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Thread: Should All Drops Be the Same Size?

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    Should All Drops Be the Same Size?

    Last year when I ran out of R-0009 I bought a .75 oz. size bottle at Leslie's to resupply my TFP-100 kit for that one reagent. I'm still using the 1.0 oz. R-0007 and R-0008 bottles that came with my refill set from the TFP website.

    I notice that the drops from the 1.0 oz. bottles of R-0007 and R-0008 seem much larger than the drops from the .75 oz. bottle of R-0009 from the pool store. Yes, I'm wiping the tip of the bottle and they still seem smaller. So I'm wondering if my TA is reading a little high.

    Should the drops be the same size from the different bottles? Has anyone heard of a defective bottle tip that produces smaller drops than normal?
    9,200 gal. Gunite Luna Quartz French Grey pool with spill over spa, two fountains on tanning ledge (rarely used)
    Pentair Whisperflo 2HP, Pentair CCP Cartridge 420 Sq. Ft., Polaris 280 with booster pump
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    Re: Should All Drops Be the Same Size?

    Why would you compare the drop size of different reagents?

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    Re: Should All Drops Be the Same Size?

    I'm wondering if my TA is reading higher than it is and if this is the reason. In the past I've noticed that my TA reading will go up or down by 10-20 whenever I open a new bottle of R-0009. Perhaps this is within the margin of error of the test.

    Based on your reply, do you believe the different reagent bottles have their own unique drop size? The 1 oz. reagent bottles (the bottles seem identical) for R-0007 and R-0008 seem to produce the same size of drop as far as I can tell.
    9,200 gal. Gunite Luna Quartz French Grey pool with spill over spa, two fountains on tanning ledge (rarely used)
    Pentair Whisperflo 2HP, Pentair CCP Cartridge 420 Sq. Ft., Polaris 280 with booster pump
    Pentair EasyTouch 4, RayPak LoNox 266k Natural Gas heater, Aqua Rite SWCG T Cell 9, Borates, TF-100 test kit

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    JasonLion's Avatar
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    Re: Should All Drops Be the Same Size?

    The drops of different reagents of the same brand are generally supposed to be the same size. But different brands sometimes use different drop sizes.

    The TA test tends to have static electricity issues. Sometimes you need to wipe the tip with a damp tissues at regular intervals to insure consistent drop size.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Should All Drops Be the Same Size?

    Houtex,

    Yes, the drop size matters....you are being very observant and that's a good thing!

    Here's the deal (and this ONLY applies to R-0009....none of the other reagents)......

    When you buy very fresh R-0009, it is often possible for a static charge to develop between the liquid and the dropper tip.

    When this occurs, the drop (instead of falling off the dropper tip from gravity) actually "jumps" off the tip before it is fully formed and the subsequent drops size is smaller than a normal drop.

    The end result is your TA test will read high.

    Wiping the tip with a damp cloth or paper towel in between drops always eliminates this issue so I cannot understand why that didn't correct your problem.

    The issue always goes away after just a few weeks at most so it only occurs when your R-0009 is very new and fresh.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Should All Drops Be the Same Size?

    I noticed the drop size for R-0011L (Calcium Indicator) is very small. It seems very "sticky." This is normal, yes?
    16k gal, 28'x3.5', Vinyl A/G, 1hp Pentair Dynamo 2-speed Pump, Hayward S160T Sand Filter, Intermatic HB800RCL Digital Timer, Intex 8110 SWG, TF-100 Test Kit, SpeedStir Author: Jesse's Graphical Pool Testing Log

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    Re: Should All Drops Be the Same Size?

    The drop size in the Taylor kits (including the TFTestkits based on Taylor) should be 24 drops +/- 1 per milliliter. That's 120 drops in 5 ml or 240 drops in 10 ml.
    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
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    Re: Should All Drops Be the Same Size?

    Quote Originally Posted by JesseWV View Post
    I noticed the drop size for R-0011L (Calcium Indicator) is very small. It seems very "sticky." This is normal, yes?
    Mine is the same way. That's why I originally answered that I wouldn't expect a drop from one reagent to another to be the same size.

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    Re: Should All Drops Be the Same Size?

    Fortunately, the relatively viscous R-0011L drop size is not critical. The number of drops for indicator dyes is not that important. You need enough so that the color transition is easily seen but an excess of dye is not usually a problem and for the pH test I sometimes use less than 5 drops to better match the color comparator. Where the drop size really matters most is for the titration reagents where you are counting the drops.
    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: Should All Drops Be the Same Size?

    Thanks for the replies. Very helpful.
    9,200 gal. Gunite Luna Quartz French Grey pool with spill over spa, two fountains on tanning ledge (rarely used)
    Pentair Whisperflo 2HP, Pentair CCP Cartridge 420 Sq. Ft., Polaris 280 with booster pump
    Pentair EasyTouch 4, RayPak LoNox 266k Natural Gas heater, Aqua Rite SWCG T Cell 9, Borates, TF-100 test kit

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