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Thread: pH Test - 5 drops or 4?

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    phalcon51's Avatar
    Join Date
    Oct 2010
    So. California

    pH Test - 5 drops or 4?

    Recently the color of my pH samples has gotten more intense and it makes it difficult to accurately determine what the proper color match is on my Taylor test kit. Nothing has changed in the chemicals I'm using however the water temp has gone from 74 deg. to 64 deg. in the last 12 days. I've found that if I only use four drops of solution I get a much more accurate color reading than if I use 5 drops. Is this still accurate? Can water temperature affect the color this way?

    Below are a couple of pictures demonstrating the difference.



    5 drops

    4 drops
    26,200 gal. 35' x 16' Plaster IGP (50 yrs. old), Hayward 48 sq. ft. DE filter, Hayward EcoStar VS pump, Intellichlor IC-40 SWCG, The Pool Cleaner 4X suction, Pool Skim and Pool Devil skimmers. Re-plastered Sept. 2010.

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    Re: pH Test - 5 drops or 4?

    The color with 5 drops looks fine. I would say right at about a pH of 7.4 to 7.5. You should use 5 drops. You could get a new bottle of the pH reagent to compare drop size and sample color.

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    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: pH Test - 5 drops or 4?

    I have a similar issue with my test kit and I use 3-4 drops instead of 5 and it works fine. It may be that my comparator has faded or that the indicator dye is more concentrated (more likely the former).
    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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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: pH Test - 5 drops or 4?

    The color is the same, regardless of how many drops you use. What varies with the number of drops is the saturation of the color. For some people, using four drops works better, for other people using six drops works better. Whatever works for you is good, the reading should be the same regardless, only the ease of matching the color really varies.
    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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