Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 12 of 12

Thread: how important are the "two dippers" for the chlorine test?

  1. Back To Top    #1

    Join Date
    Feb 2013
    Location
    Tucson, AZ
    Posts
    134

    how important are the "two dippers" for the chlorine test?

    I'm getting FC #'s all over the map. The directions call for "two dippers" of the R-0870 DPD powder. This seems very non-repeatable to me. Sometimes the crystals clump together, sometimes a few stick to the dipper. Also there's no compensation for 10 ml vs 25 mL sample? How important is the amount of crystals to the test results? Or can I just add any amount that turns the sample pink?
    25K gal IG plaster pool w/ spillover jacuzzi, 12 Gulf Solar coils (leaking/currently bypassed), ancient Raypak propane heater (rusted/currently bypassed), Pentair 001018 VS pump, 4.9 sq ft Triton II sand filter, Taylor K-2006 FAS-DPD kit

  2. Back To Top    #2
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: how important are the "two dippers" for the chlorine tes

    If you have one or two undissolved crystals before you start adding drops, you have enough.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  3. Back To Top    #3

    Join Date
    Jul 2012
    Location
    Dumfries & Galloway, Scotland
    Posts
    296

    Re: how important are the "two dippers" for the chlorine tes

    my experience is I use a heaped spoonful of powder, and providing I get a good solid pink colour after swirling, the result is accurate.
    Stuart Murray
    Scotland UK
    UK NPPOC

  4. Back To Top    #4
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    Location
    East Texas
    Posts
    9,002

    Re: how important are the "two dippers" for the chlorine tes

    I pretty much use one just over level spoon full and has been said, as long as I get a good pink........I'm good to go. I always have varying amounts of undissolved.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  5. Back To Top    #5
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: how important are the "two dippers" for the chlorine tes

    The amount you really need varies with the FC level. The higher the FC level, the more powder you need to use. If the sample turns pink right when you add powder, and then goes clear or brown you aren't using enough powder.

    It is always safer to use a little extra, rather than too little. Using too little will give you false low results. Using too much, within reason, won't affect the results.
    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

  6. Back To Top    #6

    Join Date
    Feb 2013
    Location
    Tucson, AZ
    Posts
    134

    Re: how important are the "two dippers" for the chlorine tes

    ok, so the degree of pinkness is not critical to the accuracy of the test? just add enough till it turns pink and stays pink
    25K gal IG plaster pool w/ spillover jacuzzi, 12 Gulf Solar coils (leaking/currently bypassed), ancient Raypak propane heater (rusted/currently bypassed), Pentair 001018 VS pump, 4.9 sq ft Triton II sand filter, Taylor K-2006 FAS-DPD kit

  7. Back To Top    #7
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: how important are the "two dippers" for the chlorine tes

    Yes. As long as the water stays pink you are good.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  8. Back To Top    #8
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: how important are the "two dippers" for the chlorine tes

    Well, yes and no. If the solution goes pink and then clear you have obviously used too little powder. But if you could somehow add just enough to get it slightly pink again that wouldn't be enough. The odds are heavily against that happening however. If you add more, chances are it is more than enough or not nearly enough. Or to put that another way, the range over which it can be slightly pink is very narrow compared to the size of even that tiny spoon. The odds of hitting that narrow range are quite low.

    The rule Stuamurr mentioned, add till you get a good solid pink is a good rule in all cases except one. If the FC level is quite low then nothing will ever turn it a good solid pink. But given your FC level is above perhaps 1 or 2, then the solid pink rule works well.
    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

  9. Back To Top    #9

    Join Date
    Feb 2013
    Location
    Tucson, AZ
    Posts
    134

    Re: how important are the "two dippers" for the chlorine tes

    here are today's test results:

    temperature: 74 avg (needed my wetsuit in the deep end!)
    pH: 7.6
    CYA: ~50
    FC: 2-4
    CC: 0
    TA: 150.36
    CH: 200

    So when I ran the free chlorine test on a 25 mL sample, I got 4 ppm. When I ran it on the same sample in 10 mL size, I got 2 ppm. Am I correct in assuming the larger sample test would be more accurate?
    25K gal IG plaster pool w/ spillover jacuzzi, 12 Gulf Solar coils (leaking/currently bypassed), ancient Raypak propane heater (rusted/currently bypassed), Pentair 001018 VS pump, 4.9 sq ft Triton II sand filter, Taylor K-2006 FAS-DPD kit

  10. Back To Top    #10
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: how important are the "two dippers" for the chlorine tes

    How many drops did you use for each FC test? That is a large difference.

    Was it really 20 drops with 25ml and only 4 drops with 10ml?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  11. Back To Top    #11

    Join Date
    Feb 2013
    Location
    Tucson, AZ
    Posts
    134

    Re: how important are the "two dippers" for the chlorine tes

    sorry, reported it backwards

    10 drops in the 25 mL sample = 2 ppm
    8 drops in the 10 mL sample = 4 ppm
    25K gal IG plaster pool w/ spillover jacuzzi, 12 Gulf Solar coils (leaking/currently bypassed), ancient Raypak propane heater (rusted/currently bypassed), Pentair 001018 VS pump, 4.9 sq ft Triton II sand filter, Taylor K-2006 FAS-DPD kit

  12. Back To Top    #12

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

    Re: how important are the "two dippers" for the chlorine tes

    At normal FC levels, the main issue with using too little powder, especially if you were to use a 25 ml sample size, is that the endpoint transition is weaker since the dye color before that last drop is less saturated in color since chlorine mostly but not completely oxidizes the dye (i.e. there is an equilibrium involved). For a 10 ml sample size, this usually isn't much of an issue and using a heaping single scoop usually works well for most people.
    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"

Posting Permissions

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