back To Top    #3

    Join Date
    Jun 2009
    Location
    Derry, ME
    Posts
    19

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    I've tried that and I end up messing up the test!
    15x30 Esther Williams semi-inground
    Hayward DE filter with 1/2 HP super pump
    4 2x20 Sungrabber solar panels
    TF100

  4. Back To Top    #4

    Join Date
    Sep 2009
    Location
    Greentown, IN
    Posts
    914

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    I tend to do several drops at a time... just keep a close eye on it getting ready to turn so you don't overshoot your mark.
    Indiana, ABG 24'x52" Galveston by Blue Cascade (Craigslist buy w/part of deck included), 13,500 gallons, Intex SWG, solar panels mix 2, TF-100 test kit.

    Test kits compared
    Purchase test kits

  5. Back To Top    #5

    Join Date
    Jun 2009
    Location
    Derry, ME
    Posts
    19

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    Thanks a lot. I do keep an eye on it during the process.
    15x30 Esther Williams semi-inground
    Hayward DE filter with 1/2 HP super pump
    4 2x20 Sungrabber solar panels
    TF100

  6. Back To Top    #6
    techguy's Avatar
    Join Date
    Jul 2010
    Location
    Antelope, CA
    Posts
    2,687

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    I know I tend to do drops in sets of three until I get close to what I am expecting... then I drop to single drops.
    -- Guy --
    10K gallons in 21' Round 52 inch wall Aqualeader AG, Hayward Power Flow LX 1.5 HP pump motor, Hayward Perflex EC50AC DE filter w/Cellulose, Wide mouth skimmer, 2013 new Diver Dan (craigslist) to replace the faded old Hayward AquaBug. TF-100

  7. Back To Top    #7

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    Just make sure that the drops are well-formed when you add them. If you squeeze too hard and have the drops come out too quickly, then they will be smaller drops and that will affect the result making it artificially too high. Also be careful about static electricity which can make the drops "squirt" out. Y'all know what a good-looking drop looks like when you see one...
    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"

  8. Back To Top    #8

    Join Date
    Jun 2012
    Location
    Louisville, KY
    Posts
    266

    Re: Is it ok to add more than drop at a time to the FAS-DPD

    Agree on well formed drops. I know where my fc is around so I add 6 full drops and then go from there for my target of 5. Just make sure you swirl really well for a few seconds after the big dose of titrant.

    You're doing a titration. Keeping the solution thoroughly mixed is the key. Takes me maybe 5 seconds to get it all mixed up on this test. It's the easiest one.
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •